bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s that are
adapted
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking
convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period
Period may refer to:
Common uses
* Era, a length or span of time
* Full stop (or period), a punctuation mark
Arts, entertainment, and media
* Period (music), a concept in musical composition
* Periodic sentence (or rhetorical period), a concept ...
, and modern seabird families emerged in the
Paleogene
The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
.
In general, seabirds live longer,
breed
A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slig ...
later and have fewer young than other birds do, but they invest a great deal of time in their young. Most
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
nest in
colonies
In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...
, which can vary in size from a few dozen birds to millions. Many species are famous for undertaking long annual migrations, crossing the
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
or circumnavigating the Earth in some cases. They feed both at the ocean's surface and below it, and even feed on each other. Seabirds can be highly
pelagic
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...
, coastal, or in some cases spend a part of the year away from the sea entirely.
Seabirds and humans have a long history together: they have provided food to
hunters
Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/ hide, bone/tusks, horn/antler, et ...
, guided
fishermen
A fisher or fisherman is someone who captures fish and other animals from a body of water, or gathers shellfish.
Worldwide, there are about 38 million commercial and subsistence fishers and fish farmers. Fishers may be professional or recreat ...
to fishing stocks and led
sailor
A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship.
The profession of the s ...
s to land. Many species are currently
threatened
Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensat ...
by human activities, such as from
oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s, getting trapped in nets, and by
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
and severe weather.
Conservation
Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws.
Conservation may also refer to:
Environment and natural resources
* Nature conservation, the protection and managem ...
efforts include the establishment of wildlife refugees and adjustments to fishing techniques.
Classification
There exists no single definition of which groups, families and species are seabirds, and most definitions are in some way arbitrary. Elizabeth Shreiber and Joanne Burger, two seabird scientists, said, "The one common characteristic that all seabirds share is that they feed in
saltwater
Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish water, ...
; but, as seems to be true with any statement in biology, some do not."Schreiber, Elizabeth A. and Burger, Joanne (2001) ''Biology of Marine Birds''. Boca Raton: CRC Press, However, by convention all of the Sphenisciformes (penguins) and
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, the petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still called tubenoses in English, procellariiforms are of ...
(
albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Pacifi ...
es and
petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes.
Description
The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross f ...
s), all of the
Suliformes
The order Suliformes (, dubbed "Phalacrocoraciformes" by ''Christidis & Boles 2008'') is an order recognised by the International Ornithological Congress, International Ornithologist's Union. In regard to the recent evidence that the traditional ...
(
gannet
Gannets are seabirds comprising the genus ''Morus'' in the family Sulidae, closely related to boobies.
Gannets are large white birds with yellowish heads; black-tipped wings; and long bills. Northern gannets are the largest seabirds in the ...
s and
cormorant
Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...
s) except the
darter
The darters, anhingas, or snakebirds are mainly tropical waterbirds in the family Anhingidae, which contains a single genus, ''Anhinga''. There are four living species, three of which are very common and widespread while the fourth is rarer and ...
s, and some of the
Charadriiformes
Charadriiformes (, from ''Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water an ...
(the
skua
The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called jae ...
s,
gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
s,
tern
Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...
s,
auk
An auk or alcid is a bird of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The word "auk" is derived from Icelandic ''álka'', from Old Norse ''alka'' (a ...
phalarope
__NOTOC__
A phalarope is any of three living species of slender-necked shorebirds in the genus ''Phalaropus'' of the bird family Scolopacidae.
Phalaropes are close relatives of the shanks and tattlers, the ''Actitis'' and Terek sandpipers, a ...
s are usually included as well, since although they are
wader
245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots
Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
s ("shorebirds" in North America), two of the three species (
Red
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondar ...
and Red-necked) are oceanic for nine months of the year, crossing the equator to feed pelagically.
Loon
Loons (North American English) or divers (British / Irish English) are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family Gaviidae and order Gavi ...
s and
grebe
Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably ...
s, which nest on lakes but winter at sea, are usually categorized as water birds, not seabirds. Although there are a number of
sea ducks
The sea ducks (''Mergini'') are a tribe of the duck subfamily of birds, the Anatinae. The taxonomy of this group is incomplete. Some authorities separate the group as a subfamily, while others remove some genera. Most species within the group sp ...
in the family
Anatidae
The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating ...
that are truly marine in the winter, by convention they are usually excluded from the seabird grouping. Many waders (or shorebirds) and
heron
The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychus ...
s are also highly marine, living on the sea's edge (coast), but are also not treated as seabirds.
Sea eagle
A sea eagle or fish eagle (also called erne or ern, mostly in reference to the white-tailed eagle) is any of the birds of prey in the genus ''Haliaeetus'' in the bird of prey family Accipitridae.
Taxonomy and evolution
The genus ''Haliaeetus'' ...
s and other fish-eating birds of prey are also typically excluded, however tied to marine environments they may be.
German paleontologist
Gerald Mayr
Gerald Mayr is a German palaeontologist who is Curator of Ornithology at the Senckenberg Research Institute in Frankfurt am Main, Hesse. He has published extensively on fossil birds, especially the Paleogene avifauna of Europe. He is an expert on ...
defined the "core waterbird" clade Aequornithes in 2010. This lineage gives rise to the
Gaviiformes
Gaviiformes is an order of aquatic birds containing the loons or divers and their closest extinct relatives. Modern gaviiformes are found in many parts of North America and northern Eurasia (Europe, Asia and debatably Africa), though prehistoric ...
,
Sphenisciformes
Penguins ( order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapt ...
, Procellariiformes,
Ciconiiformes
Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family called Ciconiidae, and make up the order Ciconiiformes . Ciconiiformes previously included a number of other families, such as herons a ...
, Suliformes and
Pelecaniformes
The Pelecaniformes are an order of medium-sized and large waterbirds found worldwide. As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such ...
. The tropicbirds are part of a lineage—
Eurypygimorphae
Eurypygimorphae or Phaethontimorphae is a clade of birds that contains the orders Phaethontiformes (tropicbirds) and Eurypygiformes (kagu and sunbittern) recovered by genome analysis. The relationship was first identified in 2013 based on their n ...
—that is a
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
to the Aequornithes.
Evolution and fossil record
Seabirds, by virtue of living in a
geologically
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...
depositional environment (that is, in the sea where
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
s are readily laid down), are well represented in the
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
record. They are first known to occur in the
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period, the earliest being the Hesperornithiformes, like ''Hesperornis regalis'', a flightless loon-like seabird that could dive in a fashion similar to grebes and loons (using its feet to move underwater) but had a beak filled with sharp teeth. Flying Cretaceous seabirds do not exceed wingspans of two meters; any sizes were taken by piscivorous
pterosaurs
Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...
.
While ''Hesperornis'' is not thought to have left descendants, the earliest
modern
Modern may refer to:
History
* Modern history
** Early Modern period
** Late Modern period
*** 18th century
*** 19th century
*** 20th century
** Contemporary history
* Moderns, a faction of Freemasonry that existed in the 18th century
Phil ...
seabirds also occurred in the Cretaceous, with a species called '' Tytthostonyx glauconiticus'', which has features suggestive of Procellariiformes and Fregatidae.Olson, S.; Parris, D.C. (1987). The Cretaceous Birds of New Jersey. ''Smithsonian Contributions to Paleontology'', 63: 22pp. As a clade, the Aequornithes either became seabirds in a single transition in the Cretaceous or some lineages such as pelicans and frigatebirds adapted to sea living independently from freshwater-dwelling ancestors. In the
Paleogene
The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
both pterosaurs and marine reptiles became extinct, allowing seabirds to expand ecologically. These post-extinction seas were dominated by early
Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes (or tubenoses), which also ...
, giant
penguin
Penguins (order (biology), order List of Sphenisciformes by population, Sphenisciformes , family (biology), family Spheniscidae ) are a group of Water bird, aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: on ...
s and two
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
families
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...
, the
Pelagornithidae
The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating ...
and the Plotopteridae (a group of large seabirds that looked like the penguins). Modern genera began their wide radiation in the
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
, although the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''
Puffinus
''Puffinus'' is a genus of seabirds in the order Procellariiformes that contains about 20 small to medium-sized shearwaters. Two other shearwater genera are named: '' Calonectris'', which comprises three or four large shearwaters, and '' Ardenna' ...
'' (which includes today's
Manx shearwater
The Manx shearwater (''Puffinus puffinus'') is a medium-sized shearwater in the seabird family Procellariidae. The scientific name of this species records a name shift: Manx shearwaters were called Manks puffins in the 17th century. Puffin is an ...
and
sooty shearwater
The sooty shearwater (''Ardenna grisea'') is a medium-large shearwater in the seabird family Procellariidae. In New Zealand, it is also known by its Māori name , and as muttonbird, like its relatives the wedge-tailed shearwater (''A. pacificus' ...
) might date back to the
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
. Within the Charadriiformes, the gulls and allies ( Lari) became seabirds in the late Eocene, and then waders in the middle Miocene (
Langhian
The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007)
The Langhian was a ...
). The highest diversity of seabirds apparently existed during the Late Miocene and the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58food web
A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is consumer-resource system. Ecologists can broadly lump all life forms into one ...
had undergone a period of upheaval due to extinction of considerable numbers of marine species; subsequently, the spread of marine mammals seems to have prevented seabirds from reaching their erstwhile diversity.
Characteristics
Adaptations to life at sea
Seabirds have made numerous adaptations to living on and feeding in the sea.
Wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
morphology has been shaped by the
niche
Niche may refer to:
Science
*Developmental niche, a concept for understanding the cultural context of child development
*Ecological niche, a term describing the relational position of an organism's species
*Niche differentiation, in ecology, the ...
an individual species or family has
evolved
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
, so that looking at a wing's shape and loading can tell a scientist about its life feeding behaviour. Longer wings and low wing loading are typical of more
pelagic
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...
species, while diving species have shorter wings.Gaston, Anthony J. (2004). ''Seabirds: A Natural History'' New Haven:Yale University Press, Species such as the
wandering albatross
The wandering albatross, snowy albatross, white-winged albatross or goonie (''Diomedea exulans'') is a large seabird from the family Diomedeidae, which has a circumpolar range in the Southern Ocean. It was the last species of albatross to be desc ...
, which forage over huge areas of sea, have a reduced capacity for powered flight and are dependent on a type of
gliding
Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word ''soaring'' is al ...
called
dynamic soaring
Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary between air masses of different velocity. Such zones of wind gradient are generally found close to obstacles and close to the surface, so the technique is ...
(where the wind deflected by waves provides lift) as well as slope soaring. Seabirds also almost always have
webbed feet
The webbed foot is a specialized limb with interdigital membranes (webbings) that aids in aquatic locomotion, present in a variety of tetrapod vertebrates. This adaptation is primarily found in semiaquatic species, and has convergently evolved m ...
, to aid movement on the surface as well as assisting diving in some species. The
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, the petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still called tubenoses in English, procellariiforms are of ...
are unusual among birds in having a strong
sense of smell
The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste.
In humans, it ...
, which is used to find widely distributed food in a vast ocean, and help distinguish familiar nest odours from unfamiliar ones.
Salt glands
The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptiles ...
are used by seabirds to deal with the
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
they ingest by drinking and feeding (particularly on
crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s), and to help them osmoregulate.Harrison, C. S. (1990) ''Seabirds of Hawaii, Natural History and Conservation'' Ithaca:Cornell University Press, The
excretion
Excretion is a process in which metabolic waste
is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after lea ...
s from these glands (which are positioned in the head of the birds, emerging from the
nasal cavity
The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal c ...
) are almost pure
sodium chloride
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
.
With the exception of the
cormorant
Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...
s and some terns, and in common with most other birds, all seabirds have waterproof
plumage
Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
. However, compared to land birds, they have far more feathers protecting their bodies. This dense plumage is better able to protect the bird from getting wet, and cold is kept out by a dense layer of
down feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator an ...
s. The cormorants possess a layer of unique feathers that retain a smaller layer of air (compared to other diving birds) but otherwise soak up water. This allows them to swim without fighting the
buoyancy
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the p ...
that retaining air in the feathers causes, yet retain enough air to prevent the bird losing excessive heat through contact with water.
The plumage of most seabirds is less colourful than that of land birds, restricted in the main to variations of black, white or grey. A few species sport colourful plumes (such as the tropicbirds and some penguins), but most of the colour in seabirds appears in the bills and legs. The plumage of seabirds is thought in many cases to be for
camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
, both defensive (the colour of
US Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...
battleship
A battleship is a large armored warship with a main battery consisting of large caliber guns. It dominated naval warfare in the late 19th and early 20th centuries.
The term ''battleship'' came into use in the late 1880s to describe a type of ...
s is the same as that of
Antarctic prion
The Antarctic prion (''Pachyptila desolata'') also known as the dove prion, or totorore in Māori, is the largest of the prions, a genus of small petrels of the Southern Ocean.
Taxonomy
The Antarctic prion was formally described in 1789 by ...
s, and in both cases it reduces visibility at sea) and aggressive (the white underside possessed by many seabirds helps hide them from prey below). The usually black wing tips help prevent wear, as they contain melanins to make them black that helps the feathers resist abrasion.
Diet and feeding
Seabirds evolved to exploit different food resources in the world's seas and oceans, and to a great extent, their
physiology
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...
and
behaviour
Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as wel ...
have been shaped by their
diet
Diet may refer to:
Food
* Diet (nutrition), the sum of the food consumed by an organism or group
* Dieting, the deliberate selection of food to control body weight or nutrient intake
** Diet food, foods that aid in creating a diet for weight loss ...
. These evolutionary forces have often caused species in different families and even orders to evolve similar strategies and adaptations to the same problems, leading to remarkable
convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
, such as that between auks and penguins. There are four basic feeding strategies, or ecological guilds, for feeding at sea: surface feeding, pursuit diving, plunge-diving, and predation of
higher vertebrates
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are distingu ...
; within these guilds, there are multiple variations on the theme.
Surface feeding
Many seabirds feed on the ocean's surface, as the action of marine
currents
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (stre ...
often concentrates food such as
krill
Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian
Norwegian, Norwayan, or Norsk may refer to:
*Something of, from, or related to Norway, a country in n ...
,
forage fish
Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food ...
,
squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
, or other prey items within reach of a dipped head.
Surface feeding itself can be broken up into two different approaches, surface feeding while flying (for example as practiced by
gadfly petrel
The gadfly petrels or ''Pterodroma'' are a genus of about 35 species of petrels, part of the seabird order Procellariiformes. The gadfly petrels are named for their speedy weaving flight, as if evading gadflies (horseflies). The flight action is ...
s,
frigatebird
Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, long, deeply forked ...
s, and
storm petrel
Storm-petrel may refer to one of two bird families, both in the order Procellariiformes, once treated as the same family.
The two families are:
*Northern storm petrels (''Hydrobatidae'') are found in the Northern Hemisphere, although some species ...
s), and surface feeding while swimming (examples of which are practiced by
fulmar
The fulmars are tubenosed seabirds of the family Procellariidae. The family consists of two extant species and two extinct fossil species from the Miocene.
Fulmars superficially resemble gulls, but are readily distinguished by their flight on ...
s,
gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
s, many of the
shearwater
Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwa ...
s and gadfly petrels). Surface feeders in flight include some of the most acrobatic of seabirds, which either snatch morsels from the water (as do frigate-birds and some terns), or "walk", pattering and hovering on the water's surface, as some of the storm-petrels do. Many of these do not ever land in the water, and some, such as the frigatebirds, have difficulty getting airborne again should they do so. Another seabird family that does not land while feeding is the skimmer, which has a unique fishing method: flying along the surface with the lower mandible in the water—this shuts automatically when the bill touches something in the water. The skimmer's bill reflects its unusual lifestyle, with the lower mandible uniquely being longer than the upper one.
Surface feeders that swim often have unique bills as well, adapted for their specific prey.
Prions
Prions are misfolded proteins that have the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals. It i ...
have special bills with filters called
lamellae
Lamella (plural lamellae) means a small plate or flake in Latin, and in English may refer to:
Biology
* Lamella (mycology), a papery rib beneath a mushroom cap
* Lamella (botany)
* Lamella (surface anatomy), a plate-like structure in an animal
* ...
to filter out
plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...
from mouthfuls of water,Brooke, M. (2004). ''Albatrosses and Petrels Across the World''. Oxford University Press, Oxford, UK and many albatrosses and petrels have hooked bills to snatch fast-moving prey. On the other hand, most gulls are versatile and opportunistic feeders who will eat a wide variety of prey, both at sea and on land.
Pursuit diving
Pursuit diving exerts greater pressures (both evolutionary and physiological) on seabirds, but the reward is a greater area in which to feed than is available to surface feeders. Underwater
propulsion
Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived from ...
is provided by wings (as used by penguins, auks,
diving petrel
The diving petrels form a genus, ''Pelecanoides'', of seabirds in the family Procellariidae. There are four very similar species of diving petrels, distinguished only by small differences in the coloration of their plumage, habitat, and bill con ...
s and some other species of petrel) or
feet
The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...
(as used by cormorants,
grebe
Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably ...
s,
loon
Loons (North American English) or divers (British / Irish English) are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family Gaviidae and order Gavi ...
s and several types of fish-eating
duck
Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form t ...
s). Wing-propelled divers are generally faster than foot-propelled divers. The use of wings or feet for diving has limited their utility in other situations: loons and grebes walk with extreme difficulty (if at all), penguins cannot fly, and auks have sacrificed flight efficiency in favour of diving. For example, the
razorbill
The razorbill, razor-billed auk, or lesser auk (''Alca torda'') is a colonial seabird and the only extant member of the genus '' Alca'' of the family Alcidae, the auks. It is the closest living relative of the extinct great auk (''Pinguinis impe ...
(an Atlantic auk) requires 64% more energy to fly than a petrel of equivalent size.Gaston, Anthony J.; Jones, Ian L. (1998). ''The Auks'', Oxford University Press, Oxford, Many
shearwater
Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwa ...
s are intermediate between the two, having longer wings than typical wing-propelled divers but heavier wing loadings than the other surface-feeding procellariids, leaving them capable of diving to considerable depths while still being efficient long-distance travellers. The
short-tailed shearwater
The short-tailed shearwater or slender-billed shearwater (''Ardenna tenuirostris''; formerly ''Puffinus tenuirostris''), also called yolla or moonbird, and commonly known as the muttonbird in Australia, is the most abundant seabird species in A ...
is the deepest diver of the shearwaters, having been recorded diving below .
Some albatross species are also capable of limited diving, with
light-mantled sooty albatross
The light-mantled albatross (''Phoebetria palpebrata'') also known as the grey-mantled albatross or the light-mantled sooty albatross, is a small albatross in the genus '' Phoebetria'', which it shares with the sooty albatross. The light-mantle ...
es holding the record at . Of all the wing-propelled pursuit divers, the most efficient in the air are the albatrosses, and they are also the poorest divers. This is the dominant guild in polar and subpolar environments, but it is energetically inefficient in warmer waters. With their poor flying ability, many wing-propelled pursuit divers are more limited in their foraging range than other guilds.
Plunge diving
Gannet
Gannets are seabirds comprising the genus ''Morus'' in the family Sulidae, closely related to boobies.
Gannets are large white birds with yellowish heads; black-tipped wings; and long bills. Northern gannets are the largest seabirds in the ...
s,
boobies
A booby is a seabird in the genus ''Sula'', part of the family Sulidae. Boobies are closely related to the gannets (''Morus''), which were formerly included in ''Sula''.
Systematics and evolution
The genus ''Sula'' was introduced by the Fren ...
,
tropicbird
Tropicbirds are a family, Phaethontidae, of tropical pelagic seabirds. They are the sole living representatives of the order Phaethontiformes. For many years they were considered part of the Pelecaniformes, but genetics indicates they are most cl ...
s, some terns, and
brown pelican
The brown pelican (''Pelecanus occidentalis'') is a bird of the pelican family, Pelecanidae, one of three species found in the Americas and one of two that feed by diving into water. It is found on the Atlantic Coast from New Jersey to the mout ...
s all engage in plunge diving, taking fast-moving prey by diving into the water from the flight. Plunge diving allows birds to use the energy from the momentum of the dive to combat natural buoyancy (caused by air trapped in plumage), and thus uses less energy than the dedicated pursuit divers, allowing them to utilise more widely distributed food resources, for example, in impoverished
tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
seas. In general, this is the most specialised method of hunting employed by seabirds; other non-specialists (such as gulls and skuas) may employ it but do so with less skill and from lower heights. In brown pelicans the skills of plunge-diving take several years to fully develop—once mature, they can dive from 20 m (70 ft) above the water's surface, shifting the body before impact to avoid injury.
It may be that plunge divers are restricted in their hunting grounds to clear waters that afford a view of their prey from the air. While they are the dominant
guild
A guild ( ) is an association of artisans and merchants who oversee the practice of their craft/trade in a particular area. The earliest types of guild formed as organizations of tradesmen belonging to a professional association. They sometimes ...
in the tropics, the link between plunge diving and water clarity is inconclusive. Some plunge divers (as well as some surface feeders) are dependent on
dolphin
A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...
s and
tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...
to push shoaling fish up towards the surface.
Kleptoparasitism, scavenging and predation
This catch-all category refers to other seabird strategies that involve the next
trophic level
The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...
up. Kleptoparasites are seabirds that make a part of their living stealing food of other seabirds. Most famously,
frigatebird
Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, long, deeply forked ...
s and
skua
The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called jae ...
s engage in this behaviour, although gulls, terns and other species will steal food opportunistically. The
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
nesting behaviour of some seabirds has been interpreted as arising due to pressure from this aerial piracy. Kleptoparasitism is not thought to play a significant part of the diet of any species, and is instead a supplement to food obtained by hunting. A study of
great frigatebird
The great frigatebird (''Fregata minor'') is a large seabird in the frigatebird family. There are major nesting populations in the tropical Pacific (including the Galapagos Islands) and Indian Oceans, as well as a tiny population in the South At ...
s stealing from masked boobies estimated that the frigatebirds could at most obtain 40% of the food they needed, and on average obtained only 5%. Many species of gull will feed on seabird and sea mammal
carrion
Carrion () is the decaying flesh of dead animals, including human flesh.
Overview
Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...
when the opportunity arises, as will
giant petrel
Giant petrels form a genus, ''Macronectes'', from the family Procellariidae, which consists of two species. They are the largest birds of this family. Both species are restricted to the Southern Hemisphere, and though their distributions overlap ...
s. Some species of albatross also engage in scavenging: an analysis of regurgitated
squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
beaks has shown that many of the squid eaten are too large to have been caught alive, and include mid-water species likely to be beyond the reach of albatrosses. Some species will also feed on other seabirds; for example, gulls, skuas and pelicans will often take eggs, chicks and even small adult seabirds from nesting colonies, while the giant petrels can kill prey up to the size of small penguins and seal pups.
Life history
Seabirds' life histories are dramatically different from those of land birds. In general, they are
K-selected
In ecology, ''r''/''K'' selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of indivi ...
, live much longer (anywhere between twenty and sixty years), delay breeding for longer (for up to ten years), and invest more effort into fewer young. Most species will only have one
clutch
A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
a year, unless they lose the first (with a few exceptions, like the
Cassin's auklet
Cassin's auklet (''Ptychoramphus aleuticus'') is a small, chunky seabird that ranges widely in the North Pacific. It is the only species placed in the genus ''Ptychoramphus''. It nests in small burrows and because of its presence on well studied ...
), and many species (like the tubenoses and sulids) will only lay one egg a year.
Care of young is protracted, extending for as long as six months, among the longest for birds. For example, once
common guillemot
The common murre or common guillemot (''Uria aalge'') is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land to ...
chicks
fledge
Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight.
This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable c ...
, they remain with the male parent for several months at sea. The frigatebirds have the longest period of parental care of any bird except a few raptors and the
southern ground hornbill
The southern ground hornbill (''Bucorvus leadbeateri''; formerly known as ''Bucorvus cafer'') is one of two species of ground hornbill, both of which are found solely within Africa, and is the largest species in the hornbill order worldwide. It ...
, with each chick fledging after four to six months and continued assistance after that for up to fourteen months. Due to the extended period of care, breeding occurs every two years rather than annually for some species. This life-history strategy has probably evolved both in response to the challenges of living at sea (collecting widely scattered prey items), the frequency of breeding failures due to unfavourable marine conditions, and the relative lack of predation compared to that of land-living birds.
Because of the greater investment in raising the young and because foraging for food may occur far from the nest site, in all seabird species except the phalaropes, both parents participate in caring for the young, and pairs are typically at least seasonally
monogamous
Monogamy ( ) is a form of Dyad (sociology), dyadic Intimate relationship, relationship in which an individual has only one Significant other, partner during their lifetime. Alternately, only one partner at any one time (Monogamy#Serial monogamy, ...
. Many species, such as gulls, auks and penguins, retain the same mate for several seasons, and many
petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes.
Description
The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross f ...
species mate for life. Albatrosses and procellariids, which mate for life, take many years to form a pair bond before they breed, and the albatrosses have an elaborate breeding dance that is part of pair-bond formation.
Breeding and colonies
Ninety-five percent of seabirds are colonial, and seabird colonies are among the largest bird colonies in the world, providing one of Earth's great wildlife spectacles. Colonies of over a million birds have been recorded, both in the tropics (such as
Kiritimati
Kiritimati (also known as Christmas Island) is a Pacific Ocean atoll in the northern Line Islands. It is part of the Republic of Kiribati. The name is derived from the English word "Christmas" written in Gilbertese according to its phonolog ...
in the
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
) and in the polar latitudes (as in
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
). Seabird colonies occur exclusively for the purpose of breeding; non-breeding birds will only collect together outside the breeding season in areas where prey species are densely aggregated.
Seabird colonies are highly variable. Individual nesting sites can be widely spaced, as in an albatross colony, or densely packed as with a
murre
''Uria'' is a genus of seabirds in the auk family known in Britain as guillemots, in most of North America as murres, and in Newfoundland and Labrador as turr. These are medium-sized birds with mainly brown or black plumage in the breeding sea ...
colony. In most seabird colonies, several different species will nest on the same colony, often exhibiting some
niche separation
In ecology, niche differentiation (also known as niche segregation, niche separation and niche partitioning) refers to the process by which competing species use the environment differently in a way that helps them to coexist. The competitive exc ...
. Seabirds can nest in trees (if any are available), on the ground (with or without
nests
A nest is a structure built for certain animals to hold eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic materi ...
), on cliffs, in
burrow
An Eastern chipmunk at the entrance of its burrow
A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of sh ...
s under the ground and in rocky crevices. Competition can be strong both within species and between species, with aggressive species such as
sooty tern
The sooty tern (''Onychoprion fuscatus'') is a seabird in the family Laridae. It is a bird of the tropical oceans, returning to land only to breed on islands throughout the equatorial zone.
Taxonomy
The sooty tern was described by Carl Linnaeu ...
s pushing less dominant species out of the most desirable nesting spaces. The tropical
Bonin petrel
The Bonin petrel or'' nunulu'' (''Pterodroma hypoleuca'') is a seabird in the family Procellariidae. It is a small gadfly petrel that is found in the northwest Pacific Ocean. Its secretive habits, remote breeding colonies and limited range have re ...
nests during the winter to avoid competition with the more aggressive
wedge-tailed shearwater
The wedge-tailed shearwater (''Ardenna pacifica'') is a medium-large shearwater in the seabird family Procellariidae. It is one of the shearwater species that is sometimes referred to as a muttonbird, like the sooty shearwater of New Zealand and ...
. When the seasons overlap, the wedge-tailed shearwaters will kill young Bonin petrels in order to use their burrows.
Many seabirds show remarkable site
fidelity
Fidelity is the quality of faithfulness or loyalty. Its original meaning regarded duty in a broader sense than the related concept of ''fealty''. Both derive from the Latin word ''fidēlis'', meaning "faithful or loyal". In the City of London f ...
, returning to the same burrow, nest or site for many years, and they will defend that site from rivals with great vigour. This increases breeding success, provides a place for returning mates to reunite, and reduces the costs of prospecting for a new site. Young adults breeding for the first time usually return to their natal colony, and often nest close to where they hatched. This tendency, known as
philopatry
Philopatry is the tendency of an organism to stay in or habitually return to a particular area. The causes of philopatry are numerous, but natal philopatry, where animals return to their birthplace to breed, may be the most common. The term derives ...
, is so strong that a study of
Laysan albatross
The Laysan albatross (''Phoebastria immutabilis'') is a large seabird that ranges across the North Pacific. The Northwestern Hawaiian Islands are home to 99.7% of the population. This small (for its family) gull-like albatross is the second-most ...
es found that the average distance between hatching site and the site where a bird established its own territory was ; another study, this time on
Cory's shearwater
Cory's shearwater (''Calonectris borealis'') is a large shearwater in the seabird family Procellariidae. It breeds colonially of rocky islands in the eastern Atlantic. Outside the breeding season it ranges widely in the Atlantic. It was formerl ...
s nesting near
Corsica
Corsica ( , Upper , Southern ; it, Corsica; ; french: Corse ; lij, Còrsega; sc, Còssiga) is an island in the Mediterranean Sea and one of the 18 regions of France. It is the fourth-largest island in the Mediterranean and lies southeast of ...
, found that of nine out of 61 male chicks that returned to breed at their natal colony bred in the burrow they were raised in, and two actually bred with their own mother.
Colonies are usually situated on islands, cliffs or headlands, which land mammals have difficulty accessing.Moors, P. J.; Atkinson, I. A. E. (1984). ''Predation on seabirds by introduced animals, and factors affecting its severity''. In ''Status and Conservation of the World's Seabirds''. Cambridge: ICBP. This is thought to provide protection to seabirds, which are often very clumsy on land. Coloniality often arises in types of bird that do not defend feeding territories (such as
swift
Swift or SWIFT most commonly refers to:
* SWIFT, an international organization facilitating transactions between banks
** SWIFT code
* Swift (programming language)
* Swift (bird), a family of birds
It may also refer to:
Organizations
* SWIFT, ...
s, which have a very variable prey source); this may be a reason why it arises more frequently in seabirds. There are other possible advantages: colonies may act as information centres, where seabirds returning to the sea to forage can find out where prey is by studying returning individuals of the same species. There are disadvantages to colonial life, particularly the spread of disease. Colonies also attract the attention of
predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
, principally other birds, and many species attend their colonies nocturnally to avoid predation. Birds from different colonies often forage in different areas to avoid competition.
breeding season
Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and cha ...
. Of these, the trip taken by the
Arctic tern
The Arctic tern (''Sterna paradisaea'') is a tern in the family Laridae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe (as far south as Brittany), Asia, and North America (as far south a ...
is the farthest of any bird, crossing the
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
in order to spend the Austral summer in Antarctica. Other species also undertake trans-equatorial trips, both from the north to the south, and from south to north. The population of
elegant tern
The elegant tern (''Thalasseus elegans'') is a tern in the family Laridae. It breeds on the Pacific coasts of the southern United States and Mexico and winters south to Peru, Ecuador and Chile.
This species breeds in very dense colonies on coa ...
s, which nest off
Baja California
Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
, splits after the breeding season with some birds travelling north to the
Central Coast of California
The Central Coast is an area of California, roughly spanning the coastal region between Point Mugu and Monterey Bay. It lies northwest of Los Angeles County and south of San Mateo and Santa Clara counties, and includes the rugged, undevelope ...
and some travelling as far south as Peru and Chile to feed in the
Humboldt Current
The Humboldt Current, also called the Peru Current, is a cold, low- salinity ocean current that flows north along the western coast of South America.Montecino, Vivian, and Carina B. Lange. "The Humboldt Current System: Ecosystem components and pr ...
. The
sooty shearwater
The sooty shearwater (''Ardenna grisea'') is a medium-large shearwater in the seabird family Procellariidae. In New Zealand, it is also known by its Māori name , and as muttonbird, like its relatives the wedge-tailed shearwater (''A. pacificus' ...
undertakes an annual migration cycle that rivals that of the Arctic tern; birds that nest in New Zealand and Chile and spend the northern summer feeding in the North Pacific off Japan, Alaska and California, an annual round trip of .
Other species also migrate shorter distances away from the breeding sites, their distribution at sea determined by the availability of food. If oceanic conditions are unsuitable, seabirds will emigrate to more productive areas, sometimes permanently if the bird is young. After fledging, juvenile birds often disperse further than adults, and to different areas, so are commonly sighted far from a species' normal range. Some species, such as the auks, do not have a concerted migration effort, but drift southwards as the winter approaches. Other species, such as some of the storm petrels, diving petrels and cormorants, never disperse at all, staying near their breeding colonies year round.
Away from the sea
While the definition of seabirds suggests that the birds in question spend their lives on the ocean, many seabird families have many species that spend some or even most of their lives inland away from the sea. Most strikingly, many species breed tens, hundreds or even thousands of miles inland. Some of these species still return to the ocean to feed; for example, the
snow petrel
The snow petrel (''Pagodroma nivea'') is the only member of the genus ''Pagodroma.'' It is one of only three birds that has been seen at the Geographic South Pole, along with the Antarctic petrel and the south polar skua, which have the most so ...
, the nests of which have been found inland on the Antarctic mainland, are unlikely to find anything to eat around their breeding sites. The marbled murrelet nests inland in
old growth forest
An old-growth forestalso termed primary forest, virgin forest, late seral forest, primeval forest, or first-growth forestis a forest that has attained great age without significant disturbance, and thereby exhibits unique ecological featur ...
, seeking huge
conifer
Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...
s with large branches to nest on. Other species, such as the
California gull
The California gull (''Larus californicus'') is a medium-sized gull, smaller on average than the herring gull but larger on average than the ring-billed gull, though it may overlap in size greatly with both.
Description
Adults are similar in ap ...
, nest and feed inland on lakes, and then move to the coasts in the winter. Some cormorant,
pelican
Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before s ...
, gull and tern species have individuals that never visit the sea at all, spending their lives on lakes, rivers,
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s and, in the case of some of the gulls, cities and
agricultural
Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
land. In these cases it is thought that these terrestrial or freshwater birds evolved from marine ancestors. Some seabirds, principally those that nest in
tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless moun ...
, as skuas and phalaropes do, will migrate over land as well.
The more marine species, such as petrels, auks and
gannet
Gannets are seabirds comprising the genus ''Morus'' in the family Sulidae, closely related to boobies.
Gannets are large white birds with yellowish heads; black-tipped wings; and long bills. Northern gannets are the largest seabirds in the ...
s, are more restricted in their habits, but are occasionally seen inland as vagrants. This most commonly happens to young inexperienced birds, but can happen in great numbers to exhausted adults after large
storm
A storm is any disturbed state of the natural environment or the atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmos ...
s, an event known as a ''wreck''.
Relationship with humans
Seabirds and fisheries
Seabirds have had a long association with both
fisheries
Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...
and
sailor
A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship.
The profession of the s ...
s, and both have drawn benefits and disadvantages from the relationship.
Fishermen have traditionally used seabirds as indicators of both fish shoals, underwater
banks
A bank is a financial institution that accepts deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital markets.
Becaus ...
that might indicate fish stocks, and of potential landfall. In fact, the known association of seabirds with land was instrumental in allowing the
Polynesia
Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...
ns to locate tiny landmasses in the Pacific. Seabirds have provided food for fishermen away from home, as well as bait. Famously, tethered cormorants have been used to catch fish directly. Indirectly, fisheries have also benefited from
guano
Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...
from colonies of seabirds acting as
fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
for the surrounding seas.
Negative effects on fisheries are mostly restricted to raiding by birds on
aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
, although
long-lining
Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.bait stealing. There have been claims of prey depletion by seabirds of fishery stocks, and while there is some evidence of this, the effects of seabirds are considered smaller than that of
marine mammal
Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reli ...
s and predatory fish (like
tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...
).Some seabird species have benefited from fisheries, particularly from discarded fish and
offal
Offal (), also called variety meats, pluck or organ meats, is the organs of a butchered animal. The word does not refer to a particular list of edible organs, which varies by culture and region, but usually excludes muscle. Offal may also refe ...
. These discards compose 30% of the food of seabirds in the
North Sea
The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...
, for example, and compose up to 70% of the total food of some seabird populations. This can have other impacts; for example, the spread of the
northern fulmar
The northern fulmar (''Fulmarus glacialis''), fulmar, or Arctic fulmar is a highly abundant seabird found primarily in subarctic regions of the North Atlantic and North Pacific oceans. There has been one confirmed sighting in the Southern Hem ...
through the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
is attributed in part to the availability of discards. Discards generally benefit surface feeders, such as gannets and petrels, to the detriment of pursuit divers like penguins and guillemots, which can get entangled in the nets.
Fisheries also have negative effects on seabirds, and these effects, particularly on the long-lived and slow-breeding albatrosses, are a source of increasing concern to conservationists. The bycatch of seabirds entangled in nets or hooked on fishing lines has had a big impact on seabird numbers; for example, an estimated 100,000 albatrosses are hooked and drown each year on tuna lines set out by long-line fisheries. Overall, many hundreds of thousands of birds are trapped and killed each year, a source of concern for some of the rarest species (for example, only about 2,000
short-tailed albatross
The short-tailed albatross or Steller's albatross (''Phoebastria albatrus'') is a large rare seabird from the North Pacific. Although related to the other North Pacific albatrosses, it also exhibits behavioural and morphological links to the alb ...
es are known to still exist). Seabirds are also thought to suffer when overfishing occurs. Changes to the marine ecosystems caused by dredging, which alters the biodiversity of the seafloor, can also have a negative impact.
Exploitation
The
hunting
Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...
of seabirds and the collecting of seabird
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
have contributed to the declines of many species, and the
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
ion of several, including the
great auk
The great auk (''Pinguinus impennis'') is a species of flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus ''Pinguinus''. It is not closely related to the birds now known as penguins, wh ...
and the spectacled cormorant. Seabirds have been hunted for food by coastal peoples throughout history—one of the earliest instances known is in southern Chile, where
archaeological
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...
excavations in middens has shown hunting of albatrosses, cormorants and shearwaters from 5000 BP. This pressure has led to some species becoming extinct in many places; in particular, at least 20 species of an original 29 no longer breed on
Easter Island
Easter Island ( rap, Rapa Nui; es, Isla de Pascua) is an island and special territory of Chile in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle in Oceania. The island is most famous for its nearl ...
. In the 19th century, the hunting of seabirds for
fat
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers spec ...
deposits and feathers for the
millinery
Hat-making or millinery is the design, manufacture and sale of hats and other headwear. A person engaged in this trade is called a milliner or hatter.
Historically, milliners, typically women shopkeepers, produced or imported an inventory of g ...
trade reached industrial levels.
Muttonbirding
Muttonbirding is the seasonal harvesting of the chicks of petrels, especially shearwater species, for food, oil and feathers by recreational or commercial hunters. Such hunting of petrels and other seabirds has occurred in various locations since p ...
(harvesting shearwater chicks) developed as important industries in both New Zealand and Tasmania, and the name of one species, the providence petrel, is derived from its seemingly miraculous arrival on
Norfolk Island
Norfolk Island (, ; Norfuk: ''Norf'k Ailen'') is an external territory of Australia located in the Pacific Ocean between New Zealand and New Caledonia, directly east of Australia's Evans Head and about from Lord Howe Island. Together with ...
where it provided a windfall for starving European settlers. In the
Falkland Islands
The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubouzet ...
, hundreds of thousands of penguins were harvested for their oil each year. Seabird eggs have also long been an important source of food for sailors undertaking long sea voyages, as well as being taken when settlements grow in areas near a colony. Eggers from
San Francisco
San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
took almost half a million eggs a year from the
Farallon Islands
The Farallon Islands, or Farallones (from the Spanish ''farallón'' meaning "pillar" or "sea cliff"), are a group of islands and sea stacks in the Gulf of the Farallones, off the coast of San Francisco, California, United States. The island ...
in the mid-19th century, a period in the islands' history from which the seabird species are still recovering.
Both hunting and egging continue today, although not at the levels that occurred in the past, and generally in a more controlled manner. For example, the
Māori
Māori or Maori can refer to:
Relating to the Māori people
* Māori people of New Zealand, or members of that group
* Māori language, the language of the Māori people of New Zealand
* Māori culture
* Cook Islanders, the Māori people of the C ...
of
Stewart Island/Rakiura
Stewart Island ( mi, Rakiura, ' glowing skies', officially Stewart Island / Rakiura) is New Zealand's third-largest island, located south of the South Island, across the Foveaux Strait. It is a roughly triangular island with a total land ar ...
continue to harvest the chicks of the sooty shearwater as they have done for centuries, using traditional stewardship, ''
kaitiaki
Kaitiaki is a New Zealand Māori term used for the concept of guardianship, for the sky, the sea, and the land. A kaitiaki is a guardian, and the process and practices of protecting and looking after the environment are referred to as kaitiakita ...
tanga'', to manage the harvest, but now also work with the
University of Otago
, image_name = University of Otago Registry Building2.jpg
, image_size =
, caption = University clock tower
, motto = la, Sapere aude
, mottoeng = Dare to be wise
, established = 1869; 152 years ago
, type = Public research collegiate u ...
in studying the populations. In
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
, however, uncontrolled hunting is pushing many species into steep decline.
Other threats
Other human factors have led to declines and even extinctions in seabird populations and species. Of these, perhaps the most serious are
introduced species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
. Seabirds, breeding predominantly on small isolated islands, are vulnerable to predators because they have lost many behaviours associated with defence from predators.
Feral cat
A feral cat or a stray cat is an unowned domestic cat (''Felis catus'') that lives outdoors and avoids human contact: it does not allow itself to be handled or touched, and usually remains hidden from humans. Feral cats may breed over dozens ...
s can take seabirds as large as albatrosses, and many introduced rodents, such as the
Pacific rat
The Polynesian rat, Pacific rat or little rat (''Rattus exulans''), known to the Māori as ''kiore'', is the third most widespread species of rat in the world behind the brown rat and black rat. The Polynesian rat originated in Southeast Asia, a ...
, take eggs hidden in burrows. Introduced goats, cattle, rabbits and other
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s can create problems, particularly when species need vegetation to protect or shade their young. The disturbance of breeding colonies by humans is often a problem as well—visitors, even well-meaning tourists, can flush brooding adults off a colony, leaving chicks and eggs vulnerable to predators.
The build-up of
toxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849– ...
s and pollutants in seabirds is also a concern. Seabirds, being
apex predator
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
s, suffered from the ravages of the insecticide
DDT
Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
until it was banned; DDT was implicated, for example, in embryo development problems and the skewed sex ratio of
western gull
The western gull (''Larus occidentalis'') is a large white-headed gull that lives on the west coast of North America. It was previously considered conspecific with the yellow-footed gull (''Larus livens'') of the Gulf of California. The western g ...
s in southern California.
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s are also a threat to seabirds: the oil is toxic, and bird feathers become saturated by the oil, causing them to lose their waterproofing. Oil pollution in particular threatens species with restricted ranges or already depressed populations.
Climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
mainly affect seabirds via changes to their
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
: various processes in the ocean lead to decreased availability of food and colonies are more often flooded as a consequence of
sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
and extreme rainfall events. Heat stress from extreme temperatures is an additional threat. Some seabirds have used changing wind patterns to forage further and more efficiently.
Conservation
The threats faced by seabirds have not gone unnoticed by scientists or the
conservation movement
The conservation movement, also known as nature conservation, is a political, environmental, and social movement that seeks to manage and protect natural resources, including animal, fungus, and plant species as well as their habitat for the f ...
. As early as 1903, U.S. President
Theodore Roosevelt
Theodore Roosevelt Jr. ( ; October 27, 1858 – January 6, 1919), often referred to as Teddy or by his initials, T. R., was an American politician, statesman, soldier, conservationist, naturalist, historian, and writer who served as the 26t ...
was convinced of the need to declare Pelican Island in Florida a
National Wildlife Refuge
National Wildlife Refuge System is a designation for certain protected areas of the United States managed by the United States Fish and Wildlife Service. The National Wildlife Refuge System is the system of public lands and waters set aside to c ...
to protect the bird colonies (including the nesting
brown pelican
The brown pelican (''Pelecanus occidentalis'') is a bird of the pelican family, Pelecanidae, one of three species found in the Americas and one of two that feed by diving into water. It is found on the Atlantic Coast from New Jersey to the mout ...
s), and in 1909 he protected the Farallon Islands. Today many important seabird colonies are given some measure of protection, from Heron Island in Australia to
Triangle Island
Triangle Island is a small island, approximately in area,Anne Vallee Triangle Island Ecological Reserve Purpose Statement Ministry of Environmen/ref> located off the northwestern tip of Vancouver Island, British Columbia, Canada. It is situated ap ...
in British Columbia.
Island restoration
The ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as ...
techniques, pioneered by New Zealand, enable the removal of exotic invaders from increasingly large islands. Feral cats have been removed from Ascension Island,
Arctic fox
The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in co ...
es from many islands in the
Aleutian Islands
The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi language, Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a cha ...
, and rats from Campbell Island. The removal of these introduced species has led to increases in numbers of species under pressure and even the return of extirpated ones. After the removal of cats from Ascension Island, seabirds began to nest there again for the first time in over a hundred years.
Seabird mortality caused by long-line fisheries can be greatly reduced by techniques such as setting long-line bait at night, dying the bait blue, setting the bait underwater, increasing the amount of weight on lines and by using bird scarers, and their deployment is increasingly required by many national fishing fleets.
One of the Millennium Projects in the UK was the Scottish Seabird Centre, near the important bird sanctuaries on
Bass Rock
The Bass Rock, or simply the Bass (), ( gd, Creag nam Bathais or gd, Am Bas) is an island in the outer part of the Firth of Forth in the east of Scotland. Approximately offshore, and north-east of North Berwick, it is a steep-sided volcan ...
,
Fidra
Fidra (archaically Fidrey or Fetheray) is a currently uninhabited island in the Firth of Forth, northwest of North Berwick, on the east coast of Scotland. The island is an RSPB Scotland nature reserve.
Geography
Like the other islands near N ...
and the surrounding islands. The area is home to huge colonies of gannets,
puffin
Puffins are any of three species of small alcids (auks) in the bird genus ''Fratercula''. These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crev ...
s, skuas and other seabirds. The centre allows visitors to watch live video from the islands as well as learn about the threats the birds face and how we can protect them, and has helped to significantly raise the profile of seabird conservation in the UK. Seabird tourism can provide income for coastal communities as well as raise the profile of seabird conservation, although it needs to be managed to ensure it does not harm the colonies and nesting birds. For example, the
northern royal albatross
The northern royal albatross or toroa, (''Diomedea sanfordi''), is a large seabird in the albatross family. It was split from the closely related southern royal albatross as recently as 1998, though not all scientists support that conclusion and ...
colony at
Taiaroa Head
Taiaroa Head is a headland at the end of the Otago Peninsula in New Zealand, overlooking the mouth of the Otago Harbour. It lies within the city limits of Dunedin. The nearest settlement, Otakou, lies three kilometres to the south.
The cape is h ...
in New Zealand attracts 40,000 visitors a year.
The plight of albatross and large seabirds, as well as other marine creatures, being taken as bycatch by long-line fisheries, has been addressed by a large number of
non-governmental organization
A non-governmental organization (NGO) or non-governmental organisation (see spelling differences) is an organization that generally is formed independent from government. They are typically nonprofit entities, and many of them are active in h ...
s (including
BirdLife International
BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding ...
, the
American Bird Conservancy
American Bird Conservancy (ABC) is a non-profit membership organization with the mission of conserving wild birds and their habitats throughout the Americas. Its focus is on threats to birds in the Western Hemisphere – threats which include ov ...
and the
Royal Society for the Protection of Birds
The Royal Society for the Protection of Birds (RSPB) is a charitable organisation registered in England and Wales and in Scotland. It was founded in 1889. It works to promote conservation and protection of birds and the wider environment throug ...
). This led to the
Agreement on the Conservation of Albatrosses and Petrels
The Agreement on the Conservation of Albatrosses and Petrels (ACAP) is a legally binding international agreement signed in 2001 and entered into force on 1 February 2004 when South Africa ratified as the fifth Party to the Agreement.
It was crea ...
, a legally binding treaty designed to protect these threatened species, which has been ratified by thirteen countries as of 2021 (Argentina, Australia, Brazil, Chile, Ecuador, France, New Zealand, Norway, Peru, South Africa, Spain, Uruguay, United Kingdom).
Role in culture
Many seabirds are little studied and poorly known because they live far out at sea and breed in isolated colonies. Some seabirds, particularly the albatrosses and gulls, are more well known to humans. The albatross has been described as "the most legendary of birds", and have a variety of myths and legends associated with them. While it is widely considered unlucky to harm them, the notion that sailors believed that is a myth that derives from
Samuel Taylor Coleridge
Samuel Taylor Coleridge (; 21 October 177225 July 1834) was an English poet, literary critic, philosopher, and theologian who, with his friend William Wordsworth, was a founder of the Romantic Movement in England and a member of the Lake Poe ...
's famous poem, "
The Rime of the Ancient Mariner
''The Rime of the Ancient Mariner'' (originally ''The Rime of the Ancyent Marinere'') is the longest major poem by the English poet Samuel Taylor Coleridge, written in 1797–1798 and published in 1798 in the first edition of ''Lyrical Ballad ...
", in which a sailor is punished for killing an albatross by having to wear its corpse around his neck. Sailors did, however, consider it unlucky to touch a storm petrel, especially one that landed on the ship.
Gulls are one of the most commonly seen seabirds because they frequent human-made habitats (such as cities and dumps) and often show a fearless nature. Gulls have been used as metaphors, as in ''
Jonathan Livingston Seagull
''Jonathan Livingston Seagull'', written by American author Richard Bach and illustrated with black-and-white photographs shot by Russell Munson, is a fable in novella form about a seagull who is trying to learn about life and flight, and a homi ...
'' by
Richard Bach
Richard David Bach (born June 23, 1936) is an American writer. He has written numerous works of fiction and also non-fiction flight-related titles. His works include ''Jonathan Livingston Seagull'' (1970) and '' Illusions: The Adventures of a R ...
, or to denote a closeness to the sea; in ''
The Lord of the Rings
''The Lord of the Rings'' is an epic high-fantasy novel by English author and scholar J. R. R. Tolkien. Set in Middle-earth, intended to be Earth at some time in the distant past, the story began as a sequel to Tolkien's 1937 children's boo ...
'', they appear in the insignia of
Gondor
Gondor is a fictional kingdom in J. R. R. Tolkien's writings, described as the greatest realm of Man (Middle-earth), Men in the west of Middle-earth at the end of the Third Age. The third volume of ''The Lord of the Rings'', ''The Return of the ...
and therefore
Númenor
Númenor, also called Elenna-nórë or Westernesse, is a fictional place in J. R. R. Tolkien's writings. It was the kingdom occupying a large island to the west of Middle-earth, the main setting of Tolkien's writings, and was the greatest civil ...
(used in the design of the films), and they call
Legolas
Legolas (pronounced ) is a fictional character in J. R. R. Tolkien's ''The Lord of the Rings''. He is a Sindar Elf of the Woodland Realm and one of the nine members of the Fellowship who set out to destroy the One Ring. He and the Dwarf Gimli ...
to (and across) the sea. Pelicans have long been associated with mercy and
altruism
Altruism is the principle and moral practice of concern for the welfare and/or happiness of other human beings or animals, resulting in a quality of life both material and spiritual. It is a traditional virtue in many cultures and a core as ...
because of an early
Christian
Christians () are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words ''Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χρι ...
myth that they split open their breast to feed their starving chicks.
Seabird families
The following are the groups of birds normally classed as seabirds.
Sphenisciformes
Penguins ( order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapt ...
(Antarctic and southern waters; 16 species)
* Spheniscidae
penguin
Penguins (order (biology), order List of Sphenisciformes by population, Sphenisciformes , family (biology), family Spheniscidae ) are a group of Water bird, aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: on ...
s
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, the petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still called tubenoses in English, procellariiforms are of ...
(Tubenoses: pan-oceanic and pelagic; 93 species)
* Diomedeidae
albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Pacifi ...
es
* Procellariidae
fulmar
The fulmars are tubenosed seabirds of the family Procellariidae. The family consists of two extant species and two extinct fossil species from the Miocene.
Fulmars superficially resemble gulls, but are readily distinguished by their flight on ...
s,
prions
Prions are misfolded proteins that have the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals. It i ...
,
shearwater
Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwa ...
petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes.
Description
The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross f ...
s
* Pelacanoididae
diving petrel
The diving petrels form a genus, ''Pelecanoides'', of seabirds in the family Procellariidae. There are four very similar species of diving petrels, distinguished only by small differences in the coloration of their plumage, habitat, and bill con ...
s
* Hydrobatidae
storm petrel
Storm-petrel may refer to one of two bird families, both in the order Procellariiformes, once treated as the same family.
The two families are:
*Northern storm petrels (''Hydrobatidae'') are found in the Northern Hemisphere, although some species ...
s
Pelecaniformes
The Pelecaniformes are an order of medium-sized and large waterbirds found worldwide. As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such ...
(Worldwide; 8 species)
* Pelecanidae
pelican
Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before s ...
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Suliformes
The order Suliformes (, dubbed "Phalacrocoraciformes" by ''Christidis & Boles 2008'') is an order recognised by the International Ornithological Congress, International Ornithologist's Union. In regard to the recent evidence that the traditional ...
(Worldwide; about 56 species)
* Sulidae
gannet
Gannets are seabirds comprising the genus ''Morus'' in the family Sulidae, closely related to boobies.
Gannets are large white birds with yellowish heads; black-tipped wings; and long bills. Northern gannets are the largest seabirds in the ...
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boobies
A booby is a seabird in the genus ''Sula'', part of the family Sulidae. Boobies are closely related to the gannets (''Morus''), which were formerly included in ''Sula''.
Systematics and evolution
The genus ''Sula'' was introduced by the Fren ...
* Phalacrocoracidae
cormorant
Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...
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* Fregatidae
frigatebird
Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, long, deeply forked ...
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Phaethontiformes
The Phaethontiformes are an order of birds. They contain one extant family, the tropicbirds (Phaethontidae), and one extinct family Prophaethontidae from the early Cenozoic. Several fossil genera have been described.
The tropicbirds were tradit ...
tropicbird
Tropicbirds are a family, Phaethontidae, of tropical pelagic seabirds. They are the sole living representatives of the order Phaethontiformes. For many years they were considered part of the Pelecaniformes, but genetics indicates they are most cl ...
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Charadriiformes
Charadriiformes (, from ''Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water an ...
(Worldwide; 305 species, but only the families listed are classed as seabirds.)
* Stercorariidae
skua
The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called jae ...
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* Laridae
gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
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* Sternidae
tern
Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...
auk
An auk or alcid is a bird of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The word "auk" is derived from Icelandic ''álka'', from Old Norse ''alka'' (a ...