The black skimmer (''Rynchops niger'') is a
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 ...
-like
seabird
Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...
, one of three similar birds species in the
skimmer genus ''Rynchops'' in the
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 ...
family Laridae. It breeds in
North
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography.
Etymology
The word ''north ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. Northern populations
winter
Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultur ...
in the warmer waters of the
Caribbean and the tropical and subtropical
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 contine ...
coasts, but the South American
races make only shorter movements in response to annual floods which extend their feeding areas in the river shallows.
Taxonomy
The black skimmer was described by the Swedish naturalist
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in 1755 in the
tenth edition of his ''
Systema Naturae'' and given the
binomial name ''Rynchops niger''. The genus name ''Rynchops'' is from the
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
ῥυγχος/''rhunkhos'' meaning "bill" and κοπτω/''koptō'' meaning "to cut off". The specific ''niger'' is the Latin word for "black". The black skimmer is one of three species in the genus ''Rynchops''.
[
There are three subspecies:]
*''R. n. niger'' (Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...
, 1758) – migratory, breeds on the Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
coast of North America, and from southern California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
to Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...
in the Pacific
*''R. n. cinerascens'' ( von Spix, 1825) – is larger, has dusky underwings, only narrow white fringe to its black tail, and breeds in northern and northeastern South America and the Amazon basin
*''R. n. intercedens'' (Saunders
Saunders is a surname of English and Scottish patronymic origin derived from Sander, a mediaeval form of Alexander.See also: Sander (name)
People
* Ab Saunders (1851–1883), American cowboy and gunman
* Al Saunders (born 1947), American foot ...
, 1895) – occurs on the rest of the Atlantic coast of South America south to central Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
Description
The black skimmer is the largest of the three skimmer species. It measures long with a wingspan. This species ranges from , with males averaging about , as compared to the smaller females .[''CRC Handbook of Avian Body Masses'' by John B. Dunning Jr. (Editor). CRC Press (1992), .] The basal half of the bill is red, the rest mainly black, and the lower mandible is much-elongated. The eye has a dark brown iris and cat
The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
like vertical pupil, unique for a bird. The legs are red. The call is a barking ''kak-kak-kak''.
Adults in breeding plumage have a black crown, nape and upper body. The forehead and underparts are white. The upper wings are black with white on the rear edge, and the tail and rump are dark grey with white edges. The underwing colour varies from white to dusky grey depending on region.[
Non-breeding adults have paler and browner upperparts, and a white nape collar. Immature birds have brown upperparts with white feather tips and fringes. The underparts and forehead are white, and the underwings as the adult.][
]
Behaviour and ecology
They spend much time loafing gregariously on sandbars in the rivers, coasts and lagoons they frequent.
Breeding
The black skimmer breeds in loose groups on sandbanks and sandy beaches in the Americas, the three to seven heavily dark-blotched buff or bluish eggs being incubated by both the male and female. The chicks leave the nest as soon as they hatch and lie inconspicuously in the nest depression or "scrape" where they are shaded from high temperatures by the parents. They may dig their own depressions in the sand at times. Parents feed the young almost exclusively during the day with almost no feeding occurring at night, due to the entire population of adults sometimes departing the colony to forage. Although the mandibles are of equal length at hatching, they rapidly become unequal during fledging.
Feeding
Skimmers have a light graceful flight, with steady beats of their long wings. They usually feed in large flocks, flying low over the water surface with the lower mandible skimming the water for (in order of importance) small fish, insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s, 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 can ...
s and molluscs caught by touch by day or especially at night.[ Fish species eaten include '' Odontesthes argentinenesis'', '']Brevoortia
Menhaden, also known as mossbunker and bunker and "the most important fish in the sea", are forage fish of the genera ''Brevoortia'' and ''Ethmidium'', two genera of marine fish in the family Clupeidae. ''Menhaden'' is a blend of ''poghaden'' ...
aurea'', '' Anchoa marinii'', ''Lycengraulis
''Lycengraulis'' is a genus of anchovies containing four recognized species. They are restricted to the Western Hemisphere in the waters in and around Central America and South America.
Species
There are currently five recognized species in this ...
grossidens'', '' Engraulis anchoita'', '' Pomatomus saltatrix'', ''Mugil cephalus
The flathead grey mullet (''Mugil cephalus'') is an important food fish species in the mullet family Mugilidae. It is found in coastal tropical and subtropical waters worldwide. Its length is typically . It is known with numerous English names ...
'', ''Fundulus heteroclitus
The mummichog (''Fundulus heteroclitus'') is a small killifish found along the Atlantic coast of the United States and Canada. Also known as Atlantic killifish, mummies, gudgeons, and mud minnows, these fish inhabit brackish and coastal waters in ...
'' and ''Anchoa mitchelli''.
Development
File:Rynchops niger1.jpg, Chick and egg
File:Black Skimmer and Chick by Dan Pancamo.jpg, Adult feeding a chick
File:Black Skimmer Chicks by Dan Pancamo.jpg, Juveniles at four weeks. They are distinguished from adults by the white speckled pattern on their wings and body.
File:Bec en ciseaux noir juvénile.jpg, Adult winter plumage
Notes
References
*
*
* ''A guide to the birds of Costa Rica'' by Stiles and Skutch
* ''Seabirds'' by Harrison,
External links
*
Field Guide on Flickr
(for Antigua, Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
, Nevis
Nevis is a small island in the Caribbean Sea that forms part of the inner arc of the Leeward Islands chain of the West Indies. Nevis and the neighbouring island of Saint Kitts constitute one country: the Federation of Saint Kitts and ...
, Nicaragua
Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the countr ...
, Uruguay
Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...
) with Range Map at bird-stamps.org
*
*
{{Authority control
black skimmer
Native birds of the Eastern United States
Birds of the Americas
black skimmer
black skimmer