The Guadalupe murrelet (''Synthliboramphus hypoleucus'') or Xantus' Murrelet is a small

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 ...

found in the

California Current The California Current is a cold water Pacific Ocean current that moves southward along the western coast of North America, beginning off southern British Columbia and ending off southern Baja California Sur. It is considered an Eastern boundary ...

system in the

Pacific Ocean 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 ...

. This

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 ...

breeds on islands off

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

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 ...

. It is threatened by predators introduced to its breeding

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'' ...

and by oil spills. This species together with the

Scripps's murrelet Scripps's murrelet (''Synthliboramphus scrippsi'') is a small seabird found in the California Current system in the Pacific Ocean. This auk breeds on islands off California and Mexico. It is threatened by predators introduced to its breeding col ...

were considered conspecific and were classified under ''S. hypoleucus''; known collectively as Xantus's murrelet until 2012. Enough evidence was collected to consider both species distinct based on a lack of evidence of interbreeding where the two species nest together on the San Benito Islands, differences in facial pattern and bill shape, vocalizations and genetics.

Description and range

This

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 ...

is a small black and white auk with a small head and thin sharp bill. It resembles the closely related Scripps's and

Craveri's murrelet Craveri's murrelet (''Synthliboramphus craveri'') is a small seabird which breeds on offshore islands in both the Pacific Ocean and the Gulf of California off the Baja peninsula of Mexico. It also wanders fairly regularly as far as central Calif ...

, with which it shares the distinction of being the most southerly living of all the auk species. It breeds from

Guadalupe Island Guadalupe Island ( es, Isla Guadalupe, link=no) is a volcanic island located off the western coast of Mexico's Baja California Peninsula and about southwest of the city of Ensenada in the state of Baja California, in the Pacific Ocean. The ...

south to the San Benito Islands. After the breeding season it disperses locally at sea northward up to southern California in the United States.

Behavior

Guadalupe murrelet feeds far out at sea, often in association with large

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 ...

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: ...

, on larval fish like

anchovies An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...

sardine "Sardine" and "pilchard" are common names for various species of small, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century, a folk etymology says it comes from the Ital ...

s and ''

Sebastes ''Sebastes'' is a genus of marine ray-finned fish belonging to the subfamily Sebastinae part of the family Scorpaenidae, most of which have the common name of rockfish. A few are called ocean perch, sea perch or redfish instead. They are found i ...

'' rockfish. Like all auks it is a wing-propelled diver, chasing down prey under the water with powerful wingbeats. There is some speculation that it may feed cooperatively in pairs, as it is almost always observed in pairs, even during the non-breeding season. It

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

well, and can take off without taxiing. It nests in small crevices, caves and under dense bushes on arid islands in loose scattered colonies. It returns to the colony only at night, laying two eggs which are incubated for about a month. Like other synthliboramphine murrelets (e.g. the

ancient murrelet The ancient murrelet (') is a bird in the auk family. The English term "murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot. Ancient murrelets are called "ancient" because th ...

) the chicks are highly

precocial In biology, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the mome ...

, leaving the nest within two days of hatching and running actively towards the sea, where the parents call to them. Once at sea the family swims to offshore waters. Little is known about the time at sea due to difficulties in studying them.

Status and conservation

By the end of the 20th century, the Xantus's murrelet complex was considered to be among the most endangered group of auk.

IUCN Redlist The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

(1988, 1994, 2000) This has changed since, but not because the present species' status has improved, but because other auks have become rarer. Guadalupe murrelet is mainly threatened by

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, as much of its population lives near the busy

shipping lane A sea lane, sea road or shipping lane is a regularly used navigable route for large water vessels (ships) on wide waterways such as oceans and large lakes, and is preferably safe, direct and economic. During the Age of Sail, they were determined b ...

s connecting

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

to other ports. Because a large part of its small population nests in such a small area a single catastrophic oil spill could have far reaching implications. It is also threatened by introduced species such as

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

s and

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; this threat has been lessened lately by efforts to restore its habitat by removing introduced predators.

Description and range

Behavior

Status and conservation

References

Further reading