Xantus's Murrelet
Encyclopedia
Xantus's Murrelet 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 colonies and by oil spills.
The species is named for the Hungarian
ornithologist John Xantus de Vesey who described it from specimens collected off Baja California
.
is a small black and white auk with a small head and thin sharp bill. It resembles the closely related Craveri's Murrelet
, with which it shares the distinction of being the most southerly living of all the auk species. It breeds on islands in the Channel Islands of California
, the largest colonies being on the Coronado Islands
http://www.ucsc.edu/news_events/text.asp?pid=1153 and on Santa Barbara Island
, and also several islands off Baja California, including Isla Guadalupe
. After the breeding season it disperses north at sea, usually to offshore waters, as far as British Columbia
.
Xantus's Murrelet feeds far out at sea, often in association with large pelagic predatory fish like tuna
, on larval fish like anchovies
, sardine
s and Sebastes
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
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 chicks are highly precocial
, 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. A female shot at Isla Guadalupe at the end of June was moult
ing its primary remiges (flight feathers) and unable to fly.
) have become rarer. The species is currently classified as Vulnerable (VU B2ab(iv,v); C2a(ii)) by the IUCN.
Xantus's Murrelet is mainly threatened by oil spill
s, as much of its population lives near the busy shipping lanes connecting Los Angeles
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
s and feral cat
s; this threat has been lessened lately by efforts to restore
its habitat by removing introduced predators. In one case the population of rats was removed from Anacapa Island
by the use of poisoned bait, the money for which being paid by a trust fund from an oil spill settlement.
Seabird
Seabirds are birds that have 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 environmental problems and feeding niches have resulted in similar adaptations...
found in the California Current
California Current
The California Current is a Pacific Ocean current that moves south along the western coast of North America, beginning off southern British Columbia, and ending off southern Baja California. There are five major coastal currents affiliated with upwelling zones...
system in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. This auk
Auk
An auk is a bird of the family Alcidae in the order Charadriiformes. Auks are superficially similar to penguins due to their black-and-white colours, their upright posture and some of their habits...
breeds on islands off California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It is threatened by predators introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
to its breeding colonies and by oil spills.
The species is named for the Hungarian
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
ornithologist John Xantus de Vesey who described it from specimens collected off Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
.
Description and range
This speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
is a small black and white auk with a small head and thin sharp bill. It resembles the closely related Craveri's Murrelet
Craveri's Murrelet
Craveri’s Murrelet 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 California in the USA, primarily during post-breeding dispersal...
, with which it shares the distinction of being the most southerly living of all the auk species. It breeds on islands in the Channel Islands of California
Channel Islands of California
The Channel Islands of California are a chain of eight islands located in the Pacific Ocean off the coast of Southern California along the Santa Barbara Channel in the United States of America...
, the largest colonies being on the Coronado Islands
Coronado Islands
The Coronado Islands are a group of four islands off the northwest coast of the Mexican state of Baja California. Battered by the wind and waves, they are largely infertile and uninhabited except for a small military detachment and a few lighthouse keepers...
http://www.ucsc.edu/news_events/text.asp?pid=1153 and on Santa Barbara Island
Santa Barbara Island
Santa Barbara Island is a small island of the Channel Islands archipelago in California. It is located about off the Southern California coast from the Palos Verdes Peninsula, near Los Angeles in Ventura County, California....
, and also several islands off Baja California, including Isla Guadalupe
Guadalupe Island
Guadalupe Island, or Isla Guadalupe is a volcanic island located 241 kilometers off the west coast of Mexico's Baja California peninsula and some 400 kilometers southwest of the city of Ensenada in Baja California state, in the Pacific Ocean...
. After the breeding season it disperses north at sea, usually to offshore waters, as far as British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
.
Behaviour
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...
, on larval fish like anchovies
Anchovy
Anchovies are a family of small, common salt-water forage fish. There are 144 species in 17 genera, found in the Atlantic, Indian, and Pacific Oceans. Anchovies are usually classified as an oily fish.-Description:...
, sardine
Sardine
Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....
s and Sebastes
Sebastes
Sebastes is a genus of fish in the family Sebastidae , most of which have the common name of rockfish. Most of the world's almost 110 Sebastes species live in the north Pacific, although two live in the south Pacific/Atlantic and four Sebastes is a genus of fish in the family Sebastidae (though...
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
Bird flight
Flight is the main mode of locomotion used by most of the world's bird species. Flight assists birds while feeding, breeding and avoiding predators....
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
Ancient Murrelet
The Ancient Murrelet, Synthliboramphus antiquus, is a bird in the auk family. It breeds from the Yellow Sea , through the Russian Pacific coast and the Aleutian Islands to the Haida Gwaii archipelago of British Columbia, where about half of the world population breeds.These birds breed in colonies,...
) the chicks are highly precocial
Precocial
In biology, the term precocial refers to species in which the young are relatively mature and mobile from the moment of birth or hatching. The opposite developmental strategy is called "altricial," where the young are born or hatched helpless. Extremely precocial species may be called...
, 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. A female shot at Isla Guadalupe at the end of June was moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
ing its primary remiges (flight feathers) and unable to fly.
Status and conservation
By the end of the 20th century, Xantus's Murrelet was considered to be among the most endangered species of auk.. This has changed since, but not because the present species' status has improved, but because other auks (e.g. Kittlitz's MurreletKittlitz's Murrelet
The Kittlitz's Murrelet, is a small alcid found in the waters off Alaska and Eastern Siberia. This critically endangered species is, like the closely related Marbled Murrelet, unusual for seabirds in not being colonial, nesting instead in isolated locations on mountain tops, where the nests were...
) have become rarer. The species is currently classified as Vulnerable (VU B2ab(iv,v); C2a(ii)) by the IUCN.
Xantus's Murrelet is mainly threatened by oil spill
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...
s, as much of its population lives near the busy shipping lanes connecting Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
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
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s and feral cat
Feral cat
A feral cat is a descendant of a domesticated cat that has returned to the wild. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats are born in the wild; the offspring of a stray cat can be considered feral if born in the wild.In many parts of...
s; this threat has been lessened lately by efforts to restore
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 important breeding grounds for seabirds and some...
its habitat by removing introduced predators. In one case the population of rats was removed from Anacapa Island
Anacapa Island
Anacapa Island is a small volcanic island located about off the coast of Port Hueneme, California, in Ventura County. The Island is composed of a series of narrow islets six miles long, running in a mostly east-west orientation, five miles east of Santa Cruz Island...
by the use of poisoned bait, the money for which being paid by a trust fund from an oil spill settlement.
External links
- Xantus Murrelet Photos
- BirdLife Species Factsheet.
- Photo montereyseabirds.com
- Photo; Article Channel Islands National Marine Sanctuary
- Xantus's Murrelet photo gallery VIREO
