Synthliboramphus
Encyclopedia
Synthliboramphus is a small genus of seabird
s in the auk
family from the North Pacific. It consists of four species:
The first two species were formally considered conspecific, and are sometimes separated in the genus Endomychura.
Fossil
remains of two prehistoric species are known: an undescribed Synthliboramphus sp. from the Late Miocene or Early Pliocene (c. 5 mya) of Cedros Island
, Mexico
, and Synthliboramphus rineyi from the Late Pliocene (around 3.5-2 mya) San Diego Formation
of the southwestern USA.
These birds breed in colonies, their eggs being laid directly amongst tree roots or in rock crevices. They are nocturnal on the breeding grounds, presumably to reduce predation, and for the same reason the precocial
young are never fed at the nest, being taken to sea a couple of days after hatching. The parents call to the young from out at sea, and the chicks swim towards the adults who keep moving further out throughout the night.
Synthliboramphus species disperse out to sea after breeding, with northern species migrating
further south.
Synthliboramphus auks are small, with mainly black upper parts and white the short wings. These birds forage for food like other auks, by swimming underwater. They mainly eat fish
, also some crustacean
s and other small invertebrate
s.
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...
s in the 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...
family from the North Pacific. It consists of four species:
- Xantus's MurreletXantus's MurreletXantus'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...
, Synthliboramphus hypoleucus - Craveri's MurreletCraveri's MurreletCraveri’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...
, Synthliboramphus craveri - Ancient MurreletAncient MurreletThe 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,...
, Synthliboramphus antiquus - Japanese MurreletJapanese MurreletThe Japanese Murrelet, Synthliboramphus wumizusume also known as Crested Murrelet is a small bird that inhabits rocky islets and reefs in the warm waters of Japan, Russia and South Korea...
, Synthliboramphus wumizusume
The first two species were formally considered conspecific, and are sometimes separated in the genus Endomychura.
Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains of two prehistoric species are known: an undescribed Synthliboramphus sp. from the Late Miocene or Early Pliocene (c. 5 mya) of Cedros Island
Cedros Island
Cedros Island is a Mexican island in the Pacific Ocean....
, 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...
, and Synthliboramphus rineyi from the Late Pliocene (around 3.5-2 mya) San Diego Formation
San Diego Formation
The San Diego Formation is a mostly sand, with rock layer from a former bay of San Diego of Late Pliocene age.Besides those of clams and other mollusks, quite a few bird fossils have been found in this geological formation. Among them is a possible ancestor of Cassin's Auklet and the loons Gavia...
of the southwestern USA.
These birds breed in colonies, their eggs being laid directly amongst tree roots or in rock crevices. They are nocturnal on the breeding grounds, presumably to reduce predation, and for the same reason the 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...
young are never fed at the nest, being taken to sea a couple of days after hatching. The parents call to the young from out at sea, and the chicks swim towards the adults who keep moving further out throughout the night.
Synthliboramphus species disperse out to sea after breeding, with northern species migrating
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
further south.
Synthliboramphus auks are small, with mainly black upper parts and white the short wings. These birds forage for food like other auks, by swimming underwater. They mainly eat fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, also some crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and other small invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s.