Galápagos Shearwater
Encyclopedia
The Galápagos Shearwater, Puffinus subalaris is a small shearwater
. Until recently it was considered to be a subspecies of Audubon's Shearwater
, but it is actually one of two members of a very ancient lineage of the small Puffinus species, the other being, as indicated by mtDNA cytochrome b
sequence
data, the Christmas Shearwater
(Austin et al., 2004).
It is an endemic breeder of the Galápagos Islands
, and is largely sedentary, although individuals are commonly seen as far as the Oaxaca
n coast of Mexico
.
being white. It sometimes has a dark collar. Both sexes are alike, as are the young after fledging
.
It is a slender-bodied shearwater, about 29–31 cm long, with a wingspan of around 63 cm and weighs 123-225 g. The species closely resembles the Tropical Shearwater, although the latter is typically blacker and has a longer tail.
. It flies low over the water and feeds on squid
, fish
and offal. It intersperses 4-10 stiff wing beats with shallow glides.
Shearwater
Shearwaters are medium-sized long-winged seabirds. There are more than 30 species of shearwaters, a few larger ones in the genus Calonectris and many smaller species in the genus Puffinus...
. Until recently it was considered to be a subspecies of Audubon's Shearwater
Audubon's Shearwater
Audubon's Shearwater, Puffinus lherminieri, is a common tropical seabird from the family Procellariidae. Sometimes called Dusky-backed Shearwater, the scientific name of this species commemorates the French naturalist Félix Louis L'Herminier....
, but it is actually one of two members of a very ancient lineage of the small Puffinus species, the other being, as indicated by mtDNA cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data, the Christmas Shearwater
Christmas Shearwater
The Christmas Shearwater, Puffinus nativitatis, is a medium-sized shearwater of the tropical Central Pacific. It is a poorly known species due to its remote nesting habits, and it has not been extensively studied at sea either....
(Austin et al., 2004).
It is an endemic breeder of the Galápagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
, and is largely sedentary, although individuals are commonly seen as far as the Oaxaca
Oaxaca
Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
n coast of 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...
.
Description
The Galápagos Shearwater has dark brown upperparts, undertail and underwing flight feathers, the rest of the underparts plumagePlumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
being white. It sometimes has a dark collar. Both sexes are alike, as are the young after fledging
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
.
It is a slender-bodied shearwater, about 29–31 cm long, with a wingspan of around 63 cm and weighs 123-225 g. The species closely resembles the Tropical Shearwater, although the latter is typically blacker and has a longer tail.
Behaviour
The Galápagos Shearwater is a gregarious species and will feed at sea with other shearwaters and boobiesBooby
A booby is a seabird in the genus Sula, part of the Sulidae family. Boobies are closely related to the gannets , which were formerly included in Sula.-Description:...
. It flies low over the water and feeds on squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
, 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...
and offal. It intersperses 4-10 stiff wing beats with shallow glides.