Rhinoceros Auklet
Encyclopedia
The Rhinoceros Auklet is a seabird
and a close relative of the puffin
s. It is the only living species of the genus
Cerorhinca. Given its close relationship with the puffins, the common name Rhinoceros Puffin has been proposed for the species.
It ranges widely across the North Pacific, feeding on small fish
and nesting in seabird colonies
. Its name is derived from a horn-like extension of the beak. This horn is only present in breeding adults, and like the elaborate sheath on the bill of puffins is shed every year.
The Rhinoceros Auklet (also known as the Rhino Auklet, Horn-billed Puffin, or Unicorn Puffin), is a medium-sized auk
with a large, strong, orange/brown bill (with the 'horn' protruding from it). The plumage
is dark on top and paler below; breeding adults (both male and female) possess white plumes above the eyes and behind the bill. Males are slightly larger than females (about 10% in mass).
The Rhinoceros Auklet is a North Pacific auk that breeds from California
(the Channel Islands) to the Aleutian Islands in Alaska
in North America
; and Hokkaidō
and Honshū
, Japan
, as well as North Korea
and Sakhalin Island in Asia
. It winters both in offshore and inshore waters, exhibiting some migration
.
The Rhinoceros Auklet nests in burrows dug into the soil, or in natural caves and cavities between 1 and 5 m deep. It prefers nesting sites on slight inclines to aid take-off, as it is a poor flier. A single egg is incubated by both parents for 45 days. The semiprecocial chick is then fed each night with a bill full of fish (in the manner of puffins) for 50 days; this nocturnal behaviour is believed to be a response to predation and kleptoparasitism
by gull
s.
At sea, Rhinoceros Auklets feed on fish
, with some krill
and squid
taken also. They feed inshore during the breeding season in the midwater. To catch their prey, they dive as deeply as 57 meters (187 ft) for as long as 148 seconds.
. Although today only one species remains, it used to be much more diverse, both in number of species and in distribution. Fossils have been found as far south as Baja California
. The first record of the clade from the Atlantic Ocean was reported by Smith et al. (2007) and suggests that the biogeographic history of Cerorhinca is more complex than previously thought. Known prehistoric species are:
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...
and a close relative of the puffin
Puffin
Puffins are any of three small species of auk in the bird genus Fratercula with a brightly coloured beak during the breeding season. These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crevices among...
s. It is the only living species of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Cerorhinca. Given its close relationship with the puffins, the common name Rhinoceros Puffin has been proposed for the species.
It ranges widely across the North Pacific, feeding on small 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 nesting in seabird colonies
Bird colony
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in close proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony...
. Its name is derived from a horn-like extension of the beak. This horn is only present in breeding adults, and like the elaborate sheath on the bill of puffins is shed every year.
The Rhinoceros Auklet (also known as the Rhino Auklet, Horn-billed Puffin, or Unicorn Puffin), is a medium-sized 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...
with a large, strong, orange/brown bill (with the 'horn' protruding from it). The plumage
Plumage
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...
is dark on top and paler below; breeding adults (both male and female) possess white plumes above the eyes and behind the bill. Males are slightly larger than females (about 10% in mass).
The Rhinoceros Auklet is a North Pacific auk that breeds from 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...
(the Channel Islands) to the Aleutian Islands in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
; and Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
and Honshū
Honshu
is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, as well as North Korea
North Korea
The Democratic People’s Republic of Korea , , is a country in East Asia, occupying the northern half of the Korean Peninsula. Its capital and largest city is Pyongyang. The Korean Demilitarized Zone serves as the buffer zone between North Korea and South Korea...
and Sakhalin Island in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. It winters both in offshore and inshore waters, exhibiting some migration
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...
.
The Rhinoceros Auklet nests in burrows dug into the soil, or in natural caves and cavities between 1 and 5 m deep. It prefers nesting sites on slight inclines to aid take-off, as it is a poor flier. A single egg is incubated by both parents for 45 days. The semiprecocial chick is then fed each night with a bill full of fish (in the manner of puffins) for 50 days; this nocturnal behaviour is believed to be a response to predation and kleptoparasitism
Kleptoparasitism
Kleptoparasitism or cleptoparasitism is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food...
by gull
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...
s.
At sea, Rhinoceros Auklets feed on 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...
, with some krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
and 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...
taken also. They feed inshore during the breeding season in the midwater. To catch their prey, they dive as deeply as 57 meters (187 ft) for as long as 148 seconds.
Evolution and prehistoric species
The genus Cerorhinca evolved in the North Pacific, apparently in the mid-late MioceneMiocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
. Although today only one species remains, it used to be much more diverse, both in number of species and in distribution. Fossils have been found as far south as 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...
. The first record of the clade from the Atlantic Ocean was reported by Smith et al. (2007) and suggests that the biogeographic history of Cerorhinca is more complex than previously thought. Known prehistoric species are:
- Dubious Auklet, Cerorhinca dubia (Late Miocene of San Barbara County, USA)
- Cerorhinca minor (Late Miocene/Early Pliocene of Cedros Island, Mexico)
- Cerorhinca reai (San Diego Late Pliocene, SW USA)
- Cerorhinca sp. (Early Pliocene, SE USA)
External links
- Rhinoceros Auklet Images http://tsuru-bird.net/image.htm Copyright 2009 - Monte M. Taylor