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Auklet
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'' (auk), from Proto-Germanic *''alkǭ'' (sea-bird, auk). The family contains 25 extant or recently extinct species that are divided into 11 genera. Apart from the extinct great auk, all auks can fly, and are excellent swimmers (appearing to "fly") and divers, but their walking appears clumsy. Several species have different English names in Europe and North America. The two species known as murres in North America are called guillemots in Europe, and the species called little auk in Europe is referred to as dovekie in North America. Description Auks are superficially similar to penguins, having black-and-white colours, upright posture, and some of their habits. Nevertheless, they are not closely related to penguins, but rather are believed to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aethia
''Aethia'' is a genus of four small (85–300g) auklets endemic to the North Pacific Ocean, Bering Sea and Sea of Okhotsk and among some of North America's most abundant seabirds. The relationships between the four true auklets remains unclear. Auklets are threatened by invasive species such as Arctic foxes (''Alopex lagopus'') and Norway rats (''Rattus norvegicus'') because of their high degree of coloniality and crevice-nesting. Taxonomy and evolution The genus ''Aethia'' occurs only in the North Pacific and adjacent waters, mainly in the Bering Sea region. Along with Cassin's auklet (''Ptychoramphus aleuticus'') they comprise the monophyletic tribe Aethinii. Molecular work has not yet resolved the relationship between the ''Aethia'' auklets, but the group is a sister group to Cassin's auklet, which is, in turn, a sister group to the Fraterculine auks (puffins and rhinoceros auklet). The genus ''Aethia'' did not enter into widespread use until the 1960s. Initially, the aukl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parakeet Auklet
The parakeet auklet (''Aethia psittacula'') is a small seabird of the North Pacific. Parakeet Auklets used to be placed on its own in the genus ''Cyclorrhynchus'' ( Kaup, 1829) but recent morphological and genetic evidence suggest it should be placed in the genus ''Aethia'', making them closely related to crested auklets and least auklets. It is associated with the boreal waters of Alaska, Kamchatka and Siberia. It breeds on the cliffs, slopes and boulder fields of offshore islands, generally moving south during the winter. Description The parakeet auklet is a small (23 cm) auk with a short orange bill that is upturned to give the bird its curious fixed expression. The upward bend of the beak has been observed to provide advantages in picking up small food pieces from the sea bottom as well as in assisting in the disintegration of larger food objects. The bird's plumage is dark above and white below. with a single white plume projecting back from the eye. There is a small a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcinae
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'' (auk), from Proto-Germanic *''alkǭ'' (sea-bird, auk). The family contains 25 extant or recently extinct species that are divided into 11 genera. Apart from the extinct great auk, all auks can fly, and are excellent swimmers (appearing to "fly") and divers, but their walking appears clumsy. Several species have different English names in Europe and North America. The two species known as murres in North America are called guillemots in Europe, and the species called little auk in Europe is referred to as dovekie in North America. Description Auks are superficially similar to penguins, having black-and-white colours, upright posture, and some of their habits. Nevertheless, they are not closely related to penguins, but rather are believed to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraterculinae
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'' (auk), from Proto-Germanic *''alkǭ'' (sea-bird, auk). The family contains 25 extant or recently extinct species that are divided into 11 genera. Apart from the extinct great auk, all auks can fly, and are excellent swimmers (appearing to "fly") and divers, but their walking appears clumsy. Several species have different English names in Europe and North America. The two species known as murres in North America are called guillemots in Europe, and the species called little auk in Europe is referred to as dovekie in North America. Description Auks are superficially similar to penguins, having black-and-white colours, upright posture, and some of their habits. Nevertheless, they are not closely related to penguins, but rather are believed to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Auklet
The least auklet (''Aethia pusilla'') is a seabird and the smallest species of auk. It is the most abundant seabird in North America, and one of the most abundant in the world, with a population of around nine million birds. They breed on the islands of Alaska and Siberia, and spend the winter close to the edge of the ice sheet. Their largest colonies are on the Aleutian Islands, St. Lawrence Island and Little Diomede Island. Diet and feeding Least auklets feed predominantly on calanoid copepods, particularly those of the genus '' Neocalanus''. They also eat euphausiids, pteropods and other zooplankton species. They hunt for these in stratified waters caused where upwelling and thermoclines cause these prey items to be tightly clumped together. Like all auks they are pursuit divers, using their wings to provide thrust and "fly" under the water. They are voracious predators, consuming 86% of their body weight each day. Breeding Least auklets are highly colonial, nesting in rocky ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Razorbill
The razorbill, razor-billed auk, or lesser auk (''Alca torda'') is a colonial seabird and the only extant member of the genus '' Alca'' of the family Alcidae, the auks. It is the closest living relative of the extinct great auk (''Pinguinis impennis''). Wild populations live in the subarctic waters of the Atlantic Ocean. Razorbills are primarily black with a white underside. The male and female are identical in plumage; however, males are generally larger than females. This agile bird, which is capable of both flight and diving, has a predominantly aquatic lifestyle and only comes to land in order to breed. It is monogamous, choosing one partner for life. Females lay one egg per year. Razorbills nest along coastal cliffs in enclosed or slightly exposed crevices. The parents spend equal amounts of time incubating, and once the chick has hatched, they take turns foraging for their young. In 1918, the razorbill was protected in the United States by the Migratory Bird Treaty Act. Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thick-billed Murre
The thick-billed murre or Brünnich's guillemot (''Uria lomvia'') is a bird in the auk family (Alcidae). This bird is named after the Danish zoologist Morten Thrane Brünnich. The very deeply black North Pacific subspecies ''Uria lomvia arra'' is also called Pallas' murre after its describer. The genus name is from Ancient Greek ''ouria'', a waterbird mentioned by Athenaeus. The species term ''lomvia'' is a Swedish word for an auk or diver. The English "guillemot" is from French ''guillemot'' probably derived from ''Guillaume'', "William". "Murre" is of uncertain origins, but may imitate the call of the common guillemot. Murres have the highest flight cost, for their body size, of any animal. Description Since the extinction of the great auk in the mid-19th century, the murres are the largest living members of the Alcidae.Nettleship (1996) The thick-billed murre and the closely related common guillemot (or common murre, ''U. aalge'') are similarly sized, but the thick-billed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cormorant
Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven genera. The great cormorant (''Phalacrocorax carbo'') and the common shag (''Gulosus aristotelis'') are the only two species of the family commonly encountered in Britain and Ireland and "cormorant" and "shag" appellations have been later assigned to different species in the family somewhat haphazardly. Cormorants and shags are medium-to-large birds, with body weight in the range of and wing span of . The majority of species have dark feathers. The bill is long, thin and hooked. Their feet have webbing between all four toes. All species are fish-eaters, catching the prey by diving from the surface. They are excellent divers, and under water they propel themselves with their feet with help from their wings; some cormorant species have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift. Lifting structures used in water include various foils, such as hydrofoils. Hydrodynamics is the governing science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines. Etymology and usage For many centuries, the word "wing", from the Old Norse ''vængr'', referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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