Yellow-billed Loon
Encyclopedia
The Yellow-billed Loon (Gavia adamsii), also known as the White-billed Diver, is the largest member of the loon
or diver family. Breeding adults have a black head, white underparts and chequered black-and-white mantle. Non-breeding plumage
is drabber with the chin and foreneck white. The main distinguishing feature from Great Northern Loon is the longer straw-yellow bill which, because the culmen is straight, appears slightly uptilted.
It breeds in the Arctic
and winters mainly at sea along the coast
s of the northern Pacific Ocean
and northwestern Norway
; it also sometimes overwinters on large inland lakes. It occasionally strays well south of its normal wintering range, and has been recorded as a vagrant in more than 22 countries. This species
, like all divers, is a specialist fish
-eater, catching its prey underwater. Its call is an eerie wailing, lower pitched than Great Northern Diver.
in 1859 based on a specimen collected in Alaska, the Yellow-billed Loon is a monotypic species, with no subspecies despite its large Holarctic
range. It is closely related to the Great Northern Loon, which it strongly resembles in plumage and behaviour; some taxonomists consider the two species to be allopatric forms of the same superspecies
. Both are thought to have evolved from a population of Black-throated Loons which colonized the Nearctic
and were subsequently cut off from other populations.
The genus name Gavia comes from the Latin
for "sea mew", as used by ancient Roman naturalist Pliny the Elder
. The specific epithet adamsii honours Edward Adams, a British Naval surgeon and naturalist who sketched and collected numerous species, including this one, on several trips to the Arctic
. The word "loon" is thought to have derived from the Swedish lom, the Old Norse or Icelandic lómr, or the Old Dutch loen, all of which mean "lame" or "clumsy", and is a probable reference to the difficulty that all loons have in moving about on land. "Diver" refers to the family's underwater method of hunting for prey, while "yellow-billed" and "white-billed" are references to the bird's distinctively pale bill
.
, with a purple gloss on its head and neck.
and the northwestern coast of Norway
. It has been recorded as a breeding bird in Russia
, Canada and the United States. Though it winters primarily to the north of 50° N, its winter range extends south to 35° N off the coast of Japan, and it has been recorded as a vagrant in more than 20 countries, including some as far south as Mexico
and Spain
.
of plant material very close to the edge of the water. The female lays two eggs
.
s, molluscs and annelid
s. It dives in pursuit of prey, which is caught underwater.
to Near Threatened
, as the species appears to be in a "moderately rapid" population decline. An unsustainable level of subsistence harvesting by indigenous peoples was specifically named as the main threat.
The Yellow-billed Loon is one of the species
to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies; in the Americas
, it is protected by the Migratory Bird Treaty Act of 1918
.
Loon
The loons or divers are a group of aquatic birds found in many parts of North America and northern Eurasia...
or diver family. Breeding adults have a black head, white underparts and chequered black-and-white mantle. Non-breeding plumage
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
is drabber with the chin and foreneck white. The main distinguishing feature from Great Northern Loon is the longer straw-yellow bill which, because the culmen is straight, appears slightly uptilted.
It breeds in the Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
and winters mainly at sea along the coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
s of the northern 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...
and northwestern Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
; it also sometimes overwinters on large inland lakes. It occasionally strays well south of its normal wintering range, and has been recorded as a vagrant in more than 22 countries. This species
Species
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...
, like all divers, is a specialist 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...
-eater, catching its prey underwater. Its call is an eerie wailing, lower pitched than Great Northern Diver.
Taxonomy and etymology
First described by English zoologist George Robert GrayGeorge Robert Gray
George Robert Gray FRS was an English zoologist and author, and head of the ornithological section of the British Museum, now the Natural History Museum, in London for forty-one years...
in 1859 based on a specimen collected in Alaska, the Yellow-billed Loon is a monotypic species, with no subspecies despite its large Holarctic
Holarctic
The Holarctic ecozone refers to the habitats found throughout the northern continents of the world as a whole. This region is divided into the Palearctic, consisting of Northern Africa and all of Eurasia, with the exception of Southeast Asia and the Indian subcontinent, and the Nearctic,...
range. It is closely related to the Great Northern Loon, which it strongly resembles in plumage and behaviour; some taxonomists consider the two species to be allopatric forms of the same superspecies
Superspecies
A superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all species complexes, whether cryptices or ring species are superspecies, and vice versa, but many are...
. Both are thought to have evolved from a population of Black-throated Loons which colonized the Nearctic
Nearctic
The Nearctic is one of the eight terrestrial ecozones dividing the Earth's land surface.The Nearctic ecozone covers most of North America, including Greenland and the highlands of Mexico...
and were subsequently cut off from other populations.
The genus name Gavia comes from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "sea mew", as used by ancient Roman naturalist Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
. The specific epithet adamsii honours Edward Adams, a British Naval surgeon and naturalist who sketched and collected numerous species, including this one, on several trips to the Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
. The word "loon" is thought to have derived from the Swedish lom, the Old Norse or Icelandic lómr, or the Old Dutch loen, all of which mean "lame" or "clumsy", and is a probable reference to the difficulty that all loons have in moving about on land. "Diver" refers to the family's underwater method of hunting for prey, while "yellow-billed" and "white-billed" are references to the bird's distinctively pale bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
.
Description
With a length of 76 to 97 cm (29.9 to 38.2 in), a wingspan of 135 to 160 cm (53.1 to 63 in), and a weight ranging from 4 to 6.4 kg (8.8 to 14.1 lb), the Yellow-billed Loon is the largest member of the loon (diver) family. The adult is primarily black and white in breeding 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...
, with a purple gloss on its head and neck.
Habitat and range
The Yellow-billed Loon is an Arctic species, breeding primarily along the coasts of the Arctic Ocean as far north as 78° N and wintering on sheltered coastal waters of the northern Pacific OceanPacific 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...
and the northwestern coast of Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
. It has been recorded as a breeding bird in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, Canada and the United States. Though it winters primarily to the north of 50° N, its winter range extends south to 35° N off the coast of Japan, and it has been recorded as a vagrant in more than 20 countries, including some as far south as 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 Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
.
Breeding
Though it prefers freshwater pools or lakes in the tundra, the Yellow-billed Loon will also breed along rivers, estuaries or the coast in low-lying areas of the Arctic; in general, it avoids forested areas. Breeding typically starts in early June, though it is dependent on the timing of the spring thaw. Like all members of its family, the Yellow-billed Loon builds a nestBird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
of plant material very close to the edge of the water. The female lays two eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
.
Feeding
The Yellow-billed Loon is a specialist fish eater, though it also takes crustaceanCrustacean
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, molluscs and annelid
Annelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...
s. It dives in pursuit of prey, which is caught underwater.
Conservation and threats
In 2010, the IUCN (International Union for the Conservation of Nature) changed the status of the Yellow-billed Loon from Least ConcernLeast Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
to Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
, as the species appears to be in a "moderately rapid" population decline. An unsustainable level of subsistence harvesting by indigenous peoples was specifically named as the main threat.
The Yellow-billed Loon is one of the species
Species
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...
to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies; in the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
, it is protected by the Migratory Bird Treaty Act of 1918
Migratory Bird Treaty Act of 1918
The Migratory Bird Treaty Act of 1918 , codified at , is a United States federal law, at first enacted in 1916 in order to implement the convention for the protection of migratory birds between the United States and Great Britain...
.
External links
- Gerrit Vyn Photography Photographs
- VIREO Photographs
- IBC Video on the Internet Bird Collection
- Flicker Field Guide Birds of the World Photographs