The black-necked grebe or eared grebe (''Podiceps nigricollis'') is a member of the
grebe
Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably ...
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of water birds. It was described in 1831 by
Christian Ludwig Brehm
Christian Ludwig Brehm (24 January 1787 – 23 June 1864) was a German pastor and ornithologist. He was the father of the zoologist Alfred Brehm.
Life
Brehm was born in Schönau near Gotha on 24 January 1787. He was educated at Universit ...
. There are currently three accepted subspecies, including the
nominate subspecies. Its breeding plumage features a distinctive ochre-coloured plumage which extends behind its eye and over its ear coverts. The rest of the upper parts, including the head, neck, and breast, are coloured black to blackish brown. The flanks are tawny rufous to maroon-chestnut, and the abdomen is white. When in its non-breeding plumage, this bird has greyish-black upper parts, including the top of the head and a vertical stripe on the back of the neck. The flanks are also greyish-black. The rest of the body is a white or whitish colour. The juvenile has more brown in its darker areas. The subspecies ''californicus'' can be distinguished from the nominate by the former's usually longer bill. The other subspecies, ''P. n. gurneyi'', can be differentiated by its greyer head and upper parts and by its smaller size. ''P. n. gurneyi'' can also be told apart by its lack of a non-breeding plumage. This species is present in parts of
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
,
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
, and the
Americas
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World.
Along with th ...
.
The black-necked grebe uses multiple foraging techniques. Insects, which make up the majority of this bird's diet, are caught either on the surface of the water or when they are in flight. It occasionally practices
foliage gleaning. This grebe dives to catch
crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s,
molluscs, tadpoles, and small frogs and fish. When
moult
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
ing at saline lakes, this bird feeds mostly on
brine shrimp
''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp. It is the only genus in the family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to the first half of the 10th century AD from Urmia L ...
. The black-necked grebe makes a floating cup nest on an open lake. The nest cup is covered with a disc. This nest is located both in colonies and by itself. During the breeding season, which varies depending on location, this species will lay one (sometimes two)
clutch of three to four eggs. The number of eggs is sometimes larger due to conspecific
brood parasitism
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its ow ...
. After a 21-day incubation period, the eggs hatch, and then the nest is deserted. After about 10 days, the parents split up the chicks between themselves. After this, the chicks become independent in about 10 days, and fledge in about three weeks.
Although it generally avoids flight, the black-necked grebe travels as far as during
migration
Migration, migratory, or migrate may refer to: Human migration
* Human migration, physical movement by humans from one region to another
** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
. In addition, it becomes flightless for two months after completing a migration to reach an area where it can safely moult. During this moult, the grebe can double in weight. The migrations to reach these areas are dangerous, sometimes with thousands of grebe deaths. In spite of this, it is classified as a
least concern species
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
by the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...
(IUCN). It is likely that this is the most numerous grebe in the world. There are potential threats to it, such as oil spills, but these are not likely to present a major risk to the overall population.
Taxonomy
This species was first described by
Carl Ludwig Hablitz
Carl Ludwig von Hablitz (2 April 1752 – 9 October 1821), also known as Karl Ivanovich Gablits (russian: Карл Ива́нович Га́блиц), was a Prussian-born Russian botanist.
Biography
Hablitz was born in Königsberg, in 1758 his f ...
in 1783 as ''Colymbus caspicus'', from a bird in
Bandar-e Anzali
Bandar-e Anzali ( fa, بندرانزلی, also Romanized as Bandar-e Anzalī; renamed as Bandar-e Pahlavi during the Pahlavi dynasty) is a city of Gilan Province, Iran. At the 2011 census, its population was 144,664.
Anzali is one of the mos ...
. This was originally thought to be a synonym for the
horned grebe
The horned grebe or Slavonian grebe (''Podiceps auritus'') is a relatively small waterbird in the family Podicipedidae. There are two known subspecies: ''P. a. auritus'', which breeds in the Palearctic, and ''P. a. cornutus'', which breeds in ...
, until
Erwin Stresemann
Erwin Friedrich Theodor Stresemann (22 November 1889, in Dresden – 20 November 1972, in East Berlin) was a German naturalist and ornithologist. Stresemann was an ornithologist of extensive breadth who compiled one of the first and most compr ...
discovered that the description applied more to the black-necked grebe in 1948. Before this, the earliest description was thought to be by
Christian Ludwig Brehm
Christian Ludwig Brehm (24 January 1787 – 23 June 1864) was a German pastor and ornithologist. He was the father of the zoologist Alfred Brehm.
Life
Brehm was born in Schönau near Gotha on 24 January 1787. He was educated at Universit ...
in 1831, who gave this bird its current scientific name of ''Podiceps nigricollis''
from a German bird. To resolve this, the
International Commission on Zoological Nomenclature suppressed the name ''C. caspicus''.
The genus name ''Dytes'' is sometimes used for this species,
a placement which was formalized by
Robert Ridgway
Robert Ridgway (July 2, 1850 – March 25, 1929) was an American ornithologist specializing in systematics. He was appointed in 1880 by Spencer Fullerton Baird, secretary of the Smithsonian Institution, to be the first full-time curator of bi ...
in 1881.
This bird is closely related to the
silvery grebe
The silvery grebe (''Podiceps occipitalis'') is a species of grebe in the family Podicipedidae. It is found in the western and southern part of South America at altitudes of up to . Its natural habitat is freshwater lakes but it also feeds in sa ...
and the
Junin grebe. The extinct
Colombian grebe
The Colombian grebe (''Podiceps andinus''), was a grebe found in the Bogotá wetlands on the Bogotá savanna in the Eastern Ranges of the Andes of Colombia. The species was still abundant in Lake Tota in 1945. The species has occasionally bee ...
is sometimes considered to be a subspecies of this species, in addition to three other extant subspecies:
* ''P. n. nigricollis'' –
( Brehm, CL, 1831):
nominate
Nomination is part of the process of selecting a candidate for either election to a public office, or the bestowing of an honor or award. A collection of nominees narrowed from the full list of candidates is a short list.
Political office
In the ...
, is found from western
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
to western
temperate Asia (wintering to the south and west), in central and eastern
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
, and in eastern Africa
* ''P. n. gurneyi'' –
(Roberts, 1919): is found in southern Africa
* ''P. n. californicus'' –
(Heermann, 1854): is found from southwestern Canada through the western U.S. It winters as far south as Guatemala
The generic name, ''Podiceps'', comes from two Latin words: ''podicis'', meaning "vent" or "anus" and ''pes'' meaning "foot". This is a reference to the attachment point of the bird's legs—at the extreme back end of its body. The specific epithet ''nigricollis'' is Latin for "black-necked": ''niger'' means "black" and ''collis'' means "neck".
The subspecies epithet ''californicus'' comes from "California", while ''gurneyi'' comes from the name of British
ornithologist John Henry Gurney Sr.
"Black-necked grebe" has been designated the official name by the
International Ornithological Committee
The International Ornithologists' Union, formerly known as the International Ornithological Committee, is a group of about 200 international ornithologists, and is responsible for the International Ornithological Congress and other international ...
(IOC).
Both common names for this species refer to features visible when the bird is in its breeding plumage; in such plumage, it has an all-black neck and a spray of golden plumes on each side of its head. The name "eared grebe" is nearly a century older than the name "black-necked grebe". The latter was first used in 1912 by Ernst Hartert, in an effort to bring the common name of the species in line with its scientific name. The name "eared grebe" is still used in North America to refer to this bird.
Description
![Eared Grebe](https://upload.wikimedia.org/wikipedia/commons/b/b9/Eared_Grebe.jpg)
The black-necked grebe usually measures between in length and weighs . The bird has a wingspan range of 20.5-21.6 in (52-55 cm).
The
nominate subspecies in breeding plumage has the head, neck, breast, and upper parts coloured black to blackish brown, with the exception of the
ochre-coloured fan of feathers extending behind the eye over the eye-coverts and sides of the nape. This eye is mostly red, with a narrow and paler yellow ring on the inner parts of the eye and an orange-yellow to pinkish-red .
The thin, upturned bill,
on the other hand, is black, and is connected to the eye by a blackish line starting at the . Sometimes, the foreneck can be found to be mostly tinged brown. The is blackish to drab brown in colour and has a white patch formed by the secondaries and part of the inner primaries. The flanks are coloured tawny rufous to maroon-chestnut and have the occasional blackish fleck. The and abdomen is white, with an exception to the former being the dark tertials and the mostly pale grey-brown outer primaries. The legs are a dark greenish grey. The sexes are similar.
In non-breeding plumage, the nominate has greyish-black upper parts, cap, nape, and hindneck, with the colour on the upper portion of the latter being contained in a vertical stripe. The dark colour of the cap reaches below the eye and can be seen, diffused, to the ear-coverts. Behind the ear-coverts on the sides of the neck, there are white ovals. The rest of the neck is grey to brownish-grey in colour and has white that varies in amount. The breast is white, and the abdomen is whitish. The flanks are coloured in a mix of blackish-grey with white flecks. The colour of the bill when not breeding differs from that of the breeding plumage, with the former being significantly more grey.
![Podiceps nigricollis IMG 4467](https://upload.wikimedia.org/wikipedia/commons/2/2b/Podiceps_nigricollis_IMG_4467.jpg)
The juvenile black-necked grebe is similar to the non-breeding adult. There are differences, however, including the fact that the dark areas are usually more brownish in the juvenile, with less black. The are often tinged pale grey, with whitish marks behind the eye. On the sides of the head and upper neck, there is a buffy or tawny tinge. The chick is downy and has a blackish-grey head with stripes and spots that are white or pale buff-grey. The throat and foreneck are largely pale. The upper parts are mostly dark grey in colour, and the abdomen is white.
The subspecies ''californicus'' usually has a longer bill compared to the nominate, and has brown-grey inner primaries during the breeding season. When not breeding, the nominate has diffuse and pale lores less often than ''Podiceps nigricollis californicus''. The other subspecies, ''P. n. gurneyi'', is the smallest of the three subspecies, in addition to having a greyer head and upper parts. The adult of this subspecies also has a rufous-brown tinge on its lesser wing-coverts. It also lacks a non-breeding plumage, in addition to the tufts on the side of its head being paler.
Vocalizations
When breeding, the black-necked grebe gives a quiet "ooeek" that ascends in pitch from an already high pitch. This call is also used as a territorial call, in addition to a low and fast trill, which itself is also used during courtship. Another call is a short "puuii" or "wit". This grebe is silent when it is not the breeding season
and when it is feeding or resting.
Distribution and habitat
This species breeds in vegetated areas of freshwater
lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s across Europe,
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
, Africa, northern
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
and the
southwest
The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each sepa ...
and
western
Western may refer to:
Places
*Western, Nebraska, a village in the US
*Western, New York, a town in the US
*Western Creek, Tasmania, a locality in Australia
*Western Junction, Tasmania, a locality in Australia
*Western world, countries that id ...
United States.
After breeding, this bird
migrates to saline lakes to moult.
Then, after completing the moult and waiting for sometimes several months,
it migrates to winter in places such as the south-western
Palearctic and the eastern parts of both Africa and Asia. It also winters in southern Africa, another place where it breeds. In the
Americas
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World.
Along with th ...
, it winters as far south as
Guatemala,
although the wintering population there is mainly restricted to islands in the
Gulf of California
The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja C ...
, the
Salton Sea
The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf ...
, and
Baja California
Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
.
When not breeding, its habitat is primarily saline lakes and coastal
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...
.
Behaviour
This grebe is highly
gregarious
Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies.
Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...
, usually forming large colonies when breeding and large flocks when not.
Breeding
This species builds its floating nest in the usually shallow water of open lakes.
The nest itself is anchored to the lake by plants.
It is built by both the male and the female and made out of plant matter.
Most of it is submerged, with the bottom of the shallow cup usually being level with the water. Above the cup, there is a flat disc.
This grebe nests both in colonies
and by itself. When it does not nest by itself, it will often nest in mixed-species colonies made up of
black-headed gull
The black-headed gull (''Chroicocephalus ridibundus'') is a small gull that breeds in much of the Palearctic including Europe and also in coastal eastern Canada. Most of the population is migratory and winters further south, but some birds r ...
s,
duck
Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form ...
s, and various other
waterbird
A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...
s.
The space between the nests in these colonies is often .
Whether it nests in colonies or not has an effect on the dimensions of the nest. When the bird is not in a colony, the nest has an average diameter of , although this can vary, with nests ranging from about to over . This is compared to nests in colonies, which have an average diameter of about .
It is suggested that rarely some pairs of this grebe will steward over multiple nests when in colonies.
![Eared Grebe Courting Display (34617077235)](https://upload.wikimedia.org/wikipedia/commons/5/53/Eared_Grebe_Courting_Display_%2834617077235%29.jpg)
Pair formation in the black-necked grebe usually starts during pauses in the migration to the breeding grounds, although it occasionally occurs before, in wintering pairs. This pair formation continues after this grebe has arrived to its breeding grounds.
Courtship occurs when it arrives at the breeding lake. The displays are performed in the middle of the lake. There is no territory involved in courting; individuals used the whole area of the lake. When advertising for a mate, a black-necked grebe will approach other black-necked grebes with its body fluffed out and its neck erect. It closes its beak to perform a call, ''poo-eee-chk'', with the last note only barely audible. Courtship generally stops at the start of nesting.
In the Northern Hemisphere, this bird breeds from April to August. In east Africa, the breeding season is at least from January to February, while in southern Africa, the breeding season is from October to April.
The black-necked grebe is
socially monogamous.
Conspecific or intraspecific
brood parasitism
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its ow ...
, where the female lays eggs in the nest of others of their own species is common with nearly 40% of nests being parasitized on average.
In terms of territory, this grebe will defend only its nest site.
![Podiceps nigricollis MWNH 1923](https://upload.wikimedia.org/wikipedia/commons/d/d1/Podiceps_nigricollis_MWNH_1923.JPG)
This grebe lays a
clutch, and sometimes two clutches,
of three to four chalky greenish or bluish eggs.
Nests that have been parasitized, however, will have two more eggs on average, even though the number the host lays is about the same no matter if it has been parasitized or not.
The eggs, although initially immaculate, do get stained by plant matter that the nest is built out of. The eggs measure on average and are incubated by both parents for about 21 days.
The laying date of the eggs is somewhat synchronized, with birds in small colonies having the laying dates spread out by just a few days, compared to large colonies, where the laying date is spread out over more than 10 days.
After the chicks hatch, the birds will desert their nest.
Even though the young can swim and dive during this time, they rarely do, instead staying on the parents' backs for four days after hatching.
This behaviour is present in all grebes, and is likely to have evolved because it reduces travel costs, specifically those back to the nest to brood the chicks and give them food.
After about 10 days, the parents split the chicks up, with each parent taking care of about half of the brood.
After this split, the chicks are independent in about 10 days,
and fledge in about three weeks.
When disturbed while incubating, this bird usually (just under 50% of the time) partly covers its eggs with nest material when the disruption is not sudden, but a bird with an incomplete clutch usually does not attempt to cover the eggs. When the disruption is sudden, on the other hand, the black-necked grebe usually (just under 50% of the time) does not cover its eggs. In comparison, other species of grebes cover up their eggs when leaving the nest.
Predation is usually not the primary cause of egg loss, with most nesting failures occurring after the chicks have hatched. A major cause of this is the chilling of the young.
Feeding
The black-necked grebe forages mainly by diving
from the water,
with dives usually lasting less than 30 seconds.
These dives are usually shorter in time when in more shallow water.
In between dives, this grebe rests for an average of 15 seconds.
When feeding on
brine shrimp
''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp. It is the only genus in the family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to the first half of the 10th century AD from Urmia L ...
at hypersaline lakes, it likely uses its large tongue to block the oral cavity. It is hypothesized that it then crushes prey against its palate to remove excess water.
It also forages by
gleaning
Gleaning is the act of collecting leftover crops from farmers' fields after they have been commercially harvested or on fields where it is not economically profitable to harvest. It is a practice described in the Hebrew Bible that became a legall ...
foliage, plucking objects off of the surface of water, having its head submerged while swimming, and sometimes capturing flying insects.
This grebe eats mostly insects, of both adult and
larval stages, as well as
crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s,
molluscs, tadpoles, and small frogs and fish.
When
moult
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
ing at lakes with high salinity, although, this bird feeds mostly on brine shrimp. The behaviour of black-necked grebes changes in response to the availability of brine shrimp; bodies of water with more shrimp have more grebes, and grebes spend more time foraging when the amount of shrimp and the water temperature decreases.
The young are fed one at a time by the parents, with one bird carrying the young while the other feeds it. The young take food by grabbing it, with their beaks, from their parents, or by grabbing food dropped into the water. When a young bird cannot grab the food, then the adults submerge their bill into the water and shake their bill to break up the food.
Moult and migration
When breeding is over, the black-necked grebe usually partakes in a moult migration to saline lakes. It especially prefers lakes with large numbers of invertebrate prey, so it can fatten up while moulting and before going on its winter migration.
Some birds, although, moult when on the breeding grounds, but most do not moult until the end of the moult migration.
This migration is dangerous, with hundreds and sometimes thousands of birds being killed by snowstorms when traveling to places such as
Mono Lake
Mono Lake ( ) is a saline soda lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in an endorheic basin. The lack of an outlet causes high levels of salts to accumulate in the lake which make its water a ...
.
When it finishes its moult migration, this bird moults its
remiges
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...
between August and September,
which makes it unable to fly. This moult is preceded by an increase in weight. During the moult, the breast muscles atrophy. When the moult is completed, this grebe continues to gain weight, often more than doubling its original weight.
This additional fat is used to power the black-necked grebe's overnight fall migration to its wintering grounds. The fat is most concentrated in the abdomen, second most in the thorax, and least in the chest.
This bird usually starts its migration earlier when shrimp is more abundant and when the moulting lake is at a higher than average temperature. It generally leaves on a clear night with lower than average surface temperatures.
Movement
![Podiceps nigricollis diving](https://upload.wikimedia.org/wikipedia/commons/0/06/Podiceps_nigricollis_diving.JPG)
This grebe is one of the most inefficient fliers among birds. Generally, it avoids flying at all costs and reserves long-distance flight exclusively for migration.
This is combined with the fact that this bird is flightless for two months of the year during its moult.
However, when migrating, it travels as much as to reach rich feeding areas that are exploited by few other species.
In flight, the shape of this grebe is like a
loon: straight neck, legs trailing, and wings beating often.
When diving, this bird pulls its head back and then arches it forward into the water, with the body following and a slight springing. The legs start moving only after they are underwater. When swimming on the surface of the water, the body of this grebe is relatively high, although none of the underparts are seen. The neck is held straight up in a relaxed manner, with the bill being held forward and parallel to the water. Each of the feet perform strong alternating strokes.
Disease
Large-scale deaths (such as 150,000 birds on the Salton Sea in 1992) from
erysipelas
Erysipelas () is a relatively common bacterial infection of the superficial layer of the skin ( upper dermis), extending to the superficial lymphatic vessels within the skin, characterized by a raised, well-defined, tender, bright red rash, t ...
, avian cholera,
avian botulism,
and
West Nile virus
West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family '' Flaviviridae'', from the genus '' Flavivirus'', which also contains the Zika virus, dengue virus, and yellow fever virus. The v ...
have been recorded in the past. In 2013 at the Great Salt Lake, for example, there was an outbreak of West Nile virus which is among the largest recorded avian die-offs in the US.
The cause of the outbreak and modes of transmission are unknown, but there has been speculation about the latter. Since West Nile virus is able to survive in brine shrimp (and, for a temporary time, water at specific temperatures), it is likely that grebes could have become infected by eating diseased shrimp and/or swimming in the contaminated water.
It is also theorized that West Nile virus could be transmitted among grebes through contact with the excrement of an infected bird, possibly around bodies of water, communal nest sites, areas of cohabitating birds, etc.
Avian cholera, another disease that can cause massive die-offs in this species,
is transmitted by currently-unknown
biotoxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849– ...
s and/or pathogens, as well as problems with feather waterproofing putting birds at risk.
Status
As of 2016, the black-necked grebe is classified as least concern by the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...
(IUCN). The trend of the population is uncertain, as some populations are decreasing, whereas others are stable, have an uncertain trend, or are increasing. The justification for the current classification of this species is its very large population (estimated around 3.9–4.2 million individuals) combined with a large estimated extent of occurrence (about 155 million km
2 (60 million sq mi)).
This grebe is probably the most numerous grebe in the world.
Unknown
biotoxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849– ...
s, pathogens, and the impairment of feather waterproofing can lead to
hypothermia
Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe ...
and
avian cholera. Since this grebe usually winters on the coast, it is also vulnerable to oil pollution.
Large-scale disease, such as avian cholera, could threaten the species. These and other factors, such as human disturbance, including collisions with power transmission lines, contribute to declining populations in certain areas. This species used to be threatened in North America by the millinery industry, which helped facilitate the hunting of the birds, and egg collectors. Although this is true, this grebe is hunted in the
Gilan Province in Iran, for both commercial and recreational purposes. However, there is no evidence suggesting that these threats could result in a significant risk for the overall population.
References
Bibliography
*
External links
Eared Grebe Species Account– Cornell Lab of Ornithology
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black-necked grebe
The black-necked grebe or eared grebe (''Podiceps nigricollis'') is a member of the grebe family of water birds. It was described in 1831 by Christian Ludwig Brehm. There are currently three accepted subspecies, including the nominate subspecie ...
Birds of Africa
black-necked grebe
The black-necked grebe or eared grebe (''Podiceps nigricollis'') is a member of the grebe family of water birds. It was described in 1831 by Christian Ludwig Brehm. There are currently three accepted subspecies, including the nominate subspecie ...
Birds of Nepal
black-necked grebe
The black-necked grebe or eared grebe (''Podiceps nigricollis'') is a member of the grebe family of water birds. It was described in 1831 by Christian Ludwig Brehm. There are currently three accepted subspecies, including the nominate subspecie ...
Holarctic birds