Red-necked Grebe
Encyclopedia
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...
aquatic
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
bird found in the temperate regions of the northern hemisphere. Its wintering habitat is largely restricted to calm waters just beyond the waves around ocean coasts, although some birds may winter on large lakes. Grebe
Grebe
A grebe is a member of the Podicipediformes order, a widely distributed order of freshwater diving birds, some of which visit the sea when migrating and in winter...
s prefer shallow bodies of fresh water such as lakes, marshes or fish-ponds as breeding sites.
The Red-necked Grebe is a nondescript dusky-grey bird in winter. During the breeding season, it acquires the distinctive red neck plumage, black cap and contrasting pale grey face from which its name was derived. It also has an elaborate courtship display and a variety of loud mating calls. Once paired, it builds a nest from water plants on top of floating vegetation in a shallow lake or bog.
Like all grebes, the Red-necked is a good swimmer, a particularly swift diver, and responds to danger by diving rather than flying. The feet are positioned far back on the body, near the tail, which makes the bird ungainly on land. It dives for fish or picks insects off vegetation; it also swallows its own feathers, possibly to protect the digestive system. The conservation status
Conservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
of its two subspecies—P. g. grisegena found in Europe and western Asia, and the larger P. g. holboelii in North America and eastern Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
—is evaluated as Least Concern
Least 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...
, and the global population is stable or growing.
Taxonomy
Grebes are small to medium-large water birds with lobed, rather than webbed, toes. There are several generaGenus
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...
, of which the most widespread is Podiceps
Podiceps
Podiceps is a genus of birds in the grebe family.It has representatives breeding in Europe, Asia, North and South America. Most northern hemisphere species migrate in winter to the coast or warmer climates....
with nine species, one recently extinct. The Red-necked Grebe's closest relative is the fish-eating Great Crested Grebe
Great Crested Grebe
The Great Crested Grebe is a member of the grebe family of water birds.- Description :The Great Crested Grebe is long with a wingspan. It is an excellent swimmer and diver, and pursues its fish prey underwater. The adults are unmistakable in summer with head and neck decorations...
of Europe and western Asia. It is possible that the Red-necked Grebe originally evolved in North America and later spread to Europe, where a change of diet to include more insects helped to reduce competition with its larger cousin. Fossils of the species dating to the middle Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
have been found in Italy.
The genus name Podiceps comes from 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...
podicis, "vent" or "anus", and pes, "foot", and is a reference to the placement of a grebe's legs towards the rear of its body. The species name grisegena is from Latin griseus (grey) and gena (cheek) and refers to the face pattern of the breeding adult.
The Red-necked Grebe has two subspecies, the nominate subspecies P. g. grisegena in Europe and western Asia, and P. g. holboelii (Holboell's Grebe, named for Danish explorer of Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
ic birds Carl Peter Holbøll) in North America and eastern Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
. The east Asian birds have slightly smaller bills than the American form, although the differences are too small to merit separation as a third subspecies.
Description
The Red-necked Grebe is a medium-large grebe, smaller than the Great Crested Grebe of EurasiaEurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
, and the Western
Western Grebe
The Western Grebe, , is a species in the grebe family of water birds. Folk names include "dabchick", "swan grebe" and "swan-necked grebe"....
and Clark's Grebe
Clark's Grebe
Clark's Grebe is a North American species in the grebe family. Until the 1980s, it was thought to be a pale morph of the Western Grebe, which it resembles in size, range, and behavior...
s of North America. The adult of the nominate European subspecies is 40–50 cm (15.7–19.7 in) long with a 77–85 cm (30.3–33.5 in) average wingspan, and weighs 692–925 g
Gram
The gram is a metric system unit of mass....
(25–33 oz
Ounce
The ounce is a unit of mass with several definitions, the most commonly used of which are equal to approximately 28 grams. The ounce is used in a number of different systems, including various systems of mass that form part of the imperial and United States customary systems...
). In breeding plumage, it has a black cap that extends below the eye, very pale grey cheeks and throat, a rusty red neck, dark grey back and flanks, and white underparts. The eyes are dark brown and the long, pointed bill is black with a yellow base.
Slavonian Grebe
The Horned Grebe or Slavonian Grebe, Podiceps auritus, is a member of the grebe family of water birds. The Slavonian Grebe is an excellent swimmer and diver, and pursues its fish prey underwater...
, with a relatively larger bill and a grey, rather than white face. It is closer in size to the Eurasian Great Crested Grebe, but that species is longer-necked, has a more contrasting head pattern, and always shows white above the eye.
The sexes are similar in appearance, although the male averages heavier than the female. Chicks have a striped head and breast, and older juveniles
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
have a striped face, diffuse blackish cap, pale red neck and extensive yellow on the bill.
The subspecies P. g. holboelii is larger than the nominate race at 43–56 cm (17–22 in) length, with a 61–88 cm (24–35 in) wingspan, and a weight of 750–1,600 g (27–57 oz). The plumages are the same as those of the nominate race, although the adult's bill is more extensively yellow. The difference in size between the sexes is greater than for this subspecies that for P. g. grisegena.
The Red-necked Grebe flies with its long neck extended and its large feet trailing behind the body, which gives it a stretched-out appearance. The relatively small wings are grey with white secondaries, and beat very rapidly. Its small wing area means that the grebe is unable to take off from land, and needs a lengthy run across water to gain the speed needed for take-off. Like all grebes, the Red-necked is an expert swimmer; it uses its feet for propulsion underwater, and steers by rotating its legs, since its tail is too short for this purpose.
This is one of the most vocal grebes during the breeding season, but, like its relatives, it is mainly silent for the rest of the year. It has a loud, wailing or howling display call uooooh, given by a single bird or a pair in duet, by night or during the day, and often from cover. Long sequences of up to 60 consecutive notes may be delivered during singing encounters between rival territorial birds. A great variety of quacking, clucking, hissing, rattling and purring calls are also given, with much individual variation.
Distribution and habitat
Hectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
(6 acre
Acre
The acre is a unit of area in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre. The most common use of the acre is to measure tracts of land.The acre is related...
s) in extent and less than 2 m (6 ft) deep. The Red-necked Grebe shows a preference for waters in forested areas or, further north, in shrub tundra
Tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...
, and favours sites with abundant emergent vegetation
Emergent plant
An emergent plant is one which grows in water but which pierces the surface so that it is partially in air. Collectively, such plants are emergent vegetation....
, such as reedbeds
Reed bed
Reed beds are natural habitats found in floodplains, waterlogged depressions andestuaries. Reed beds are part of a succession from young reed colonising open water or wet ground through a gradation of increasingly dry ground...
. The best breeding habitat is fish-ponds, which have an abundance of food in addition to meeting the other requirements. The American subspecies is less tied to a high aquatic plant density, and sometimes breeds on quite open lakes.
All populations are migratory and winter mainly at sea, usually in estuaries and bays, but often well offshore where fish are within diving reach near shallow banks or islands. The preferred passage and wintering habitat is water less than 15 m (50 ft) deep with a sand or gravel bottom, scattered rocks and patches of seaweed. During winter, birds typically feed alone and rarely aggregate into flocks, but on migration, concentrations of over 2000 individuals may occur at favoured staging sites. Migration is usually at night, but may occur during the day, especially when over water. This is particularly noticeable in autumn on the Great Lakes, when up to 18,000 birds may pass Whitefish Point
Whitefish Point Bird Observatory
The Whitefish Point Bird Observatory is located in Chippewa County, Michigan, USA, adjacent to the Whitefish Point Unit of the Seney National Wildlife Refuge. It operates as a non-profit, affiliate education and research facility of the Michigan Audubon Society. The Society and the WPBO together...
on Lake Superior
Lake Superior
Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...
; these are thought to be Canadian breeders heading for the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
to winter. This easterly route is longer than that to the Pacific
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...
, but avoids the Rockies
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
.
The breeding range of the Red-necked Grebe overlaps with that of the Slavonian Grebe, although the latter species tends to be displaced from sites suited to both. The Red-necked Grebe prefers an inland temperate climate, and is less successful near coasts and in subarctic and warm temperate zones. It is usually a lowland bird, breeding below 100 m (330 ft), although has nested at up to 1800 m (5,900 ft) in Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
.
The nominate subspecies breeds from southern Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
and Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
through central and eastern Europe east to western Siberia, and winters mainly in the North
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
s, with smaller numbers in the Adriatic
Adriatic Sea
The Adriatic Sea is a body of water separating the Italian Peninsula from the Balkan peninsula, and the system of the Apennine Mountains from that of the Dinaric Alps and adjacent ranges...
, Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
, Caspian Sea
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
, Mediterranean
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
and on inland lakes. P. g. holboelii breeds in North America 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...
, western and central Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and the northern USA east to Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
; in Asia it nests in eastern Siberia from Kamchatka
Kamchatka Peninsula
The Kamchatka Peninsula is a peninsula in the Russian Far East, with an area of . It lies between the Pacific Ocean to the east and the Sea of Okhotsk to the west...
south to Hokkaido
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 west to Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
. The Asian birds winter at sea from 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...
to the East China Sea
East China Sea
The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...
, and American breeders winter in the Pacific, mainly from southern Alaska to British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
(with smaller numbers south to 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...
), and in the Atlantic from Newfoundland and Labrador
Newfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. Some birds remain on the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
if they are sufficiently ice-free. This species occurs as a rare winter vagrant
Vagrancy (biology)
Vagrancy is a phenomenon in biology whereby individual animals appear well outside their normal range; individual animals which exhibit vagrancy are known as vagrants. The term accidental is sometimes also used...
in Afghanistan, Pakistan and parts of northern and western India.
Breeding and survival
Red-necked Grebes usually nest as isolated pairs with more than 50 m (160 ft) between neighbouring nests, although semi-colonial nesting may occur in suitable sites, where up to 20 pairs each defend a linear territory. Semi-colonial breeding is more likely to occur in prime locations, such as large floating mats of vegetation with no connection to the shoreline. Such sites, safe from most predators and large enough to provide some wind and wave protection, have grebes nesting much closer than shoreline breeders, down to 10 m (33 ft). Pairs nesting in these colonies produce larger clutches of eggs, which hatch earlier in the season and result in larger broods. The territory is defended with various threat displays, including wing-spreading, hunching, and bill-thrusting; pairs breeding in colonies are more aggressive, less likely to leave the nest unguarded and show a greater tendency to move out of sight of the colony when not incubating. Breeding is often in loose association with gullGull
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 or other colonial water birds.
Monogamy
Monogamy /Gr. μονός+γάμος - one+marriage/ a form of marriage in which an individual has only one spouse at any one time. In current usage monogamy often refers to having one sexual partner irrespective of marriage or reproduction...
pair forms in April or May on migration or at the breeding water, and a highly vocal courtship ritual commences. The elaborate breeding performance includes head-shaking, a head-lowered "cat" display, parallel rushes in an upright position and mutual presentations of green weeds, and culminates in a "penguin" dance in which pair members raise the whole body upright, breast to breast.
Like all grebes, the Red-necked Grebe nests near water into which it can escape, since the position of the legs far back on the body prevents fast movement on land. It often breeds further within reed beds than other grebes. The nest is a floating platform of plant matter anchored to submerged or emergent vegetation, in water 0.5–0.75 m (19–29 in) deep, and with the bulk of nest below the water line. Egg-laying mainly takes place from mid-April to May in Europe, and somewhat later, from mid-May to June, in North America. Parents may leave the nest for significant periods of time during the night, possibly to evade nocturnal predators. It is unclear whether this is for self-protection or to protect the eggs by diverting attention from the nest; the clutch does not appear to suffer from this temporary abandonment, whatever the reason.
.jpg)
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
the eggs for 21–33 days until the precocial
Precocial
In biology, the term precocial refers to species in which the young are relatively mature and mobile from the moment of birth or hatching. The opposite developmental strategy is called "altricial," where the young are born or hatched helpless. Extremely precocial species may be called...
downy chicks hatch; they immediately climb onto the parent's back, where they spend most of their time until they are 10–17 days old. The young may be fed by the parents for up to 54 days after fledging, and can fly at 50–70 days. The parents do not interfere with the feeding of their chicks when they are still being carried. Later they care for the younger chicks for longer, and are aggressive with the older offspring. This equalises the post-fledging survival of all chicks, and encourages their independence. The brood may be split, so that each parent feeds only some of the chicks. This spreads the feeding demand equally between the parents.
After breeding the adults moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
their wing feathers and are temporarily flightless; migration commences once the flight feather
Flight feather
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
s have regrown. The Red-necked Grebe is normally single-brooded, although second broods and re-nesting after a clutch has been lost may extend nesting into July or August.
Eggs may be destroyed and chicks killed by a range of predators, including the raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
in North America and the Carrion Crow
Carrion Crow
The Carrion Crow is a member of the passerine order of birds and the crow family which is native to western Europe and eastern Asia.-Taxonomy:...
in Europe. Pike
Esox
Esox is a genus of freshwater fish, the only living genus in the family Esocidae — the esocids which were endemic to North America, Europe and Eurasia during the Paleogene through present.The type species is E. lucius, the northern pike...
may take swimming chicks. On average, for each adult, 0.65 young birds are still alive by their fourth month, although the mortality rate for the adult is unknown. Red-necked Grebes attempt to evade birds of prey
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
by diving; when feeding, dives average less than 30 seconds, although escape dives are more prolonged.
Feeding
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s including adult and larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l aquatic insects, such as water beetle
Water beetle
A water beetle is a beetle adapted to living in water. Water beetles rise to the water surface and take atmospheric air into their tracheal systems. There are approximately 2000 species of water beetles. The rest marine species tend to live in the intertidal zone...
s and dragonfly
Dragonfly
A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...
larvae, crayfish
Crayfish
Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...
and molluscs. Fish (such as smelt) may be important locally or seasonally, especially for the American subspecies, and crustacean
Crustacean
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 can constitute up to 20% of the grebe's diet. Birds breeding at the coast often make foraging flights to inland lakes or offshore areas to feed.
Aquatic prey is obtained by diving or by swimming on surface with the head submerged, and terrestrial insects and their larvae are picked off vegetation. A line slanting downward from the eye to the tip of the opened lower mandible may be used for sighting on prey before diving or when swimming under water. The grebe probably opens its bill and looks down the eye-line toward its target.
European breeders, which have to compete with the larger Great Crested Grebe for fish, eat a greater proportion of invertebrates than the longer-billed American subspecies, although both races eat mainly fish in winter. Birds of the nominate subspecies from the northernmost breeding populations in Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
and Russia, beyond the range of Great Crested Grebe, have a longer and more slender bill than those further south, reflecting a greater proportion of fish in the diet where their main competitor is absent. If food is scarce, parents may desert unhatched eggs, or allow the smallest chicks to starve, although the latter strategy appears not to be particularly efficient in protecting the older chicks.
Like other grebes, the Red-necked Grebe ingests large quantities of its own feathers, which remain in the bird's stomach. Feathers are not only swallowed by adults, mainly during self-preening, but are often fed to the young, sometimes within a day of hatching. These feathers soon decompose into a felt-like, amorphous mass. The function of the feathers in the stomach is unknown, although it has been suggested that they help to protect the lower digestive tract from bones and other hard, indigestible material.
Status
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. For these reasons, the species is evaluated as Least Concern
Least 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...
.
The Red-necked Grebe is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA
AEWA
The Agreement on the Conservation of African-Eurasian Migratory Waterbirds is the largest of its kind developed so far under the Bonn Convention. It was concluded on 16 June 1995 at The Hague, the Netherlands and entered into force on 1 November 1999 after the required number of at least fourteen...
) applies. Parties to the Agreement are required to engage in a wide range of conservation strategies which are describes in a detailed action plan. The plan is intended to address key issues such as species and habitat conservation, management of human activities, research, education, and implementation.
The Red-necked Grebe was hunted by humans in northern Europe in the Mesolithic
Mesolithic
The Mesolithic is an archaeological concept used to refer to certain groups of archaeological cultures defined as falling between the Paleolithic and the Neolithic....
and Paleolithic
Paleolithic
The Paleolithic Age, Era or Period, is a prehistoric period of human history distinguished by the development of the most primitive stone tools discovered , and covers roughly 99% of human technological prehistory...
periods, but there is no evidence that there is any significant level of hunting at the present time. In North America, there are potential threats from pollutants such as polychlorinated biphenyls (PCBs) and pesticides such as DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
which cause reduced reproductive success due to egg sterility and eggshell thinning. Breeding areas may be threatened by the modification and degradation of lakes and by human disturbance from water-based recreational activities. There is no evidence to suggest that these threats could result in a significant risk to the overall population; more than 70% of North American Red-necked Grebes breed in Canada, where the population is stable or increasing.
External links
- USGS – Red-necked Grebe Information
- South Dakota Birds – Red-necked Grebe Information and Photos
- Flicker Field Guide Birds of the World Photographs
- Red-necked Grebe videos on the Internet Bird Collection