Red-necked grebe

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Red-necked grebe
Red-necked grebe in magnificent dress

Red-necked grebe in magnificent dress

Systematics
Class : Birds (aves)
Order : Grebes (Podicipediformes)
Family : Grebes (Podicipedidae)
Genre : Diver ( podiceps )
Type : Red-necked grebe
Scientific name
Podiceps grisegena
( Boddaert , 1783)

The Red-necked Grebe ( Podiceps grisegena ) is a bird art from the family of grebes (Podicipedidae). The Holarctic range of the species includes parts of northern Eurasia and northern North America. In Eurasia the distribution is divided into several subareas, the western closed distribution area extends from eastern Central Europe to western Siberia.

Like all grebes, the red-necked grebe is a good swimmer and skilled diver. In summer, its food consists mainly of aquatic insects and their larvae as well as mollusks, crustaceans and frogs. In winter, fish play a slightly larger role in his diet. The species usually breeds in small, shallow bodies of water with well-developed bank vegetation. The red-necked grebe is a partial and short-distance migrant who stays from late autumn to spring on deep lakes and in bays with no major waves. The red-necked grebe is considered stable to slightly increasing.

Appearance

There are two subspecies of the red-necked grebe: the nominate form P. g. grisegena occurs in Europe and western Asia, the somewhat larger subspecies P. g. holboellii is common in North America and Eastern Siberia.

Appearance of colored red-necked grebes

Red-necked grebe
Great crested grebe - distinguishing features from the red-necked grebe are, among other things, the pronounced feather bonnet and the light-colored plumage in front of the eye

The red-necked grebe is a medium-sized grebe that is slightly smaller and shorter-necked than the great crested grebe. Adult red-necked grebes of the nominate form widespread in Eurasia reach a body length between 40 and 50 centimeters with a wing span between 77 and 85 centimeters. Your body weight is between 692 and 925 grams. Representative of the North American subspecies P. g. holboellii are slightly larger than the nominate form and reach a body length of 42 to 56 centimeters. They weigh between 750 and 1600 grams. There is only a slight sexual dimorphism , males are only slightly larger than females. The difference in size is somewhat more pronounced in the North American subspecies than in the nominate form. Within the subspecies P. g. holboellii , the East Asian red-necked grebes have a slightly narrower beak than the divers common in North America.

In summer, birds in their splendid plumage are easy to spot. The front neck, the sides of the neck and the goiter area are rust-red. The back of the neck and the top of the body are black-brown. The back feathers have a narrow, light brown border. The chest and stomach, on the other hand, are whitish. The sides of the chest and the flanks have coarse gray-brown spots. The tail is black. The wings are gray-brown with black spring shafts. The arms, on the other hand, are white. The spring shafts are black at the base and white towards the tip. They have a variable brown pattern. The innermost arm wings and the shoulder feathers are completely brown. The throat and cheeks are light gray. They are set off from the neck and the black skull by a white line. The black headstock extends down over the eyes. Some dark head feathers are somewhat elongated so that small feather ears can be seen. The beak is yellow at the base, otherwise black. The eyes are dark brown. The two subspecies show no differences in plumage. In the North American subspecies, however, the yellow of the beak base is a little more pronounced.

Red-necked grebe in simple dress

Adult red-necked grebes change to plain dress from July . In this full moult they are unable to fly for a short time and then live very hidden. The plain dress is a little grayish than that of other grebes. The border between the dark head cap and the gray face is more diffuse during this time. The spring ears are missing. The sides of the head, chin and throat are white. The head plumage is speckled gray-brown under and behind the eye. The front neck is whitish to light gray, the rear neck is darker gray. The rest of the top of the body is dark gray-brown and the feathers have a hem that is slightly lighter than in the magnificent dress. The wings are colored like in a splendid dress, but the innermost arm wings and the arm covers are gray-brown. The yellow of the beak is less pronounced. The flanks are mouse gray. The underside of the body is whitish. The moult into the magnificent dress begins in December. It mainly includes the head and neck plumage. Red-necked grebes in transition dress can be observed until the end of March.

Flight image, swimming and comfort behavior

Red-necked grebes fly with their necks extended and feet extended backwards. They usually fly at a height of 20 to 30 meters. The relatively small wings are gray and white. The wing beat is very fast. Because of their small wings, red-necked grebes are unable to fly up on land. On the water, they need a long run-up to get up to speed enough to rise into the air. Like all grebes, they are excellent swimmers who, due to the low level of pneumatization of the skeleton, lie relatively deep in the water. To submerge in the water, they make a powerful leap forward, during which they occasionally emerge with their entire body out of the water. The wings remain in place under water. The powerful legs and feet serve as drive and rudder under water.

Resting red-necked grebes retract their necks or stick their beak into the feathers on the back neck. The feet are often on the body under the wings. Cleaning red-necked grebes poke their feathers with their bills and nibble through individual feathers with rapid beak movements. They often turn sideways in the water so that the light belly side is visible from afar.

Appearance of the chicks and fledglings

Young red-necked grebe with the characteristic longitudinal stripes on the head and neck

The downy coat of the chicks is short and dense with a characteristic black and white longitudinal stripe on the head and neck. There are three naked scarlet spots on the head. These are located on both sides of the base of the beak and a third on the crown. It is surrounded by a white parting that tapers off at the back of the head. The two dark stripes that surround it are slightly wider. The neck stripes are brownish white. The neck has narrow, dark stripes that are somewhat blurred in the upper shoulder region. On the sides of the neck, the stripes are even interrupted in the middle. The back and the flanks, on the other hand, are unstriped. The middle underside of the body is white. The iris is olive brown. The beak is bluish pink with a white tip. Two vertical black bands run around the two halves of the beak. One of these can be found at the base of the beak and a second immediately behind the tip of the beak. The legs are dark gray. The toes are olive gray.

The sides of the head and chin are dirty white in youthful clothes. Two striking black-brown stripes run behind the eye. A dark spot is found at the base of the lower mandible. The chin and throat are also darkly mottled. The neck is yellow-brown. The underside of the body is indistinctly spotted. The wings already have the coloration of adult red-necked grebes, but the white arm wings sometimes have a stronger brown tip speckle.

Possible confusion with other bird species

Red-necked grebes in splendid plumage are unmistakable in Europe. The red neck color is missing in the plain dress, so the red-necked grebe can be confused with both the eared grebe and the great crested grebe. However, the red-necked grebe is roughly twice as large as the eared grebe. The red-necked grebe differs from the great crested grebe in that it is much more compact. Its neck, more gray in color, is also shorter and thicker. The main distinguishing feature, however, is the extent of the black headstock. The beak is also more compact and the head a bit more rounded.

Voice and instrumental sounds

Courting red-necked grebes

The red-necked grebe is extremely shouting during the breeding season. Outside of the breeding season it is mostly mute. At the beginning of the breeding season, a piercing, foal-like neigh is characteristic, which sounds like uöö-uööö .... This typical call can be heard day and night, sometimes in a duet of two birds at the same time. The individual call series, which are heard especially in territorial disputes with other red-necked grebes, can be very long. Call duets are occasionally performed for over an hour. The call is sometimes interrupted by a quick, cheeky kek-kek-kek .

Courting red-necked grebes give a sustained, mallard-like aak-aak ... or ec ec ec ... in addition to the cheeky calls . The sound sequences, which usually consist of four to ten aak , are always structured. After every two to five tones, the birds pause briefly so that a sound sequence like aakaak-aakaak-aakaakaak-aakaak-aakaak-aakaakaak sounds. Red-necked grebes , who are concerned, warn with a short, hard ack or boldly . If you are very worried, the calls will be heard every half a second. Red-necked grebes sitting on the nest hiss like a snake when a predator approaches. Young red-necked grebes beg their parent birds with ti ti tü ti tü ... calls for food. They also let you hear a bi bi bi .. or zipp zipp .. as a voice feeler .

The noisy spray diving with which the eared grebe and the black-necked grebe warn of approaching enemies occurs only rarely in the red-necked grebe . The only noticeable instrumental sound of the red-necked grebe is the noisy flight over the surface of the water when they fly up due to enemy interference.

distribution

Breeding area

Distribution of the red-necked grebe:
  • Breeding areas
  • Year-round occurrence
  • Wintering areas

    • Red-necked grebes are widespread and regionally frequent breeding birds in the northern hemisphere. Their breeding area covers an area of ​​continental climatic zones, which is between 35 and 65 ° N. In the north of Finland and in the north-west of Russia, where they breed on the White Sea , they also occur north of the 67th parallel. In Central Asia, their breeding area shows a large distribution gap.

    Red-necked grebes are predominantly breeding birds of the northern prairie and steppe zones as well as the Strauchtundra . In the winter months they rest in estuaries and sea bays. However, they can also be found far away from the coast in shallow water zones or near islands, where fish can be found at an accessible depth.

    Distribution of the nominate form

    The closed distribution area of ​​the nominate form extends from eastern Central Europe and central Scandinavia to western Siberia. The western limit of distribution runs through Germany roughly along the Elbe . To the west of this border there were isolated breeding records in the Netherlands and Great Britain . In the south the area extends to Romania , Macedonia , Turkey and Transcaucasia . Both in the south and in the west the distribution area is disjoint .

    Red-necked grebe of the nominate form

    In Austria , the species still occurred as a breeding bird on Lake Neusiedl and in the Danube floodplains east of Vienna in the first half of the 19th century . As a breeding bird, the red-necked grebe has largely disappeared there.

    Distribution of P. g. holboellii

    The subspecies P. g. holboellii breeds in North America in Alaska , in western and central Canada as well as in the US states Washington , Montana and Minnesota . Single breeding pairs are also found in Iowa , Michigan, and New Hampshire . In Asia, this subspecies breeds in Eastern Siberia . The breeding area extends from Kamchatka to Hokkaidō and western Mongolia . Isolated breeding populations can be found in the area of Lake Balkhash in eastern Kazakhstan and in Kyrgyzstan .

    hikes

    Large parts of the northern Swedish, Finnish and Russian populations cross the Scandinavian peninsula on their migration and overwinter on the Norwegian Atlantic coast between 63 and 65 ° N. So far, however, there are no breeding records for Norway. Many red-necked grebes also overwinter in the Baltic Sea and in the coastal waters of Denmark. Only in the last few years has it been established on the basis of aerial photographs and ship observations that red-necked grebes often stay far away from the coast in the Baltic Sea. They prefer to gather in places with a water depth of 5 to 20 meters, sandy bottom and seaweed vegetation .

    Red-necked grebes also overwinter in smaller numbers on the Adriatic , Aegean , Aral , Black and Caspian Seas . They appear on the Assov Sea and the South Caspi in September and leave them again at the end of March. In the inland they are regular migrants and occasionally also come to inland lakes as winter guests.

    The East Asian red-necked grebes overwinter on the coast of Japan to the coast of the East China Sea . The Kyrgyz and Kazakh breeding populations, on the other hand, overwinter in Afghanistan and increasingly also in northwest India . The North American breeding birds overwinter on the Pacific coast from southern Alaska to British Columbia . A small number of red-necked grebes can be found on the California coast during the winter months . On the Atlantic coast, the wintering area extends from Newfoundland to Florida . Some red-necked grebes overwinter at the Great Lakes , provided that they remain sufficiently free of ice.

    habitat

    Wallnau water bird reserve on the island of Fehmarn . Red-necked grebes breed here regularly

    Red-necked grebes breed in the dense reed bed , provided this has small, open water areas, on small, densely overgrown ponds and on shallow lakes with rich aquatic vegetation. The breeding waters can either be in open terrain or be completely enclosed by the forest. Waters colonized by red-necked grebes often have a water surface of less than three hectares and a water depth of less than two meters. In Canada's Northwest Territories , the average size of bodies of water inhabited by red-necked grebes is 2.4 hectares. In the Saxon breeding area, the minimum water body size is 1.5 hectares. Smaller ponds of 0.3 to 1.5 hectares are usually only populated within larger pond complexes.

    Red-necked grebes find ideal conditions in fish ponds, which have a rich supply of food and in Central Europe this is the most common type of water body populated by red-necked grebes. The competition with the great crested grebe most likely contributes to the fact that red-necked grebes are often found in small bodies of water that are not inhabited by this grebes species. But even where great crested grebes do not occur, red-necked grebes show a preference for small and shallow waters.

    Sometimes red-necked grebes breed in small bodies of water near the coast and look for food on the coast.

    nutrition

    Red-necked grebes almost exclusively prey on their food under water or read it from the surface of the water. A fine line that leads from the eye to the tip of the lower mandible when the beak is open will probably help them fix their prey. Red-necked grebes often eat fish, but aquatic invertebrates play a larger role in their diet . These include insects such as water beetles and dragonfly larvae , crustaceans and mollusks . Vegetable food, like the eggs of invertebrates, is likely to be consumed by chance. In gastric analyzes of Kazakh red-necked grebes, they contained 78.3 percent water beetles, but only 0.03 percent fish. The proportion of fish in Estonian red-necked divers was slightly higher at two percent. However, fish such as smelt and butterfish and, in the marine environment, sea ​​gobies ( Gobius ), haddock and sticklebacks ( Gasterosteus and sea stickleback ) can play an important role locally and seasonally. An examination of the stomach contents of red-necked grebes in Denmark showed that they rarely eat fish over 15 centimeters in size. Fish play mainly for the slightly larger subspecies P. g. holboellii play a role. However, this subspecies also breeds regularly in fish-free waters. There leeches are probably the main component of the diet.

    Red-necked grebes spend more time eating than other European podiceps species. Given their size, this is probably a result of their specialization in invertebrates. The lower proportion of fish in the diet of the nominate form is attributed to the food competition with the larger great crested grebe. The red-necked grebes of the nominate form, which breed north of the great crested grebe in Finland and Russia, have a slightly larger beak than those which breed further south. These red-necked grebes have a larger proportion of fish in their diet. The greater beak length is considered to be an adaptation to this slightly different food composition.

    Especially in winter it has been observed that velvet ducks sometimes go looking for food together with red-necked grebes, especially over sandy bottom. Presumably, during these dives, mainly poly-bristles are scared off (on average> 1000 per square meter) and ingested by both species.

    Reproduction

    “Presentation of material”, one of the poses of pairing behavior
    Red-necked Grebe at the nest
    Red-necked grebe with chicks on its back

    Courtship

    Some red-necked grebes return to the breeding areas already mated. For most of them, however, pairing only takes place in the closer breeding area. The pairing behavior has numerous elements that can also be observed in the great crested grebe. Red-necked grebes are very shouting at this time.

    The behavioral elements include shaking the head accompanied by loud shouts. The beak is held diagonally downwards. The extended head feathers are strongly ruffled. The birds also shout out loud while they swim towards each other when “presenting material”, another ritualized element of behavior. In the so-called "penguin pose", the red-necked grebe lift their front body far out of the water while they violently tread water. This behavior element ends when the two birds sink back onto the water with their heads turned away from each other. Red-necked grebes also show the so-called “ghost pose”, but this behavioral element is less frequently observed in them than in the great crested grebe. This element is mainly carried out by females, who first dive and then very slowly emerge from the water at some distance. The neck is curved in an S-shape. The beak rests on the chest, the elongated head feathers are heavily ruffled and the abdominal plumage is fluffed.

    Nest and rearing of the young

    Egg ( Museum Wiesbaden Collection )

    Red-necked grebes usually breed individually. There are breeding colonies, but they never reach the size typical of black-necked grebes and great crested grebes. Colony formation occurs primarily in waters that offer the red-necked grebe ideal conditions. But also here no more than four pairs breed per 10 hectares. Red-necked grebes in such colonies usually have somewhat larger clutches and start breeding earlier. The territory is defended aggressively against the other couples. Red-necked grebes like to set up their breeding ground in the middle or on the edge of a colony of gulls or terns . Their nests are often found near coots or ducks .

    The nest is often further from the shore line than is characteristic of other grebes. It is a floating or shallow pile of rotting aquatic and riparian plants. It is believed that the heat of putrefaction favors the brood. The nest is lower than that of the great crested grebe and has a small hollow on the top. The nesting material is brought to the nest by swimming from a short distance. The nest building continues even while the eggs are being laid. Both sexes are involved in the construction.

    Egg-laying begins at the end of April and can drag on until the beginning of June. Red-necked grebes usually raise only one brood per breeding period. If the clutch is lost, place up to five additional clutches. Very rarely there is a second annual brood. The full clutch usually contains four to five eggs, rarely only two or up to seven eggs. The eggs are tapered at both ends. The shell is smooth and white. The laying interval is two days. Both parent birds breed. Incubation probably begins when the first egg is deposited. The breeding season is 20 to 23 days. The parent birds very often leave the nest during the night. It is not clear whether red-necked grebes avoid nocturnal predators or whether this behavior contributes to the fact that the nest is not discovered. In any case, the eggs do not seem to be damaged by the breeding breaks.

    The chicks climb onto their parents' backs shortly after hatching. They spend a large part of the day there, until they are 10 to 17 days old. The young begin to feed themselves in the fourth week of life, but are fed by the parent birds until the sixth and seventh weeks of life.

    Causes of mortality

    The eggs and chicks are eaten by a number of predators. In North America, the raccoon is an essential predator. However, it only reaches the nests that are near the shore line. In Europe, clutches and young birds are mainly eaten by the carrion crows . Also herons and rallidae eat the eggs of the Red-necked Grebe. The chicks are also eaten by large freshwater fish such as pike . On average, towards the end of summer there are 0.65 young birds for every adult breeding bird.

    Insufficient data are available on the mortality rate of adult red-necked grebes. But they are beaten by a number of predators on the nest and also on the water. The predators include large owls , peregrine falcons , hawks and sparrowhawks, as well as various species of sea ​​eagles and harriers .

    Inventory and status

    The red-necked grebe is one of the species covered by the provisions of the Convention for the Conservation of Migratory African-Eurasian Waterfowl . Signatory states to this partial treaty of the Bonn Convention have promised to take measures to protect migratory water bird species and to protect their habitats.

    According to the IUCN, the red-necked grebe has a range of 1,000,000 to 10,000,000 square kilometers. The global population is estimated at 150,000 to 370,000 individuals. The population development of the species is not quantified by the IUCN and classified as least concern or not threatened . The ornithologist and editor of the standard work The Grebes (Die Lappentaucher), published in 2004, Jon Fjeldså describes the population as stable. However, the population figures fluctuate in many regions of the world. The population in the Czech Republic and in individual regions of European Russia has decreased. However, there are indications that they are increasing in many other regions: the number of red-necked grebes in Finland has doubled or tripled in the last few decades and the number of red-necked grebes that winter in the Caspian Sea has also increased. In Denmark, the breeding population increased fivefold from the 1960s to the 1990s. The total European population west of the Urals is estimated to be around 32,000 to 56,000 breeding pairs. Of these, between 1,500 and 2,600 pairs breed in Germany. For the subspecies P. g. holboellii there are no more accurate population estimates, but the number of individuals is certainly more than 100,000 birds.

    Adult red-necked grebe with young

    The red-necked grebe is one of the species that is particularly affected by marine pollution from crude oil or heavy oil . This is due to the fact that they overwinter in concentrated numbers in a few places. For example, the wreck of an oil tanker in the Baltic Sea in February 1979 led to the death of around 800 red-necked grebes as a result of oil pollution. At that time, this number corresponded to 50 percent of the breeding population in Sweden and Denmark. Both populations took more than five years to recover from the oil spill . One of the recommended protective measures of the IUCN group of specialists for grebes is therefore to place important wintering areas under protection for the red-necked grebe.

    The hunt for the red-necked grebe does not pose a threat to the population today. The red-necked grebe was an important prey in northern Europe during the Palaeolithic and Mesolithic times , but there is no evidence today that the hunt is still taking place in any significant way. In North America, the red-necked grebe was one of the species whose reproductive rate declined as a result of DDT exposure . Habitat changes caused by humans also have an impact on the population. However, a large part of the population breeds in regions of the world that have so far only been opened up to a limited extent by humans.

    The red-necked grebe is one of the species that will be particularly hard hit by climate change. A research team that, on behalf of the British Environmental Protection Agency and the Royal Society for the Protection of Birds, examined the future distribution of European breeding birds on the basis of climate models, assumes that the range of the red-necked grebe will change significantly by the end of the 21st century . According to this prognosis, the distribution area will decrease considerably and at the same time shift to the north. Three quarters of today's distribution area no longer offers the red-necked grebe suitable habitats. In Central Europe , the species will largely be absent as a breeding bird. The possible future distribution areas include large parts of Fennoscandinavia, in which the species is currently not represented.

    Systematics

    Grebes are small to medium-sized, water-bound birds whose toes are not webbed but have wide flaps. The name Podiceps for the genus is derived from the two Latin terms podex for butt and pes for foot . This is an indication that the grebes' legs are positioned far back on the body. The specific epithet grisegena is derived from the French word gris (= gray) and the Latin gena (= cheek).

    The subspecies P. g. holbollii is named after the Danish natural scientist Carl Peter Holböll . The East Asian and North American divers of this subspecies show slight deviations in the shape of the beak, but the differences are too small to justify the separation of a third subspecies.

    The red-necked grebe is most closely related to the great crested grebe. It is believed that the red-necked grebe originally developed in North America and only later spread to Europe and western Asia. An adjustment in the food composition, which today has a significantly higher proportion of insects than in the great crested grebe, has reduced food competition with the somewhat larger relative. Fossil finds that can be dated to the middle Pleistocene were found in Italy.

    literature

    • Hans-Günther Bauer, Einhard Bezzel and Wolfgang Fiedler (eds.): The compendium of birds in Central Europe. Everything about biology, endangerment and protection. Volume 1: Nonpasseriformes - non-sparrow birds. Aula-Verlag Wiebelsheim, Wiesbaden 2005, ISBN 3-89104-647-2 .
    • Einhard Bezzel: birds. BLV Verlagsgesellschaft, Munich 1996, ISBN 3-405-14736-0
    • Jon Fjeldså: The Grebes . Oxford University Press, 2004, ISBN 0198500645
    • VD Il'ičev & VE Flint (eds.): Handbook of birds of the Soviet Union - Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . Aula Verlag, Wiesbaden 1985, ISBN 3-89104-414-3
    • André Konter: Grebes of our world , Lynx Edicions, Barcelona 2001, ISBN 84-87334-33-4
    • Günther Niethammer (Hrsg.): Handbook of the birds of Central Europe. Volume 1: Gaviformes - Phoenicopteriformes. Edited by Kurt M. Bauer and Urs N. Glutz von Blotzheim , Akademische Verlagsgesellschaft, Wiesbaden 1966.
    • MA Ogilvie and Chris Rose: Grebes of the World , Bruce Coleman Books, New York 2002, ISBN 1872842038

    Web links

    Wiktionary: Red-necked grebe  - explanations of meanings, word origins, synonyms, translations
    Commons : Red-necked Grebe  - Album with pictures, videos and audio files

    Individual evidence

    1. ↑ David Snow and Christopher Perrins (Eds.): The Birds of the Western Palearctic , Oxford University Press, Oxford 1998, ISBN 019854099X , pp. 17-20
    2. ^ David Sibley: The North American Bird Guide , Pica Press, 2000, ISBN 1873403984 , p. 29
    3. ↑ a b c Einhard Bezzel: Birds. BLV Verlagsgesellschaft, Munich 1996, ISBN 3-405-14736-0 , p. 74
    4. ↑ a b c d e David Snow and Christopher Perrins (eds.): The Birds of the Western Palearctic , Oxford University Press, Oxford 1998, ISBN 019854099X , pp. 20-22
    5. ^ Ogilvie & Rose (2002) 92
    6. ^ Jon Fjeldså: The Grebes . Oxford University Press, 2004, ISBN 0198500645 , p. 181
    7. ↑ a b c Ogilvie & Rose (2002) 57-60
    8. ↑ a b Niethammer (1966), p. 119
    9. ^ Niethammer, p. 118
    10. ↑ a b Konter, p. 109
    11. ↑ a b c Killian Mullarney, Lars Svensson, Dan Zetterstrom, Peter Grant: Collins Bird Guide , HarperCollins, London 1999, ISBN 0002197286 , p. 18
    12. ↑ a b Red-necked Grebe . In: BirdFacts . Cornell Laboratory of Ornithology. Retrieved February 6, 2011.
    13. ↑ a b c Niethammer (1966), p. 120
    14. ↑ Fjeldså, p. 140
    15. ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union - Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 262
    16. ↑ Fjeldså, p. 31
    17. ^ Paul A. Johnsgard: Diving Birds of North America , University of Nebraska, Lincoln 1987, ISBN 0803225660 , pp. 26-36
    18. ↑ Fjeldså, p. 10
    19. ^ Niethammer (1996), p. 127
    20. ↑ a b c Niethammer (1966), p. 121
    21. ↑ a b c d e Fjeldså, p. 182
    22. ↑ Hans-Heiner Bergmann; Hans-Wolfgang Helb; Sabine Baumann; The voices of the birds of Europe - 474 bird portraits with 914 calls and chants on 2,200 sonograms , Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1 ; P. 99
    23. ↑ Hans-Heiner Bergmann; Hans-Wolfgang Helb; Sabine Baumann; The voices of the birds of Europe - 474 bird portraits with 914 calls and chants on 2,200 sonograms , Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1 ; P. 100. This source was followed in the onomatopoeic description of the calls.
    24. ↑ a b c d e Fjeldså, p. 183
    25. ^ Niethammer (1966), p. 123
    26. ↑ a b Fjeldså, p. 50
    27. ↑ a b Harrison (1988), p. 217
    28. ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union - Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 266
    29. ↑ BirdLife International Species factsheet: Podiceps grisegena . BirdLife International. Retrieved February 6, 2011.
    30. ↑ a b Niethammer (1966), p. 125
    31. ↑ Janusz Kloskowski: Food provisioning in red-necked grebes ( Podiceps grisegena ) at common carp ( Cyprinus carpio ) ponds . In: Hydrobiologia . 525, 2004, pp. 131-138. doi : 10.1023 / B: HYDR.0000038860.37405.d0 .
    32. ↑ a b c Bauer et al., P. 189
    33. ^ Robert W. Ficken, Matthiae, Paul E .; Horwich Robert: Eye Marks in Vertebrates: Aids to Vision . In: Science . 173, No. 4000, September 1971, pp. 936-939. doi : 10.1126 / science.173.4000.936 .
    34. ↑ a b c d e Fjeldså, p. 184
    35. ↑ Piersma, T: size body, nutrient reserves and diet of red-necked grebes and Slavonian Podiceps grisegena and P. auritus on Lake IJsselmeer, The Netherlands . In: Bird Studies . 35, No. 1, 1988, pp. 13-24.
    36. ↑ a b Niethammer (1966), p. 126
    37. ^ A b c Paul A. Johnsgard: Diving Birds of North America , University of Nebraska, Lincoln 1987, ISBN 0803225660 , pp. 130-135
    38. ↑ Jon Fjeldsa: The adaptive significance of local variations in the bill and jaw anatomy of North European red-necked grebes Podiceps grisegena . In: Ornis Fennica . 59, No. 2-3, 1982, pp. 84-89.
    39. ↑ Ingvar Byrkjedal, Steinar Eldoy, Svein Grundetjern, Mass K. Loyning: Feeding associations between Red-necked Grebes Podiceps griseigena and Velvet Scoters Melanitta fusca in winter . In: Ibis , Vol. 139, No. 1, January 1997, pp. 45-50, doi : 10.1111 / j.1474-919X.1997.tb04503.x .
    40. ^ Niethammer (1966), p. 128 and p. 129
    41. ↑ Gary L. Nuechterlein, Buitron, Deborah; Sachs, Joel L .; Hughes, Colin R .: Red-necked grebes become semicolonial when prime nesting substrate is available . In: The Condor . 105, No. 1, February 2003, pp. 80-94. doi : 10.1650 / 0010-5422 (2003) 105 [80: RNGBSW] 2.0.CO; 2 .
    42. ↑ Konter, pp. 113–115. Konter describes in detail the territorial fights between four breeding pairs on a small lake on Fehmarn
    43. ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 36
    44. ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 37
    45. ↑ a b Fjeldså, p. 186
    46. ↑ Valerie Jablow: Bringing Up Baby: Scientists zero in on the caring and cunning ways of a seldom-seen waterbird . In: Smithsonian . 34, No. 1, April 2003, pp. 333-337.
    47. ↑ Ogilvie & Rose (2002), p. 94
    48. ↑ Red-necked Grebe ( Podiceps grisegena ) (PDF; 80 kB) In: "Marshbird" species conservation status assessment . United States Fish and Wildlife Service . Retrieved February 6, 2011.
    49. ↑ Michael L. Chamberlin: Observations on the red-necked grebe nesting in Michigan . (PDF) In: Wilson Bulletin . 89, No. 1, March 1977, pp. 33-46.
    50. ↑ Fjeldså, p. 185
    51. ↑ AGREEMENT ON THE CONSERVATION OF AFRICAN-EURASIAN MIGRATORY WATERBIRDS (AEWA) Annex 2 Waterbird species to which the Agreement applies ( Memento from September 26, 2012 in the Internet Archive )
    52. ↑ Podiceps grisegena in the IUCN Red List of Threatened Species . Retrieved March 4, 2009.
    53. ↑ Bauer et al., P. 188
    54. ^ Colin O'Donnel and Fjeldså: Grebes - Status Survey and Conservation Action Plan , IUCN / SSC Grebe Specialist Group, Gland 1997, ISBN 2-8317-0421-9 , p. 6
    55. ↑ Colin O'Donnel and Fjeldså: Grebes - Status Survey and Conservation Action Plan , IUCN / SSC Grebe Specialist Group, Gland 1997, ISBN 2-8317-0421-9 , p. 24
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    57. ↑ Zhilin MG, Karhu AA: Exploitation of birds in the early Mesolithic of Central Russia. In: Proceedings of the 4th Meeting of the ICAZ Bird Working Group Kraków, Poland, September 11-15, 2001 . (PDF) In: Acta zoologica cracoviensia . 45, 2002, pp. 109-116.
    58. ^ Mannermaa, Kristiina: The archeology of wings: Birds and people in the Baltic Sea region during the Stone Age . In: Academic dissertation . Faculty of Arts at the University of Helsinki. Archived from the original on May 23, 2011. Retrieved February 6, 2011.
    59. ^ Brian Huntley, Rhys E. Green, Yvonne C. Collingham, Stephen G. Willis: A Climatic Atlas of European Breeding Birds , Durham University, The RSPB and Lynx Editions, Barcelona 2007, ISBN 978-84-96553-14-9 , P. 38
    60. ↑ Viktor Wember: The names of the birds in Europe - meaning of the German and scientific names , Aula-Verlag, Wiebelsheim 2007, ISBN 978-3-89104-709-5 , p. 67
    61. ↑ Viktor Wember: The names of the birds in Europe - meaning of the German and scientific names , Aula-Verlag, Wiebelsheim 2007, ISBN 978-3-89104-709-5 , p. 68
    62. ↑ Ogilvie & Rose (2002) 8-9
    63. ↑ Bedetti, C .: Update Middle Pleistocene fossil birds data from Quartaccio quarry (Vitinia, Italy) - The World of Elephants Archived from the original on May 19, 2014. (PDF) In: Proc. 1st intern. Congress - Rome, October 16-20 . 2001, pp. 18-22. Retrieved May 19, 2014.
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