Red-necked grebe

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Red-necked Grebe
Podiceps-grisegena-008.jpg
Scientific classification
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P. grisegena
Binomial name
Podiceps grisegena
(Boddaert, 1783)

The Red-necked Grebe, Podiceps grisegena, is a member of the grebe family of water birds.

Description

These grebes range from 43 to 58 cm (17 to 23 inches) long and weigh from 750 to 1620 grams (1.6 to 3.6 lbs), with a 60 cm (24 inch) average wingspan. In summertime, adults are unmistakable due to their red neck and white throat. In winter, the Red-necked Grebe is duskier than most grebes, with no white above the eye, and a thick, yellowish bill. It is a somewhat large grebe, about the same size as an average duck, but is smaller than the Great Crested Grebe in Eurasia and the Western Grebe and Clark's Grebe in North America.

The American and East Siberian race holboelii (Holboell's Grebe, named for Danish zoologist Carl Peter Holböll) differs slightly from the nominate European race grisegena in adult plumage, when it has more extensive yellow on its bill. In holboellii the yellow extends almost to the end of the lower mandible, whereas on grisegena the yellow is much more restricted. This difference only applies to adult birds however; juvenile and first-winter grisegena can have extensive yellow bills.

Distribution and habitat

It breeds in areas of freshwater lakes across Europe, western Asia and northwestern North America. Most birds migrate in winter to the coast. In North America and eastern Asia, this grebe is almost fully dependent on bogs and lakes in taiga or boreal forests. In Europe and western Asia, birds often nest in taiga, but will inhabit more altered habitats, including manmade fish ponds.

Behaviour

It has an elaborate mating display. Like all grebes, it nests on the water's edge, since its legs are set very far back and it cannot walk well. Usually it lays 4 to 5 eggs (sometimes anywhere from 1 to 9 are reported) at the end of April, shortly after the last of ice break-ups in the north. Eggs average 35.3 mm (1.4 inches) in breath, 54.5 mm (2.1 inches) long, and weigh about 38.2 grams (1.3 oz). Pairs may renest up to 5 times if a nest fails. The mean incubation period is probably 28 days, but has been reported from 21 to 35 days. The young are often carried on the back of their parents from up to 17 days. The young can fly at 7 to 9 weeks, but are often separated from their parents before that, and leave the nesting body of water at about 9 to 10 weeks.

This grebe is an excellent swimmer and diver. Most of the diet is comprised by small fish, but locally aquatic insects can be very important prey for grebes of all ages. Crustaceans can also be major prey, comprising up to 20% of their prey. It takes a long-running "taxi" in order for this small-legged and small-winged birds to take off, so they rarely fly outside of migration. Predators of adults are Peregrine Falcons, owls, especially Great Horned Owls in North America and, while nesting, mink and eagles. Predators of nests and nestlings include Common Ravens, crows, gulls, coots, large aquatic rodents, raccoons, bass and pike.

The Red-necked Grebe is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. It is thought that this species is susceptible to large concentrations of pollutants, especially mercury. Since hunting, oil spills and fishing net accidents are only local problems, the main threat to this species is habitat loss, which is an increasingly widespread issue.


Gallery

References

  • BirdLife International (2004). "Podiceps grisegena". IUCN Red List of Threatened Species. Version 2006. International Union for Conservation of Nature. Retrieved 12 May 2006.CS1 maint: uses authors parameter (link) Database entry includes justification for why this species is of least concern
  • Olgilvie and Rose, Grebes of the World ISBN 1-872842-03-8

External links

External links