Grebes are a widely distributed order of freshwater diving birds, some of which visit the sea when migrating and in winter. This order contains only a single family, the Podicipedidae, containing 22 species in six extant genera.
|Black-necked grebe (Podiceps nigricollis nigricollis), in non-breeding plumage|
Grebes are small to medium-large in size, have lobed toes, and are excellent swimmers and divers. Although they can run for a short distance, they are prone to falling over, since they have their feet placed far back on the body.
Grebes have narrow wings, and some species are reluctant to fly; indeed, two South American species are completely flightless. They respond to danger by diving rather than flying, and are in any case much less wary than ducks. Extant species range in size from the least grebe, at 120 grams (4.3 oz) and 23.5 cm (9.3 inches), to the great grebe, at 1.7 kg (3.8 lbs) and 71 cm (28 inches).
The North American and Eurasian species are all, of necessity, migratory over much or all of their ranges, and those species that winter at sea are also seen regularly in flight. Even the small freshwater pied-billed grebe of North America has occurred as a transatlantic vagrant to Europe on more than 30 occasions.
Bills vary from short and thick to long and pointed, depending on the diet, which ranges from fish to freshwater insects and crustaceans. The feet are always large, with broad lobes on the toes and small webs connecting the front three toes. The hind toe also has a small lobe. Recent experimental work has shown that these lobes work like the hydrofoil blades of a propeller. Curiously, the same mechanism apparently evolved independently in the extinct Cretaceous-age Hesperornithiformes, which are totally unrelated birds.
Grebes have unusual plumage. It is dense and waterproof, and on the underside the feathers are at right-angles to the skin, sticking straight out to begin with and curling at the tip. By pressing their feathers against the body, grebes can adjust their buoyancy. Often, they swim low in the water with just the head and neck exposed. They swim by simultaneously spreading out the feet and bring them inward with the webbing expanded to produce the forward thrust in much the same way as frogs.
In the non-breeding season, grebes are plain-coloured in dark browns and whites. However, most have ornate and distinctive breeding plumages, often developing chestnut markings on the head area, and perform elaborate display rituals. The young, particularly those of the genus Podiceps, are often striped and retain some of their juvenile plumage even after reaching full size. In the breeding season, they mate at freshwater lakes and ponds, but some species spend their non-breeding season along seacoasts.
When preening, grebes eat their own feathers, and feed them to their young. The function of this behaviour is uncertain but it is believed to assist with pellet formation, and to reduce their vulnerability to gastric parasites.
The grebes are a radically distinct group of birds as regards their anatomy. Accordingly, they were at first believed to be related to the loons, which are also foot-propelled diving birds, and both families were once classified together under the order Colymbiformes. However, as recently as the 1930s, this was determined to be an example of convergent evolution by the strong selective forces encountered by unrelated birds sharing the same lifestyle at different times and in different habitat. Grebes and loons are now separately classified orders of Podicipediformes and Gaviiformes, respectively.
The cladistics vs. phenetics debate of the mid-20th century revived scientific interest in generalizing comparisons. As a consequence, the discredited grebe-loon link was discussed again. This even went as far as proposing monophyly for grebes, loons, and the toothed Hesperornithiformes. In retrospect, the scientific value of the debate lies more in providing examples that a cladistic methodology is not incompatible with an overall phenetical scientific doctrine, and that thus, simply because some study "uses cladistics", it does not guarantee superior results.
Molecular studies such as DNA-DNA hybridization (Sibley & Ahlquist, 1990) and sequence analyses fail to resolve the relationships of grebes properly due to insufficient resolution in the former and long-branch attraction in the latter. Still – actually because of this – they do confirm that these birds form a fairly ancient evolutionary lineage (or possibly one that was subject to selective pressures down to the molecular level even), and they support the non-relatedness of loons and grebes.
Recent molecular studies have suggested a relation with flamingos while morphological evidence also strongly supports a relationship between flamingos and grebes. They hold at least eleven morphological traits in common, which are not found in other birds. Many of these characteristics have been previously identified in flamingos, but not in grebes. The fossil Palaelodids can be considered evolutionarily, and ecologically, intermediate between flamingos and grebes.
For the grebe-flamingo clade, the taxon Mirandornithes ("miraculous birds" due to their extreme divergence and apomorphies) has been proposed. Alternatively, they could be placed in one order, with Phoenocopteriformes taking priority.
The fossil record of grebes is incomplete; there are no transitional forms between more conventional birds and the highly derived grebes known from fossils, or at least none that can be placed in the relationships of the group with any certainty. The enigmatic waterbird genus Juncitarsus, however, may be close to a common ancestor of flamingos and grebes.
The Early Cretaceous (Berriasian, around 143 mya) genus Eurolimnornis from NW Romania was initially believed to be a grebe. If it is indeed related to this lineage, it must represent a most basal form, as it almost certainly predates any grebe-flamingo split. On the other hand, the single bone fragment assigned to this taxon is not very diagnostic and may not be of a bird at all.
Telmatornis from the Navesink Formation – also Late Cretaceous – is traditionally allied with the Charadriiformes and/or Gruiformes. However, a cladistic analysis of the forelimb skeleton found it highly similar to the great crested grebe and unlike the painted buttonquail (now known to be a basal charadriiform lineage), the black-necked stilt (a more advanced charadriiform), or the limpkin (a member of the Grui suborder of Gruiformes), namely in that its dorsal condyle of the humerus was not angled at 20°–30° away from long axis of the humerus. The analysis did not result in a phylogenetic pattern but rather grouped some birds with similar wing shapes together while others stood separate. It is thus unknown whether this apparent similarity to grebes represents an evolutionary relationship, or whether Telmatornis simply had a wing similar to that of grebes and moved it like they do.
True grebes suddenly appear in the fossil record in the Late Oligocene or Early Miocene, around 23–25 mya. While there are a few prehistoric genera that are now completely extinct; Thiornis (Late Miocene -? Early Pliocene of Libros, Spain) and Pliolymbus (Late Pliocene of WC USA – Early? Pleistocene of Chapala, Mexico) date from a time when most if not all extant genera were already present. Because grebes are evolutionarily isolated and they only started to appear in the Northern Hemisphere fossil record in the Early Miocene, they are likely to have originated in the Southern Hemisphere.
A few more recent grebe fossils could not be assigned to modern or prehistoric genera:
Living Podicipediformes based on the work by John Boyd.
The Alaotra grebe (Tachybaptus rufolavatus), also known as Delacour's little grebe or rusty grebe, is an extinct grebe that was endemic to Lake Alaotra and surrounding lakes in Madagascar.Atitlán grebe
The Atitlán grebe (Podilymbus gigas), also known as giant grebe, giant pied-billed grebe, or poc, is an extinct water bird, a relative of the pied-billed grebe. It was endemic at the Lago de Atitlán in Guatemala at an altitude of 1700 m asl. It was described in 1929 by Ludlow Griscom based on a specimen collected in 1926 and had been overlooked in the past. American ecologist Anne LaBastille observed the decline of this species over a period of 25 years. It was declared extinct by 1990.Australasian grebe
The Australasian grebe (Tachybaptus novaehollandiae) is a small waterbird common on fresh water lakes and rivers in greater Australia, New Zealand and on nearby Pacific islands. At 25–27 cm (9.8–10.6 in) in length, it is one of the smallest members of the grebe family, along with the least grebe and little grebe.Black-necked grebe
The black-necked grebe (Podiceps nigricollis), known in North America as the eared grebe, 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 subspecies. Its breeding plumage features a distinctive ochre-coloured plumage that 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, Eurasia, and the Americas.
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 crustaceans, molluscs, tadpoles, and small frogs and fish. When moulting at saline lakes, this bird feeds mostly on brine shrimp. 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. 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 6,000 kilometres (3,700 mi) during migration. 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 by the International Union for the Conservation of Nature (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.Clark's grebe
Clark's grebe (Aechmophorus clarkii) is a North American waterbird 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. Intermediates between the two species are known.
This species nests on large inland lakes in western North America and migrates to the Pacific coast over the winter. It maintains local populations year-round in California, Nevada, and Arizona (the Lower Colorado River Valley), as well as in central Mexico.
It feeds by diving for insects, polychaete worms, crustaceans, and salamanders.It performs the same elaborate courtship display as the western grebe.Gloster Grebe
The Gloster Grebe was developed by the Gloster Aircraft Company from the Gloster Grouse (an experimental aircraft later developed as a trainer), and was the Royal Air Force's first post-First World War fighter aircraft, entering service in 1923.Great crested grebe
The great crested grebe (Podiceps cristatus) is a member of the grebe family of water birds noted for its elaborate mating display. Its scientific name comes from Latin: the genus name Podiceps is from podicis, "vent" and pes, "foot", and is a reference to the placement of a grebe's legs towards the rear of its body; the species name, cristatus, means "crested".Hoary-headed grebe
The hoary-headed grebe (Poliocephalus poliocephalus) is a member of the grebe family. It breeds in southern parts of Australia and Tasmania; it winters throughout the island. The bird takes its name from the silvery-white streaking on its black head. It is common in Australia, with a population of about 500,000. Its habitat is similar to that of the Australasian grebe.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 Eurasia, and P. a. cornutus, which breeds in North America. The Eurasian subspecies is distributed over most of northern Europe and Asia, breeding from Greenland to western China. The North American subspecies spans most of Canada and some of the United States. The species got its name from large patches of yellowish feathers located behind the eyes, called "horns", that the birds can raise and lower at will.Least grebe
The least grebe (Tachybaptus dominicus), an aquatic bird, is the smallest member of the grebe family. It occurs in the New World from the southwestern United States and Mexico to Chile and Argentina, and also on Trinidad and Tobago, the Bahamas and the Greater Antilles.Little grebe
The little grebe (Tachybaptus ruficollis), also known as dabchick, is a member of the grebe family of water birds. The genus name is from Ancient Greek takhus "fast" and bapto "to sink under". The specific ruficollis is from Latin rufus "red" and Modern Latin -collis, "-necked", itself derived from Latin collum "neck".At 23 to 29 cm (9.1 to 11.4 in) in length it is the smallest European member of its family. It is commonly found in open bodies of water across most of its range.New Zealand grebe
The New Zealand grebe, New Zealand dabchick, or weweia (Poliocephalus rufopectus) is a member of the grebe family endemic to New Zealand.Outline of birds
The following outline is provided as an overview of and topical guide to birds:
Birds (class Aves) – winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most varied of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich.Pied-billed grebe
The pied-billed grebe (Podilymbus podiceps) is a species of the grebe family of water birds. Since the Atitlán grebe (Podilymbus gigas) has become extinct, it is the sole extant member of the genus Podilymbus. The pied-billed grebe is primarily found in ponds throughout the Americas. Other names of this grebe include American dabchick, rail, dabchick, Carolina grebe, devil-diver, dive-dapper, dipper, hell-diver, pied-billed dabchick, pied-bill, thick-billed grebe, and water witch.Red-necked grebe
The red-necked grebe (Podiceps grisegena) is a migratory aquatic 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. Grebes 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 of its two subspecies—P. g. grisegena found in Europe and western Asia, and the larger P. g. holboelii (formerly Holbœll grebe), in North America and eastern Siberia—is evaluated as Least Concern, and the global population is stable or growing.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 4,000 metres (13,000 ft). Its natural habitat is freshwater lakes but it also feeds in saline lakes.Titicaca grebe
"Centropelma" redirects here. This was also the initial, preoccupied name of the spider genus Nicodamus.
The Titicaca grebe (Rollandia microptera), also known as the Titicaca flightless grebe or short-winged grebe, is a grebe found on the altiplano of Peru and Bolivia. As its name implies, its main population occurs on Lake Titicaca. Lake Uru Uru and Poopó, the Rio Desaguadero, and small lakes that connect to Lake Titicaca in wet years, serve as "spillovers" territory. In the past, the population was larger and several of these lakes – such as Lakes Umayo and Arapa – apparently had and may still have permanent large colonies (BirdLife International 2006). It is sometimes placed in Podiceps or a monotypic genus Centropelma. Its local name is zampullín del Titicaca.USS Grebe (AM-43)
USS Grebe (AM-43) was a Lapwing-class minesweeper in the United States Navy.
Grebe was built by the Staten Island Steam Boat Co., was launched 17 December 1918; it was sponsored by Miss Emma Youmans and commissioned at the Brooklyn Navy Yard 1 May 1919; Lt. Niels Drustrup was in command. It served in many capacities until it was destroyed by a hurricane in 1943.Western grebe
The western grebe (Aechmophorus occidentalis) is a species in the grebe family of water birds. Folk names include "dabchick", "swan grebe" and "swan-necked grebe".
Western grebe fossils from the Late Pleistocene of SW North America were described as a distinct species, but later ranked as a paleosubspecies Aechmophorus occidentalis lucasi. More recent study found them to fall within the variation now known to exist in today's birds.