Grebes are aquatic diving birds in the order Podicipediformes. Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably in stable lakes. The order contains a single family, the Podicipedidae, which includes 22 species in six extant genera. Although, superficially, they resemble other diving birds such as loons and coots, they are most closely related to flamingos, as supported by morphological, molecular and paleontological data. Many species are monogamous and are known for their courtship displays, with the pair performing synchronized dances across the water's surface. The birds build floating vegetative nests where they lay several eggs. About a third of the world's grebes are listed at various levels of conservation concerns—the biggest threats including habitat loss, the introduction of invasive predatory fish and human poaching. As such, three species have gone extinct.
The horned grebe or Slavonian grebe is a relatively small waterbird in the family Podicipedidae. There are two known subspecies: P. a. auritus, which breeds in the Palearctic, and P. a. cornutus, which breeds in North America. The Eurasian subspecies is distributed over most of northern Europe and the Palearctic, 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.
The pied-billed grebe is a species of the grebe family of water birds. Because the Atitlán grebe has become extinct, the Pied-Billed Grebe is now 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.
Moorhens—sometimes called marsh hens—are medium-sized water birds that are members of the rail family (Rallidae). Most species are placed in the genus Gallinula, Latin for "little hen". They are close relatives of coots. They are often referred to as (black) gallinules. Recently, one of the species of Gallinula was found to have enough differences to form a new genus Paragallinula with the only species being the lesser moorhen.
Paraptenodytes brodkorbi is a proposed, but possibly invalid, species of extinct penguin in the genus Paraptenodytes. The bird was probably about the size of a king penguin. Known material is limited to a single humerus, Early Miocene in age, found in the Monte León Formation near Puerto San Julián in Santa Cruz Province, Argentina. It exists as an unnumbered specimen in the collection of the Museo Argentino de Ciencias Naturales.
Centuriavis is an extinct genus of phasianid landfowl from the Miocene of Nebraska. Known from a well preserved and articulated skeleton preserving the skull as well as much of the vertebral column, its name stems from the fact that it remained undescribed for nearly a hundred years. It is estimated that it weighed 1.7 kg (3.7 lb), which would make it comparable in size with the average female greater sage grouse. Centuriavis may be related to grouse and turkeys and only a single species has been described: Centuriavis lioae.
Miobaptus is a fossil genus of grebe that is known from several specimens collected from Czechia and Lake Baikal dating from the Early Miocene to Middle Miocene. Considered to be one of the most primitive genus of grebes, the anatomy of Miobaptus suggests it was less adapted for the aquatic mode of life than modern grebes, but had better flight maneuverablity.
Miodytes is a fossil genus of grebe known from a nearly complete specimen from Valjevo Basin, western Serbia known from an almost complete right wing skeleton. It contains a single species, M. serbicus.
Pliolymbus is a fossil genus of grebe known from the Late Pliocene to Early Pleistocene of United States and Mexico. It is known from a single species, P. baryosteus.
Podilymbus majusculus is an extinct species of grebe recovered from the Piacenzian age of the United States.
Podilymbus wetmorei is an extinct species of grebe recovered from the Late Pleistocene age of the United States.
Podicipedini is a tribe of waterbirds belonging to the family Podicipedidae containing the genera Aechmophorus and Podiceps. Members of this tribe of grebes are characterized based on the presence of nuptial plumes and downy young with a bare crown patch. They are more specialized for diving though the anatomy that enables them to do so makes them weaker to stand upright. Further they have much complex mating dance rituals. Based on these characteristics, other possible genera in the clade include Poliocephalus and Rollandia. Indeed a molecular phylogeny by Ogawa et al. (2015) using genetic data from 3 mitochondrial markers found Podiceps to be paraphyletic in respect to Rollandia, as the latter genus is more closely related to several New World species of the former genus. The inclusion of the Neogene genera of Pliolymbus and Thiornis is based on their possible reclassification as junior synonyms as Podiceps.
Podiceps oligoceanus is an extinct species of grebe possibly from the Neogene period which the specimen has been found in the United States.
Podiceps dixi is a possible extinct species of grebe from the United States.
Podiceps howardae is a possible extinct species of grebe from the United States, possibly a larger and earlier form of the horned grebe.
Podiceps solidus is an extinct small species of Upper Miocene to Lower Pliocene grebe from Western Mongolia.
Podilymbini is a potential tribe of waterbirds belonging to the family Podicipedidae containing the genus Podilymbus and Tachybaptus. In comparison to Podicipedini, podilymbins are characterized by the lack of nuptial plumes and the chicks have rufous down in one or more patches on the crown. They are able to stand upright and move around land more so. The mating displays among these birds are simpler.
Podiceps discors is an extinct species of grebe from the Upper Pliocene of western North America. It was similar to the black-necked grebe.
Podiceps arndti is an extinct species of grebe from the Upper Pliocene of California.
