HOME

TheInfoList



OR:

Grebes () are aquatic diving birds in the
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
Podicipediformes . Grebes are widely distributed
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does incl ...
birds, with some species also found in
marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military ...
habitats during migration and winter. Some flightless species exist as well, most notably in stable lakes. The order contains a single
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
, the Podicipedidae, which includes 22
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
in six extant
genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
. Although, superficially, they resemble other diving birds such as
loon Loons ( North American English) or divers ( British / Irish English) are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family Gaviidae and order ...
s and
coot Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usually ...
s, they are most closely related to flamingos, as supported by morphological, molecular and paleontological data. Many species are
monogamous Monogamy ( ) is a form of dyadic relationship in which an individual has only one partner during their lifetime. Alternately, only one partner at any one time ( serial monogamy) — as compared to the various forms of non-monogamy (e.g., pol ...
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.


Field characteristics

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 America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...
n species are completely flightless. They respond to danger by diving rather than flying, and are in any case much less wary than
duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form ...
s. Extant species range in size from the least grebe, at 120 g (4.3 oz) and 23.5 cm (9.3 in), to the great grebe, at 1.7 kg (3.8 lbs) and 71 cm (28 in). Bills vary from short and thick to long and pointed depending on the diet. 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 A hydrofoil is a lifting surface, or foil, that operates in water. They are similar in appearance and purpose to aerofoils used by aeroplanes. Boats that use hydrofoil technology are also simply termed hydrofoils. As a hydrofoil craft gains s ...
blades of a propeller. Grebes have unusual
plumage Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
. 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 Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the ...
. Often, they swim low in the water with just the head and neck exposed. They swim by simultaneously spreading out the feet and bringing them inward, with the webbing expanded to produce the forward thrust in much the same way as frogs. In the nonbreeding 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 ''Podiceps'' is a genus of birds in the grebe family. The genus name comes from Latin ''podicis'', "rear-end" and ''ped'', "foot", and is a reference to the placement of a grebe's legs towards the rear of its body. It has representatives bree ...
'', are often striped and retain some of their juvenile plumage even after reaching full size. 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
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
s.


Systematics

The grebes are a radically distinct group of birds as regards their
anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...
. Accordingly, they were at first believed to be related to the
loon Loons ( North American English) or divers ( British / Irish English) are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family Gaviidae and order ...
s, which are also foot-propelled diving birds, and both families were once classified together under the order
Colymbiformes Colymbiformes is a disused order of birds that was once used to classify grebes and loons. Scientific study has revealed that these two types of waterbirds are not so closely related; they have been reclassified in the orders '' Podicipediformes'' ...
. However, as early as the 1930s, this was determined to be an example of
convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
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. 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. One clade of fossil stem-flamingos the palaelodids can be considered evolutionarily, and ecologically, intermediate between flamingos and grebes. For the grebe-flamingo
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...
, the
taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...
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.


Fossil grebes

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 Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
'' Juncitarsus'', however, may be close to a common ancestor of flamingos and grebes. The
Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145& ...
(
Berriasian In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ag ...
, around 143 mya) genus '' Eurolimnornis'' from NW
Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...
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 ''Telmatornis'' is a valid prehistoric bird genus of unclear affiliations. It apparently lived in the Late Cretaceous; its remains were found in the early Maastrichtian (c.71-68 million years ago) Navesink Formation of New Jersey. A single speci ...
'' from the
Navesink Formation The Navesink Formation is a 66 to 70 mya greensand glauconitic marl and sand geological formation in New Jersey. It is known for its Cretaceous period fossil shell beds and dinosaur bones. Description The Navesink Formation, named after Navesi ...
– also Late Cretaceous – is traditionally allied with the
Charadriiformes Charadriiformes (, from ''Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water a ...
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 The painted buttonquail (''Turnix varius'') is a species of buttonquail, the family Turnicidae, which resemble, but are unrelated to, the quails of Phasianidae. This species is resident in Australia where numbers are believed to be in decline. A ...
(now known to be a basal charadriiform lineage), the
black-necked stilt The black-necked stilt (''Himantopus mexicanus'') is a locally abundant shorebird of American wetlands and coastlines. It is found from the coastal areas of California through much of the interior western United States and along the Gulf of Mexic ...
(a more advanced charadriiform), or the limpkin (a member of the Grui
suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
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 humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a r ...
. The analysis did not result in a
phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...
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 The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...
or Early
Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
, around 23–25 mya. While there are a few prehistoric genera that are now completely extinct; ''
Thiornis ''Thiornis'' is a fossil genus of Middle Miocene grebe known from a nearly complete specimen from Libros, Spain. Originally classified as a type of moorhen, ''Thiornis'' has since been classified as a species of grebe. The overall anatomy of th ...
'' (Late Miocene –? Early Pliocene of Libros, Spain) and ''
Pliolymbus ''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''. History The specimens were collected in the summer of 1950 from Kans ...
'' (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. * Genus †''
Miobaptus ''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 ''Mi ...
'' Švec, 1982 ** †'' Miobaptus huzhiricus'' Zelenkov, 2015 ** †'' Miobaptus walteri'' Švec, 1982 'Podiceps walteri'' (Švec, 1984) Mlíkovský, 2000* Genus †''
Miodytes ''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''. History The specimen was collect ...
'' Dimitreijevich, Gál & Kessler, 2002 ** †'' Miodytes serbicus'' Dimitreijevich, Gál & Kessler, 2002 * Genus †''
Pliolymbus ''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''. History The specimens were collected in the summer of 1950 from Kans ...
'' Murray, 1967 'Piliolymbus'' (sic)** †'' Pliolymbus baryosteus'' Murray, 1967 * Genus †''
Thiornis ''Thiornis'' is a fossil genus of Middle Miocene grebe known from a nearly complete specimen from Libros, Spain. Originally classified as a type of moorhen, ''Thiornis'' has since been classified as a species of grebe. The overall anatomy of th ...
'' Navás, 1922 ** †'' Thiornis sociata'' Navás, 1922 'Podiceps sociatus'' (Navás, 1922) Olson, 1995 A few more recent grebe fossils could not be assigned to modern or prehistoric genera: *Podicipedidae gen. et sp. indet. (San Diego Late Pliocene of California) – formerly included in ''Podiceps parvus'' *Podicipedidae gen. et sp. indet. UMMP 49592, 52261, 51848, 52276, KUVP 4484 (Late Pliocene of WC USA) *Podicipedidae gen. et sp. indet. (Glenns Ferry Late Pliocene/Early Pleistocene of Idaho, USA)


Phylogeny

To date there is no complete phylogeny of grebes based on molecular work. However there are comprehensive morphological work from Fjeldså (2004) and Ksepka et al. (2013) that has been done on the grebe genera. Fjeldså (2004) Ksepka et al. (2013)


Recent species listing

Compiled from the following websites: Extinct species assignment follows the Mikko's Phylogeny Archive and Paleofile.com websites. and subspecies names from '' English Names of Birds''.


Natural history


Habitat, distribution and migration

Grebes are a nearly cosmopolitan clade of waterbirds, found on every continent except
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...
. They are absent from the
Arctic circle The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle. The Arctic Circle marks the southernmost latitude at ...
and arid environments. They have successfully colonized and radiated into islands such as
Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...
and
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
. Some species such as the eared grebe (''Podiceps nigricollis'') and great crested grebe (''P. cristatus'') are found in multiple continents with regional subspecies or populations. A few species like the Junin grebe (''P. taczanowskii'') and the recently extinct Atitlan grebe (''Podilymbus gigas'') are lake endemics. During the warmer or breeding seasons, many species of grebes in the northern hemisphere reside in a variety of
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does incl ...
habitats like
lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s and
marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found ...
es. Once winter arrives many will migrate to marine environments usually along the coastlines. The species is most prevalent in the
New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...
with almost half of the world's species living in this part of the world.


Feeding ecology

The feeding ecology of grebes is diverse within the group. Larger species such as those in the genus ''
Aechmophorus ''Aechmophorus''Etymology: ''Aechmophorus'', "spear-bearer", from Ancient Greek ''aichme'' (a spear) + ''phoros'' (one who bears something around), in reference to its bill. is a genus of birds in the grebe family. Species It has two living re ...
'' have spear-like bills to catch mid-depth fish while smaller species such as those in the genera '' Tachybaptus'' and ''
Podilymbus ''Podilymbus'' is a genus of birds in the Grebe family, the genus name is derived from Latin ''Podilymbus'', a contraction of ''podicipes'' ("feet at the buttocks", from ''podici-'', "rump-" + ''pes'', "foot")—the origin of the name of the g ...
'' tend to be short and stout with a preference for catching small aquatic invertebrates. There are much more species of grebes that predate on aquatic invertebrates, with only a handful of large-bodied piscivores. The aforementioned ''Aechmophorus''is the most piscivorous of the grebes. Closely related species that overlap in their often avoid interspecific competition by having prey preferences and adaptations for it. In areas where there is just as a single species, they tend to have more generalized bill with more open preferences to different prey sources.


Breeding and reproduction

Grebes are perhaps best known for their elaborate courtship displays. Most species perform a duet together and many have their own synchronized rituals. Some like those species in the genus ''
Podiceps ''Podiceps'' is a genus of birds in the grebe family. The genus name comes from Latin ''podicis'', "rear-end" and ''ped'', "foot", and is a reference to the placement of a grebe's legs towards the rear of its body. It has representatives bree ...
'' do the iconic "penguin dance" where the male and female stand upright, breast posturing out and run along the water's surface. A similar ritual in other species is the "weed dance" in which both partners hold pieces of aquatic vegetation in their bills and positioned upright towards each other. Similarily there is the "weed rush" in which partners would swim towards each other, necks stretched out with weeds in their bill, and just before colliding do posture themselves upright and then swim in parallel. In the smaller and basal genera like ''Tachybaptus'' and ''Podilymbus'' there is some form of incorporation of aquatic vegetation in their courtship, but it is not as elaborate as the more derived and larger species. It has been hypothesized that such courtship displays between mates originated from intraspecific aggression that evolved in a way it strengthen pair bonds. Once these courtship rituals are completed, both partners would solicit copulation towards each other and would mount on these floating platforms of vegetation. Sometimes they become nests, although often they build a more well structured platform. Females lay two to seven eggs and incubation can last nearly a month. Chicks of the nest hatch asynchronously and once the whole nest has hatched, do the chicks begin to climb on one of their parent's backs. Both parents take care of rearing their young, and the duration of care is longer than those of waterfowl. This enables a greater success rate of survival for the chicks. One parent would dive while the other would watch the young on the surface.


Conservation

Thirty percent of the total extant species are considered to be threaten species by the IUCN. The handful of critically endangered and extinct species of grebe are those of lake endemics and nearly all of them are or were flightless. The extinct species consists of the Alaotra grebe (''Tachybaptus rufolavatus''), the Atitlán grebe, and the Colombian grebe (''Podiceps andinus''). These species went extinct due to anthropogenic changes, such as habitat loss, the introduction of invasive predatory fishes, and the usage of fishing nets that tangled birds in the lakes they once existed in. These are the same issues along with climate change that are happening to the Colombian grebe's closest relatives, the Junin grebe and hooded grebe (''Po. gallardoi'').


See also

*
List of Podicipediformes by population This is a list of Podicipediformes species by global population. While numbers are estimates, they have been made by the experts in their fields. For more information on how these estimates were ascertained, see Wikipedia's articles on population ...


References


Further reading

*Konter, André (2001): ''Grebes of our world: visiting all species on 5 continents''. Lynx Edicions, Barcelona. * Ogilvie, Malcolm & Rose, Chris (2003): ''Grebes of the World''. Bruce Coleman Books, Uxbridge, England. * Sibley, Charles Gald & Monroe, Burt L. Jr. (1990): ''Distribution and taxonomy of the birds of the world: A Study in Molecular Evolution''. Yale University Press, New Haven, CT.


External links


Grebe videos and photos
on the Internet Bird Collection
Tree of Life Grebes
*openclipart.org
Grebes clip-art''Diving Birds of North America''
by Paul Johnsgard
Grebes Walk on Water
Documentary produced by
Oregon Field Guide ''Oregon Field Guide'' is a weekly television program produced by Oregon Public Broadcasting focusing on recreation, the outdoors, and environmental issues in the state of Oregon. The show has become part of the Oregon zeitgeist. Steve Amen i ...

Grebe Vocalization - The Songs of The Grebes
* {{Authority control Podicipedidae Podicipediformes Diving animals Extant Chattian first appearances Taxa named by Charles Lucien Bonaparte