Great crested grebes are residents of Western Europe, Britain, and Ireland, parts of southern and eastern Africa, Australia, and New Zealand. Breeding populations are found from Eastern Europe through Southern Russia and to Mongolia. After migration, wintering populations can be found on the coastal waters of Europe, southern Africa, and Australia, as well as in bodies of water throughout southern Asia. The estimated global population is 920,000 to 1,400,000. (BirdLife International, 2013; Hughes, 1982)
Great crested grebes can be found in a variety of aquatic habitats, including lakes, artificial bodies of water, slow flowing rivers, swamps, bays, and lagoons. Breeding habitats consist of shallow open bodies of fresh or brackish water. There must also be vegetation on the banks and in the water in order to provide suitable locations for nests. In the winter, individuals from some populations migrate to bodies of water that are located in mild climates. (Hughes, 1982; Simmons, 1974)
Great crested grebes are the largest grebes in Europe. The plumage on the back and sides is mottled brown. The back of the neck is dark brown and the front of the neck and underside are white. They have long necks and reddish-orange plumes with black tips on their heads. These plumes are only present during the breeding season, they start to develop in the winter and are fully developed by spring. They also have erectile black crests on the crown of the head that are present year round. They have short tails and legs set far back for efficient swimming and diving. Males and females look similar and juvenile birds have black stripes on their cheeks. (Huxley, 1968)
Once populations arrive on breeding grounds, courtship displays begin and pair bonds form. Pair bonds are usually seasonal, although some pairs have been seen overwintering together. Great crested grebes have an elaborate courtship display. It begins with the male and female facing each other, necks held up straight, showing the whites of their necks. Their ears are vertical, the crest is erected, and the tail is cocked. They both shake their heads from side-to-side, alternating between fast and slow. Between shaking bouts, a preening-like behavior occurs, and then more shaking with wing lifts. Sometimes this display incorporates an outward wing display, in which the tops of the wings are brought forward and the crest is erected. A diving behavior is sometimes incorporated into the display, and occasionally, one bird offers an aquatic weed to the other. Another notable courtship behavior is the advertising behavior, which has only been observed being performed by the female. It consists of a loud, metallic sounding note followed by a quieter purr-like sound. They make this sound with the neck elongated, the lower neck thickened, and the crest flattened. They do not move very much while making this call. The purpose of this behavior is either to attract a mate or to reform an existing pair bond. After pair bonds are formed, pairs look for nest sites together and continue to perform courtship behaviors. Copulatory behavior, such mounting one another, may be performed far before egg laying, and thus does not lead to fertilization. Many nests may also be built, possibly as a form of courtship behavior, before the final one is used to lay eggs. When this nest is chosen, courtship behaviors cease and true copulation, resulting in fertilization, occurs. (Huxley, 1968; Simmons, 1954; Simmons, 1974)
Great crested grebes breed once individuals arrive at breeding territories. Pairs can begin forming as early as January. Once on the breeding grounds, they are opportunistic breeders and begin their breeding efforts only once conditions are appropriate. The most important factor that determines the start of breeding is the amount of covered habitat available to build protected nests. Other factors, such as weather, water level, and food supply also determine when breeding begins. For example, if water levels are higher, more of the surrounding vegetation will become flooded. This provides more cover for protected nests. Warmer temperatures and abundant food can also cause breeding to start earlier. Nests are made of aquatic weeds, reeds, thickets, and kelp fronds. These materials are woven into existing water plants. The nests are suspended in the water, which protects the clutch from terrestrial predators. They are built in a few hours and are built equally by the male and the female. The "true nest," where the eggs are laid, rises out of the water, and is distinct from the two surrounding platforms, one of which may be for copulating and the other for resting during incubation and brooding. Nests need to be accessible from water because grebes are aquatic specialists and cannot travel across land. Nest size is variable; for example, larger nests are built in the Baltic Sea than in nearby lakes. Clutches range from 1 to 9 eggs, but average between 3 and 4 eggs. Incubation lasts 27 to 29 days and both males and females incubate equally. Incubation begins after the first egg is laid, which makes embryo development and hatching asynchronous. This causes a sibling hierarchy once the chicks hatch. The nest is abandoned once the last chick has hatched and sometimes viable eggs are abandoned. Brood sizes are usually 1 to 4 chicks. This number differs from clutch size because of sibling competition, bad weather, or egg desertion. There is usually only a single brood, although some pairs double brood, and up to 5 nesting attempts may be made if nests are unsuccessful. Young fledge at 71 to 79 days. (Hughes, 1982; Huxley, 1968; Simmons, 1974; Ulfvens, 1988)
Parents both incubate eggs and brood and care for their young. Once the chicks leave the nest, the parents take turns carrying young on their back out into the water for up to 3 weeks. The parents still guard the chicks in the 4th week. After the chicks get bigger, the brood divides, and the male and female both choose chicks, which they solely feed and look after. This forms two family sub-groups, which no longer associate and are sometime hostile toward each other. Within the sub-group, there is one chick favored by the parent, who gets fed more often. The chicks stay with their parents for 11 to 16 weeks. (Simmons, 1974)
There are no data on the average lifespan or longevity of great crested grebes. The oldest known bird was at least 11 years, 10 months, and 5 days old. It was banded as an adult in Britain and found again shortly after death. (Robinson and Clark, 2012)
Individuals are not territorial in the winter months and most birds are solitary. During the breeding season, pairs are formed and there is usually little association between different pairs. Occasionally, loose colonies are formed, consisting of multiple pairs. Colonies are more likely to be formed if there is a shortage of suitable nesting habitat or if prime nesting habitat is clumped. Breeding pairs defend nest sites. The size of the territory itself is highly variable among pairs and populations. The male and female in the pair both defend their mate, nest, and young. Frequent fights were observed at one breeding ground in Britain over territorial boundaries during the breeding season. Territory defense ceases once breeding is finished. Great crested grebes exhibit an interesting feather eating behavior. They ingest their feathers more frequently when their diet is low in indigestible matter, this is thought to be a way to create pellets that can be ejected in order to decrease the occurrence of parasites in the gastric system. Great crested grebes are mainly diving birds and prefer to dive and swim rather than fly. (McCartan and Simmons, 1956; Piersma and Van Eerden, 1989; Stanevičius and Švažas, 2005)
Home range size of great crested grebes is not reported in the literature.
Great crested grebes communicate mainly with visual and acoustic cues. They detect prey in the water using visual cues. Mating pairs communicate by producing calls, such as during their advertising behavior. They also perform elaborate courtship displays, which consist mainly of visual cues. Other than communication between pairs, great crested grebes are solitary. Nothing specific is known about olfaction in great crested grebes, but other species of grebes have relatively large olfactory bulbs, which indicates that they may use olfaction for uses such as finding prey. There is also evidence that great crested grebes have a sense of taste. One great crested grebe rejected a fish that was later found to have epidermal infection. Video recording showed that the grebe held the fish in the front of its beak before rejecting it, as opposed to the middle of its beak, which is where grebes hold healthy fish. The front part of the beak used for rejection was later found to contain taste buds, which suggests that taste was the mechanism for rejection. Also, because they are a migratory species, great crested grebes may use magnetic cues to map their routes. (Berkhoudt, 1985; Clowater, 1993; Huxley, 1968; Piersma, et al., 1988)
The diet of great crested grebes consists mainly of large fish, but also includes insects, crustaceans, molluscs, adult and larval amphibians, and invertebrate larvae. Their favored foods include roach (Rutilus rutilus), perch (Perca fluviatilis), and smelt (Osmerus eperlanus). Great crested grebes catch their prey by diving under the surface of the water. They forage the most during dawn and dusk, possibly because this is when their prey are closest to the surface. This makes the fish easier to detect visually and also reduces diving distance. (BirdLife International, 2013; Piersma, et al., 1988; Simmons, 1974)
Parents perform an interesting egg-covering behavior in which they cover the eggs with nest material before leaving the nest. This behavior has been found to effectively protect against their main predators, Eurasian coots (Fulica atra), which prey on eggs. When the nest is disturbed, the parent covers the eggs, dives into the water, and resurfaces in a location farther away from the nest. Another anti-predator behavior that great crested grebes share with all grebes is the building of nests that are fully or partially suspended in water, which protects the eggs from any terrestrial predators. There is no information in the literature about specific predators of juvenile or adult great crested grebes. However, chicks of another grebe species, western grebes (Aechmophorus occidentalis), are preyed on by fish such as bass species (Micropterus) and pike species (Esox). To avoid juvenile predation, adults carry chicks on their backs for up to 3 weeks after hatching. (Keller, 1989; Ulfvens, 1988)
Great crested grebes are predators to large fish, such as roaches (Rutilus rutilus) and perch (Perca fluviatilis), small fish, such as smelt (Osmerus eperlanus), insects, crustaceans, molluscs, adult and larval amphibians, and invertebrate larvae. (BirdLife International, 2013; Piersma, et al., 1988; Simmons, 1974)
Great crested grebes were hunted for food in New Zealand. Their breast plumage and head plumes were also used for decoration on clothing during Victorian times in Britain. This, however, greatly threatened the species and a group of women formed the ‘Fur, Fin and Feather Folk’ in 1889 who were against killing birds for clothing. (Arkive, 2013; BirdLife International, 2013)
Some fish farmers complain that great crested grebes eat too many fish and cause economic losses. However, a study showed that grebe feeding only affected fish populations marginally. (Ulenaers and Van Vessem, 1994)
Great crested grebes were historically hunted for food in New Zealand and for plumage in Britain. They are no longer threatened by hunting, but may be threatened by human impacts including modification of lakes, urban development, introduced competitors, introduced predators, fishing nets, oil spills, and avian influenza. However, they currently have a conservation status of least concern according to the IUCN. (Arkive, 2013; BirdLife International, 2013)
Sydney Hope (author), The College of New Jersey, Keith Pecor (editor), The College of New Jersey, Tanya Dewey (editor), University of Michigan-Ann Arbor.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
areas with salty water, usually in coastal marshes and estuaries.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.
parental care is carried out by females
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
mainly lives in water that is not salty.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
makes seasonal movements between breeding and wintering grounds
eats mollusks, members of Phylum Mollusca
Having one mate at a time.
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
an animal that mainly eats fish
mainly lives in oceans, seas, or other bodies of salt water.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
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Berkhoudt, H. 1985. Structure and function of avian taste receptors. Pp. 463/496 in A King, J McLelland, eds. Form and Function in Birds. London: Academic Press.
BirdLife International, 2013. "Species factsheet: Podiceps cristatus" (On-line). BirdLife International. Accessed November 13, 2013 at http://www.birdlife.org.
Clowater, J. 1993. Distribution and Foraging Behavior of Wintering Western Grebes. Doctoral dissertation.
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Keller, V. 1989. Egg-covering behaviour by great crested grebes Podiceps cristatus. Ornis Scandinavica, 20: 129-131.
McCartan, L., K. Simmons. 1956. Territory in the great crested grebe Podiceps cristatus re-examined. The Ibis, 98: 370-378.
O'Donnel, C., J. Fjeldsa. 1997. "Grebes - Status Survey and Conservation Action Plan. IUCN/SSC Grebe Specialist Group" (On-line pdf). Accessed November 19, 2013 at http://www.wetlands.org/LinkClick.aspx?fileticket=TncDRa5p40I%3D&tabid=192&mid=6917.
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Stanevičius, V., S. Švažas. 2005. Colonial and associated with coot (Fulica atra) nesting in great crested grebe (Podiceps cristatus): comparison of three lakes. Acta Zoologica Lituanica, 15: 324-329.
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Ulfvens, J. 1988. Nest characteristics and nest survival in the horned grebe Podiceps auritus and great crested grebe Podiceps cristatus in a Finnish archipelago. Annales Zoologici Fennici, 25: 293-298.