The Heliornithidae are a small

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 ...

of tropical

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s with webbed lobes on their feet like those of

grebe 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 ...

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. The family overall are known as finfoots, although one

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 appropriate s ...

is known as a sungrebe. The family is composed of three species in three genera.

Description

Finfoots resemble

rail Rail or rails may refer to: Rail transport *Rail transport and related matters *Rail (rail transport) or railway lines, the running surface of a railway Arts and media Film * ''Rails'' (film), a 1929 Italian film by Mario Camerini * ''Rail'' ( ...

s; they have long necks, slender bodies, broad tails, and sharp, pointed bills. They have a diverse range of calls, but do not call frequently. Their legs and feet are brightly coloured and, unlike grebes, they are capable of walking well and even moving quickly on land.

Habitat

Finfoots are found in numerous habitats in the tropics as long as there is water and cover. It is uncertain why cover is so essential to finfoots, but they are extremely secretive and often overlooked. Their ranges extend from coastal creeks to fast-moving mountain streams, most commonly being found in large slow-moving bodies of water. They also use swamps, reed beds,

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

s, and forest. Finfoots are territorial, probably for much of the year and certainly when breeding. They are not thought to undertake regular migrations, but some birds do regularly disperse and they are quick to colonise new areas of suitable habitat.

Behaviour

Diet and feeding

Finfoots feed on a wide range of foods,

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s of various sorts being the most frequently observed component of their diet. Little quantitative information on finfoot diet exists, but they have also been recorded eating molluscs,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s, spiders,

frog A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

and some leaves and seeds. Unlike grebes they do not dive to obtain food, instead picking prey off the water's surface or foraging on the shore.

Breeding

All three species tend to breed after the

wet season The wet season (sometimes called the Rainy season) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...

, the exact timing of which is dependent on the local climate. The breeding behaviour of the masked finfoot is almost entirely unknown. All three species exhibit some changes in appearance prior to breeding – masked finfoots develop a fleshy knob above the bill, and the plumage of the male African finfoot and female sungrebe also change. There is considerable variation within the finfoots on several aspects of breeding; in the Sungrebe the nest building and incubation duties are shared between the sexes, in the African finfoot the female alone incubates. The nests of all finfoots are untidy bowls of sticks, twigs, and reeds suspended in vegetation above water.

Species

There are three species. The African finfoot is found in tropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

on streams in woodland. The masked finfoot has a scattered distribution from Eastern India down through southeast

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

to the

Wallace Line The Wallace Line or Wallace's Line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by English biologist Thomas Henry Huxley that separates the biogeographical realms of Asia and Wallacea, a trans ...

. The sungrebe is found in tropical Central and South America. Finfoots are highly secretive and many aspects of their biology are unknown to science.

Gallery

File:African finfoot.jpeg, African finfoot, ''Podica senegalensis'' File:Sungrebe.jpg, Sungrebe, ''Heliornis fulica'' File:Masked Finfoot.JPG, Masked finfoot, ''Heliopais personata''

References

* Bertrand, B. C. R. (1996). "Family Heliornithidae (Finfoots)" in del Hoyo, J., Elliott, A., & Sargatal, J., eds. ''Handbook of the Birds of the World. Vol. 3.'' Lynx Edicions, Barcelona,

External links

Heliornithidae videos
on the Internet Bird Collection * * {{Taxonbar, from=Q661898 Bird families Taxa named by George Robert Gray