八色鸫科科

Pittas are a family, Pittidae, of passerine birds found in Asia, Australasia and Africa. There are 46 species of pittas, all similar in general appearance and habits. The pittas are suboscines from the Old World, and their closest relatives among other birds are in the genera Smithornis and Calyptomena. Initially placed in a single genus, as of 2009 they have been split into three genera: Pitta, Erythropitta and Hydrornis. Pittas are medium-sized by passerine standards, at 15 to 25 cm (6–10 in) in length, and stocky, with strong, longish legs and long feet. They have very short tails and stout, slightly decurved bills. Many have brightly coloured plumage.

Most pitta species are tropical; a few species can be found in temperate climates. They are mostly found in forests, but some live in scrub and mangroves. They are highly terrestrial and mostly solitary, and usually forage on wet forest floors in areas with good ground cover. They eat earthworms, snails, insects and similar invertebrate prey, as well as small vertebrates. Pittas are monogamous and females lay up to six eggs in a large domed nest in a tree or shrub, or sometimes on the ground. Both parents care for the young. Four species of pittas are fully migratory, and several more are partially so, though their migrations are poorly understood.

Four species of pitta are listed as endangered by the International Union for Conservation of Nature; a further nine species are listed as vulnerable and several more are near-threatened. The main threat to pittas is habitat loss in the form of rapid deforestation, but they are also targeted by the cage-bird trade. They are popular with birdwatchers because of their bright plumage and the difficulty in seeing them.

Taxonomy and systematics

The first pitta to be described scientifically was the Indian pitta, which was described and illustrated by George Edwards in 1764. Carl Linnaeus included the species in his revised 12th edition (1766–1768) of the Systema Naturae based on Edwards' descriptions and illustrations as well as other accounts, placing it with the Corvidae as Corvus brachyurus. Ten years later Statius Müller moved it and three other pittas to the thrush family Turdidae and the genus Turdus, due to similarities of morphology and behaviour.

Description

The pittas are small to medium-sized passerines, ranging in size from the blue-banded pitta at 15 cm (5.9 in) to the giant pitta, which can be up to 29 cm (11 in) in length. In weight they range from 42 to 210 g (1.5–7.4 oz). Pittas are stout-bodied birds with long, strong tarsi (lower leg bones) and long feet. The colour of the legs and feet can vary dramatically even within a species. This may be a characteristic used by females in judging the quality of a prospective mate.

Distribution and habitat

The pittas are generally birds of tropical forests, semi-forests and scrub. Most species need forests with much cover, a rich understory, and leaf litter for feeding, and they are often found near waterways as well. Some species inhabit swamps and bamboo forests, and the mangrove pitta, as its name suggests, is a mangrove specialist. Several species are lowland forest specialists. For example, the rainbow pitta is not found above 400 m (1,300 ft).

Behaviour and ecology

Sociality and calls

Pittas are diurnal, requiring light to find their often cryptic prey. They are nevertheless often found in darker areas and are highly secretive, though they will respond to imitations of their calls. They are generally found as single birds, even young birds not associating with their parents unless they are being fed. The only exception to their solitary lifestyle is small groups that have been observed forming during migration.

Relationship with humans

The brilliant plumage of many pittas has resulted in considerable interest in pittas from people living within their range, scientists, aviculturists and birdwatchers, and has led to the colloquial name jewel-thrushes. Such is their attractiveness that, in Borneo, even the body of a dead pitta can be a favoured toy for local children. They have proven difficult to maintain and breed in captivity, requiring large amounts of space, humidity and sufficient vegetation of the right kind.

Species of pitta

There are 46 species of pitta in three genera according to the International Ornithological Congress' (IOC) Birds of the World: Recommended English Names.