Pitta

Pittas are a family, Pittidae, of passerine birds found in Asia, Australasia and Africa. There are thought to be 40 to 42 species of pittas, all similar in general appearance and habits. The pittas are Old World suboscines, and their closest relatives among other birds are the broadbills 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 (5.9–9.8 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. 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. In 1816 Louis Vieillot moved it to the new genus Pitta. The name is derived from the word pitta in the Telugu language of South India meaning 'small bird'. The family's closest relatives have for a long time been assumed to be the other suboscine birds (suborder Tyranni), and particularly the Old World suboscines; the broadbills, asities and the New World sapayoa. These arboreal relatives were formerly treated as two families, and are now either combined into a single taxon or split into four. A 2006 study confirmed that these were indeed the closest relatives of the pittas. The clade they form, the Eurylaimides, is one of the two infraorders of suboscines, which is one of three suborders of the passerine birds. With regards to their relationship within the Eurylaimides, another 2006 study placed the pittas as a sister clade to two clades of broadbills and asities. This same study postulated an Asian origin for the Eurylaimides and therefore the pittas. Two DNA studies, from 2015 and 2016, came to a different conclusion, finding that the Eurylaimides were divided into two clades and that the pittas formed a clade with the broadbills of the genera Smithornis and Calyptomena, with the remaining broadbills and asities in the other clade. The 2016 study also disputed the earlier claims about the origin of the group, and concluded that the most likely ancestral home of the pittas and the Eurylaimides was Africa (the sapayoa having diverged before the core clades had reached Africa). The study found that the pittas diverged from the Smithornis and Calyptomena broadbills 24 to 30 million years ago, during the Oligocene. The pittas diverged and spread through Asia before the oscines (suborder Passeri) reached the Old World from Australia. The number of pitta genera has varied considerably since Vieillot, ranging from one to as many as nine. In his 1863 work A Monograph of the Pittidae, Daniel Elliot split the pittas into two genera, Pitta for the species with comparatively long tails and (the now abandoned) Brachyurus for the shorter-tailed species. Barely two decades later, in 1880/81, John Gould split the family into nine genera, in which he also included the lesser melampitta (in the genus Melampitta) of New Guinea, where it was kept until 1931 when Ernst Mayr demonstrated that it had the syrinx of an oscine bird. Philip Sclater's Catalogue of the Birds of the British Museum (1888) brought the number back down to four – Anthocincla, Pitta, Eucichla, and Coracopitta. Elliot's 1895 Monograph of the Pittidae included three genera split into subgenera Anthocincla, Pitta (subgenera Calopitta, Leucopitta, Gigantipitta, Hydrornis, Coloburis, Cervinipitta, Purpureipitta, Phaenicocichla, Monilipitta, Erythropitta, Cyanopitta, Galeripitta, Pulchripitta, Iridipitta), and Eucichla (subgenera Ornatipitta, Insignipitta). Modern treatments of taxa within the family vary as well. A 1975 checklist included six genera, whereas the 2003 volume of the Handbook of the Birds of the World, which covered the family, placed all the pittas in a single genus. Writing in 1998, Johannes Erritzoe stated that most contemporary authors considered the family to contain a single genus. Before 2006 the family was not well studied using modern anatomical or phylogenetic techniques; two studies, in 1987 and 1990, each used only four species, and comparisons amongst the family as a whole had relied mostly on external features and appearances.