Green hylia

Hylia prasina is a monotypic songbird that has proven difficult to place within the phylogenetic tree. A sister relationship between Hylia and Aegithalidae (long tailed tits) was similarly poorly supported. Close relationships with Nectariniidae (sunbirds), Estrildidae (finches) and Meliphagidae (honeyeaters) have also been rejected. The sister relationship between Hylia and Pholidornis (tit hylia) is strongly supported, based on mitochondrial data and physiological similarities. It has been suggested that both genera should be placed in a new family 'Hyliidae', pending further confirmation. It is likely that the green hylia, along with other closely related species, have an uncertain position in the phylogenetic tree as a result of rapid radiation of the families within the Sylvioidea. ==Description==

The green hylia has dark brown irises, a black bill and olive green feet. This species is small, weighing approximately 14 g. There is no noticeable difference in colour between the sexes, however males are generally larger. There are two subspecies, H. p. prasina and H. p. poensis, which differ in the colouring under the throat. H. p. prasina has an olive green chin and throat and olive-grey underbelly while H. p. poensis has a white-grey throat and underbelly. Vocalisation The green hylia uses several different calls, the most common being clear whistles (kee kee) or dry scolding rattles (trrit trrrit). When played imitation recordings, males reacted more strongly to longer notes. ==Habitat and distribution==

The green hylia occurs in a wide range throughout most of tropical Africa. The subspecies H. p. poensis can only be found on islands in the Gulf of Guinea. H. p. prasina is much more widely distributed throughout the Guineo-Congolian forest and is found from western Gambia to western Kenya. Green hylia habitat includes plant species such as Elaeis guinensis, Celtis zenkeri, Cola gigantea, Acalypha ornata, Markhamia platycalyx, Coffea canephora, Albizia sp., Fagara macrophylla, Funtumia elastica, Pycnanthes angolensis, Musanga cecropioides and Xylopia aethiopica. ==Ecology==

The green hylia is a foliage-gleaning insectivore of the canopy and forest understory, usually foraging at a height of about 10 metres. Its diet includes insects, ants or butterflies which are accessible in its feeding area, on the underside of leaves or amongst forest litter. The green hylia is usually observed alone or in a mating pair. Mating pairs roost together in their nest. The eggs are white and otherwise not very distinctive. The nest is built a few feet from the ground in a suitable location, such as the vertical forks of young palm trees. The nest is oval and domed in shape with a 20 mm circular opening at the side of the top. Nests are crumbly and friable, the bulk being made up of loose tufts of plant matter which are not fragmented, interwoven or compacted. The outside is covered by a fine layer of fibrous strips topped with the occasional leaf skeleton. The nest measures 150 mm from top to bottom and 90 mm side to side and front to back. It differs from that of other sunbirds in that it is positioned in forks of vegetation and not suspended in the air. ==Threats==

The green hylia is currently classified as Least Concern by the IUCN based on large population numbers and wide distribution. Parasites in African habitats may affect the species. Plasmodium parahexamerium was identified as infecting the green hylia in 2009, with as yet unclear ramifications. This parasite was thought to only inhabit New World hosts, thus its appearance in an Old World bird is both interesting and concerning. Despite this, parasites are not known to be a significant threat to the species as a whole. ==References==