Old World warblers are a large group of birds formerly grouped together in the bird family Sylviidae. They are not closely related to the New World warblers. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the cisticolas into Cisticolidae and the kinglets into Regulidae. In the past ten years they have been the subject of much research and many species are now placed into other families, including the Acrocephalidae, Cettiidae, Phylloscopidae, and Megaluridae. In addition some species have been moved into existing families or have not yet had their placement fully resolved. A smaller number of warblers, together with some babblers formerly placed in the family Timaliidae and the parrotbills, are retained in a much smaller family Sylviidae.
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds that make up the family Parulidae and are restricted to the New World. The family contains 120 species. They are not closely related to Old World warblers or Australian warblers. Most are arboreal, but some, like the ovenbird and the two waterthrushes, are primarily terrestrial. Most members of this family are insectivores.
Sylviidae is a family of passerine birds that includes the typical warblers and a number of babblers formerly placed within the Old World babbler family. They are found in Eurasia and Africa.
The family Cisticolidae is a group of about 160 warblers, small passerine birds found mainly in warmer southern regions of the Old World. They were formerly included within the Old World warbler family Sylviidae.
Gray's grasshopper warbler, also known as Gray's warbler, is a species of grass warbler in the family Locustellidae; it was formerly included in the "Old World warbler" assemblage.
Passerida is, under the Sibley-Ahlquist taxonomy, one of two parvorders contained within the suborder Passeri. While more recent research suggests that its sister parvorder, Corvida, is not a monophyletic grouping, the Passerida as a distinct clade are widely accepted.
The Manchurian bush warbler, also known as Korean bush warbler, is a bird in the family Cettiidae. The species was first described by Robert Swinhoe in 1860. It is found in northeastern China.
Locustellidae is a newly recognized family of small insectivorous songbirds ("warblers"), formerly placed in the Old World warbler "wastebin" family. It contains the grass warblers, grassbirds, and the Bradypterus "bush warblers". These birds occur mainly in Eurasia, Africa, and the Australian region. The family name is sometimes given as Megaluridae, but Locustellidae has priority.
The chestnut weaver is a species of bird in the family Ploceidae. It is found in eastern and south-western Africa.
Sylvioidea is a superfamily of passerine birds, one of at least three major clades within the Passerida along with the Muscicapoidea and Passeroidea. It contains about 1300 species including the Old World warblers, Old World babblers, swallows, larks and bulbuls. Members of the clade are found worldwide, but fewer species are present in the Americas.
The African warblers are a newly erected family Macrosphenidae, of African songbirds. Most of the species were formerly placed in the Old World warbler family Sylviidae, although one species, the rockrunner, was placed in the babbler family, Timaliidae. A series of molecular studies of the Old World warblers and other bird families in the superfamily Sylvioidea found that the African warblers were not part of Sylviidae but were instead an early (basal) offshoot of the entire clade Sylvioidea. Some taxonomic authorities place the entire family Hyliidae here.
