Leaf warblers were formerly included in theOld World warblerfamily but are now considered to belong to the familyPhylloscopidae, introduced in 2006. The family originally included the genusSeicercus, but all species have been moved toPhylloscopus in the most recent classification. Leaf warblers are active, constantly moving, often flicking their wings as they glean the foliage for insects along the branches of trees and bushes. They forage at various levels within forests, from the top canopy to the understorey. Most of the species are markedly territorial both in their summer and winter quarters. Most are greenish or brownish above and off-white or yellowish below. Compared to some other "warblers", their songs are very simple. Species breeding in temperate regions are usually stronglymigratory.
The species are of various sizes, often green-plumaged above and yellow below, or more subdued with greyish-green to greyish-brown colours, varying little or not at all with the seasons. The tails are not very long and contain 12 feathers (unlike the similarAbroscopus species, which have 10 tail feathers). Many species are more easily identified by their distinctive songs than their dull plumage.[2] These are very small passerines with adult body masses that can vary from 3.5 to 17 g (0.12 to 0.60 oz) and in some cases, such as theChinese leaf warbler, are among the lightest passerines anywhere. Several of the larger species are similar in size including thelarge-billed leaf warbler,Radde's warbler and thepale-legged leaf warbler.[3] Total length can vary from 9 to 14.5 cm (3.5 to 5.7 in).[4]
Its members occur in Eurasia, ranging intoWallacea and Africa with one species, theArctic warbler, breeding as far east asAlaska. Many of the species breed at temperate and high latitudes in Eurasia and migrate substantial distances to winter in southeastern Asia, India, or Africa. One example isTickell's leaf warbler, which breeds in scrub at high elevation in the Himalayas and on the Tibetan Plateau and then moves down-slope and south to winter in the Himalayan foothills of India and Burma.[5] Most live in forest and scrub and many are canopy or sub-canopy dwellers.
The genusPhylloscopus was introduced by the German zoologistFriedrich Boie in 1826 to accommodate a single species, thewillow warbler, which is therefore considered as thetype species.[6][7] The name combines theAncient Greekphullon meaning "leaf" andskopos meaning "seeker" (fromskopeo, "to watch").[8]Phylloscopus is the only genus placed in the family Phylloscopidae that was introduced in 2006 by the Swedish ornithologistPer Alström and coworkers.[9]
Cladogram showing the family relationships based on a study by Carl Oliveros and colleagues published in 2019.[10] The number of species is taken from the bird list maintained byFrank Gill,Pamela Rasmussen and David Donsker on behalf of theInternational Ornithological Committee (IOC).[11]
The genus contains 81 species.[11] Of these, eleven species were formerly placed in the genusSeicercus, but a 2018 molecular phylogeny study indicated that the genusSeicercus is a synonym ofPhylloscopus, leaving the family Phylloscopidae with a single genus,Phylloscopus.[12]
Thealpine leaf warbler,Phylloscopus occisinensis, was reclassified as conspecific withTickell's leaf warbler (P. affinis) by the IOC, but other authorities such as eBird still consider it distinct.[14][16]
^Dunning, John B. Jr., ed. (2008).CRC Handbook of Avian Body Masses (2nd ed.). CRC Press.ISBN978-1-4200-6444-5.
^Winkler, D. W., S. M. Billerman, and I.J. Lovette (2020).Leaf Warblers (Phylloscopidae), version 1.0. In Birds of the World (S. M. Billerman, B. K. Keeney, P. G. Rodewald, and T. S. Schulenberg, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.
^Alström, P.; Ericson, P.G.P.; Olsson, U.; Sundberg, P. (2006). "Phylogeny and classification of the avian superfamily Sylvioidea".Molecular Phylogenetics and Evolution.38 (2):381–397.doi:10.1016/j.ympev.2005.05.015.PMID16054402.
