Greenish Warbler

Taxobox
name = Greenish Warbler


image_width = 250px
image_caption = Green Warbler "Phylloscopus (trochiloides) viridianus"
status = LC
status_system = iucn3.1
status_ref = [IUCN2006|assessors=BirdLife International|year=2004|id=52599|title=Phylloscopus trochiloides|downloaded=12 May 2006 Database entry includes justification for why this species is of least concern]
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Passeriformes
familia = Phylloscopidae
genus = "Phylloscopus"
species = "P. trochiloides"
binomial = "Phylloscopus trochiloides"
binomial_authority = (Sundevall, 1837)
subdivision_ranks = Subspecies
subdivision = see text

The Greenish Warbler, "Phylloscopus trochiloides", is a widespread leaf-warbler throughout its breeding range in northeast Europe and northern Asia.

It breeds in lowland deciduous or mixed forest. The nest is on the ground in low shrub. Like its relatives, this small passerine is insectivorous.

This warbler is strongly migratory and winters in India.

This is a typical leaf-warbler in appearance, greyish-green above and off-white below. Its single wing bar distinguishes it from most similar species, except Arctic Warbler, "Phylloscopus borealis". It is slightly smaller than that species and has a thinner bill, without a dark tip to the lower mandible. Its song is a high jerky trill.

This species occurs as a spring or early autumn vagrant in western Europe and is annual in Great Britain.

ystematics

Like all leaf-warblers, it was formerly placed in the "pan-Sylviidae" assemblage, but now belongs to the new leaf-warbler family Phylloscopidae (Alström "et al." 2006). It has a number of subspecies, of which "P. t . viridianus" is the most familiar in Europe (Snow "et al." 1998). This is due to its evolution as a ring species, with populations evolving to the East and West of a plateau, later meeting on the other side, by which time there are two species. Their relationships are therefore fairly confusing (see Alström 2006):

Eastern group: Greenish Warblers
* "Phylloscopus trochiloides trochiloides": Greenish Warbler:Southern rim of the Himalaya eastwards from Nepal into W China.:Dusky greyish green above, often traces of second wing bar.
* "Phylloscopus trochiloides obscuratus": Dull-green Warbler:Intermediate between "trochiloides" and "plumbeitarsus".:Gansu and surroundings, China.
* "Phylloscopus trochiloides plumbeitarsus": Two-barred Warbler:Breeds Eastern Siberian taiga.:Supercilium more yellow; upperparts more vivd green. 2 well-marked wing bars.

Western group: Green Warblers
* "Phylloscopus trochiloides viridanus": Western Greenish Warbler:Breeds Western Siberia to north-east Europe; at east of range south to NW India.:Dull green above, with yellowish supercilium, throat, breast and faint wing bar.
* "Phylloscopus trochiloides nitidus": Green Warbler or Bright-green Warbler:Caucasus region.:Brighter; underside much more yellow. One strong and one faint wing bar, especially in young birds.

"P. t. plumbeitarsus" is often split as distinct species, but phylogenetically, the western taxa are even more distinct.

Another approach to the systematics of this complex is to consider it a ring species. The groups' origin lies probably in the Himalayan region, where "trochiloides" is found. This taxon is close to the parapatric "obscuratus" and "plumbeitarsus" which is geographically separated from "obscuratus".

On the other hand, there is some gene flow between "trochiloides" and the more distinct "viridianus" also, with their hybrids being especially common in Baltistan and once considered a subspecies "ludlowi". On the other hand, "viridianus" whereas the latter and "plumbeitarsus" do not hybridize in the narrow zone in the western Sayan Mountains where their ranges overlap. "nitidus" is a mountain isolate that diverged from ancestral "viridianus".

Song structure differs mainly between "trochiloides" and "plumbeitarsus". The former has a fairly uniform, long, and warbling song. Around the Himalayas, song structure is similar, but songs are generally shorter. "plumbeitarsus", on the other hand, has a long song that can be clearly divided into a warbling part, followed by series of up- and downslurred notes. The songs of "obscuratus", and, interestingly, "ludlowi", are short, but contain the downslur elements too; in the latter, they uniquely appear at the "start" of the song.(Irwin 2000)

Gallery

References

Bibliography

* Alström, Per (2006): Species concepts and their application: insights from the genera "Seicercus" and "Phylloscopus". "Acta Zoologica Sinica" 52(Supplement): 429-434. [http://www.actazool.org/downloadpdf.asp?id=5099 PDF fulltext]

* Alström, Per; Ericson, Per G.P.; Olsson, Urban & Sundberg, Per (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

* Irwin, Darren E. (2000): Song variation in an avian ring species. "Evolution" 54(3): 998–1010. DOI:10.1554/0014-3820(2000)054 [0998:SVIAAR] 2.3.CO;2 [http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1554%2F0014-3820%282000%29054%5B0998%3ASVIAAR%5D2.3.CO%3B2 HTML abstract]

* Snow, David W.; Perrins, Christopher M.; Doherty, Paul & Cramp, Stanley (1998): "The complete birds of the western Palaearctic on CD-ROM". Oxford University Press. ISBN 0192685791

External links

* [http://www.bsc-eoc.org/avibase/species.jsp?lang=EN&id=03ED162DD5EA0DD2&ts=1221724337401&sec=summary Avibase]
* [http://www.zoology.ubc.ca/~irwin/GreenishWarblers.html The greenish warbler ring species]
* [http://www.dutchbirding.nl/sounds/sounds.html Calls of the Greenish Leaf-warbler]