Western Bonelli's warbler

Western Bonelli's warbler
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Passeriformes
Family:	Phylloscopidae
Genus:	Phylloscopus
Species:	P. bonelli
Binomial name
Phylloscopus bonelli (Vieillot, 1819)
Range of P. bonelli   Breeding   Passage   Non-breeding

The western Bonelli's warbler (Phylloscopus bonelli) is a warbler in the leaf warbler genus Phylloscopus. It was formerly regarded as the western subspecies of a wider "Bonelli's warbler" species, but as a result of modern taxonomic developments, they are now usually considered to be two species:[2][3]

• Western Bonelli's warbler, Phylloscopus bonelli, which breeds in southwest Europe and north Africa
• Eastern Bonelli's warbler, Phylloscopus orientalis, which breeds in southeast Europe and Asia Minor

The breeding ranges of the two species do not overlap; while their appearance and songs are very similar, the calls are completely different (see below). They also show marked difference in mtDNA sequence.[4]

The species is migratory, wintering in sub-Saharan Africa. It is a rare vagrant in Northern Europe.

The genus name Phylloscopus is from Ancient Greek phullon, "leaf", and skopos, "seeker" (from skopeo, "to watch").[5] The English name and the specific bonelli are for the Italian ornithologist Franco Andrea Bonelli.[6]

Description

Western Bonelli's warbler at Aosta Valley, Italy

Western Bonelli's warbler is a small passerine bird, found in forest and woodland. Four to six eggs are laid in a nest on the ground. The eggs are white with reddish-brown markings and are laid in clutches of 3-5 eggs. The incubation period is around 14 days long, and the chicks fledge after 10-14 days.[7] Cuckoo nest predation and brood parasitism are major hazards to the breeding success of western Bonelli's warblers.[8] Like most warblers, western Bonelli's warbler is insectivorous.

The adult has a plain grey-green back, green-toned rump and wings and whitish underparts. The bill is small and pointed and the legs brown. The sexes are identical, as with most warblers.

The western Bonelli's warbler has a browner tinge to the upperparts than the eastern Bonelli's warbler; the latter sometimes has a greenish tinge instead. The song is a fast monotone trill, only slightly different from eastern Bonelli's, and also with some similarity to the wood warbler. The call of the western Bonelli's warbler is a disyllabic hu-it, differing from that of the eastern Bonelli's warbler which is a hard chup, reminiscent of a crossbill or a house sparrow.[9]

Phylloscopus bonelli - MHNT

References

1. BirdLife International. (2016). "Phylloscopus bonelli". IUCN Red List of Threatened Species. 2016: e.T22715255A87665883. doi:10.2305/IUCN.UK.2016-3.RLTS.T22715255A87665883.en. Retrieved 7 October 2021.
2. Parkin, David T. (2003): Birding and DNA: species for the new millennium. Bird Study 50(3): 223–242. HTML abstract
3. Sangster, George; Knox, Alan G.; Helbig, Andreas J. & Parkin, David T. (2002): "Taxonomic recommendations for European birds. " Ibis 144(1): 153–159.
4. Helbig, A. J.; Seibold, I.; Martens, J. & Wink, M. (1995): Genetic differentiation and phylogenetic relationships of Bonelli's Warbler Phylloscopus bonelli and Green Warbler P. nitidus. J. Avian Biol. 26: 139–153.
5. Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 305. ISBN 978-1-4081-2501-4.
6. Beolens, Bo; Watkins, Michael (2003). Whose Bird? Men and Women Commemorated in the Common Names of Birds. London: Christopher Helm. p. 59.
7. Roncalli, Gianluca; Ibáñez-Álamo, Juan Diego; Soler, Manuel (2016-07-02). "Breeding biology of Western Bonelli's Warblers Phylloscopus bonelli in the Mediterranean region". Bird Study. 63 (3): 413–424. doi:10.1080/00063657.2016.1215408. ISSN 0006-3657. S2CID 88649351.
8. Roncalli, Gianluca; Ibáñez-Álamo, Juan Diego; Soler, Manuel (2016-07-02). "Breeding biology of Western Bonelli's Warblers Phylloscopus bonelli in the Mediterranean region". Bird Study. 63 (3): 413–424. doi:10.1080/00063657.2016.1215408. ISSN 0006-3657. S2CID 88649351.
9. Helb, H.-W.; Bergmann, H.-H. & Martens, J. (1982): Acoustic differences between populations of western and eastern Bonelli's Warblers (Phylloscopus bonelli, Sylviidae). Cellular and Molecular Life Sciences 38(3): 356–357.

External links

• Ageing and sexing (PDF; 2.5 MB) by Javier Blasco-Zumeta & Gerd-Michael Heinze