Monday, 21 October 2013

White-crowned sparrow still on show today!

Today, the wind continued to blow strongly from West, making birding and photographing rather difficult on Corvo. A few new birds were nevertheless discovered along the day including two Indigo buntings (Middle Fields) by Darryl Spittle and Stefan Ettestam, and a female Rose-breasted grosbeak by the Polish team. The Scarlet tanager was also briefly re-observed in flight over the Middle Fields this morning by Darryl but proved once again very elusive for the other birders who did not manage to relocate it and thus dipped out for the second consecutive day!

Indigo bunting (1st winter), 21 October 2013, Middle Fields, Corvo (Photo courtesy of D. Spittle)
For most birders, however, it was the White-crowned sparrow - initially discovered yesterday evening and fortunately relocated this morning at the very same spot - which attracted most of our attention today. This interest arose from some developments that came out in the middle of last night when an ornithologist from the other side of the Atlantic pointed out that the bird could perhaps be of the western 'gambelii' subspecies (Taiga breeders west of Hudson Bay up to Canadian Rockies and Alaska) - rather than from the eastern nominate 'leucophrys' subspecies. This preliminary diagnostic was established based on a few distinctive features shown by 'gambelii' individuals such as pale lores and orange bill, which is rather contrasting with dark lores and pink bill typically shown by nominate birds. There is, however, an intergradation zone between 'leucophrys' and 'gambelii' where a certain number of individuals show gambelii-type characters, so the assignment of our bird as a 'gambelii' is only speculative at this stage. The only certainty tonight is that our bird is not a 'leucophrys', and thus is coming from further West than all previous records in the Western Palearctic, which have been from nominate birds!

Breeding range of 5 White-crowned sparrow subspecies (cf. Weckstein et al. 2001; Auk 118: 231-236)
Adult White-crowned sparrow (gambelii-type individual), 21 October 2013, Middle Fields, Corvo
Adult White-crowned sparrow (gambelii-type individual), 21 October 2013, Middle Fields, Corvo
Special thanks here must go to Frode Jacobsen for initially bringing our attention to the interesting features shown by this bird, for providing supporting literature, and overall for fruitful discussions on the ID of this bird. For more information, check out

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