Visited us in the snow along with Goldfinches, Dunnocks and Siskins
Hi,
the bird appears to be a leucistic Goldfinch. The bill, primary projection and soft part colours seem to fit. The tail fork doesnt seem deep enough for a Siskin neither does the bill seem long enough for that spp. Greenfinch can be eliminated on size. Lesser Redpoll would have a stubbier bill and a deep tail fork .
:)
S
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Leucism = some or all of the feathers are white, due to an absence of the two melanin pigments. I don't see how leucism would turn normally white feathers (like those on a goldfinch's cheeks) yellow. The term for excess yellow pigment is xanthochromism, but I'm not sure that's what's going on here either. There is a very good paper available online about aberrant colour forms here: http://www.vogelringschier.nl/DB28%282%2979-89_2006.pdf (I've linked it here before). It includes some leucistic Goldfinches and various other oddballs.
The ghosted face pattern on this bird reminds me of a male Siskin. De-pigmented feathers are weaker and wear faster, which could explain the blunt tail tip. As for the pigment issues, not sure. Going by the paper I linked I guess it would be a dilute or 'pastel' :)
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after reading your comments I blew the image up massively- the yellow seems to ghost siskin on the wings too.
I think you're right with male Siskin :)