Re: San Fran Bell's Vireo
> As far as bill length of a photographed Bell'sVireos (BeVi, or of the
> Western LBVI), one can see variation based on age ofindividual, and a
> bird in head molt may show a longer bill than onewith fully developed
> (new or old) throat and cheek feathers.If the bird is in migration, wont it have either
finished its body molt, or not started it yet?
According to Pyle (1997), the "pre-basic" molt occurs
on the summering ground, so this bird ought to have
already completed its first molt (out of juvenile
plumage) and be in formative (the old first-basic)
plumage by now. So, it would seem that head molt
would not affect the apparent length of this bird's
bill. Just a thought,
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