[Tweeters] More on white-spotted Dark-eyed Juncos

johntubbs at comcast.net johntubbs at comcast.net
Fri Mar 6 15:55:42 PST 2009




Hi everyone,




>From replies both on and off list, it's apparent that white-cheeked (or almost white-headed) Dark-eyed Juncos (DEJU) are definitely out there in the population.  Off list, one person indicated that there is a theory that a window-crash injury to a bird could cause issues that would lead to a lack of melanin (the pigment that causes dark colors in feathers) in certain areas.  If I recall correctly, fully-grown feathers are lifeless (similar to toenails and fingernails in humans) and it would therefore not seem possible for an injury to affect pigment in a fully-formed feather.  It also (an assumption on my part) seems unlikely that an injury would cause the lack of pigment in a specific area or feather tract, as appeared to be the case in the bird in our yard.  It would seem more likely to be something atypical in the genetic code of a bird that would cause the unusual pigmentation. 




Dennis P. and others out there - are there any indications of environmentally (injury) induced white plumage?  Are there any studies indicating that 'once a leucistic bird, always a leucistic bird' - i.e. the abnormal plumage is repeated in subsequent moltings?  Or is this one of the many areas about birds that are not completely understood yet?



Thanks,



John Tubbs

johntubbs at comcast.net

Snoqualmie, WA


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