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Index of Subjects I had an almost all-white Junco at my feeders on Vienna Street this week - white overall, with just a very pale shade of grey on the wings. The House Sparrows chased it off before I could see the eye colour. I think the bill was pink. Is this bird "hypomelanistic"? Cheers, Susann Myers ----- Original Message ----- From: <iamclar@dal.ca> To: <naturens@chebucto.ns.ca> Sent: Friday, January 08, 2010 8:19 PM Subject: [NatureNS] Aneumelanistic House Sparrow at Bauer St., Halifax > All: > > Gareth Harding took me over this afternoon to see the strangely colored > finch or > sparrow visiting his feeder with a flock of House Sparrows. It turned out, > as > expected, to be a House Sparrow, probably a female, that appears a lovely > buff colour all over, with yellow bill and legs. > > This plumage shows why I have been preaching lately to birding friends on > the > inadequacy of terms like "albino" or "leucistic" even qualified as > "partially" > in talking about plumages of birds. It is more accurate and flexible to > use > terms for the absence of particular pigments. This House Sparrow is > "aneumelanistic" in lacking all black pigment (eumelanins) in feathers and > in > the keratin of legs and bill (made of same substances as feathers). It > does not > lack the brown pigments (phaeomelanins)found throughout much of its > plumage. > However, these brown areas don't vary much in tone because the brown areas > in > normal sparrows are also variably dosed with black pigments. There have > been > some buff-coloured crows in recent years that seem to have the same > (genetic?) > defect. An all white crow lacking both black and brown pigments is > "amelanistic" (i.e., both "apheaomelanistic" and "aneumelanistic"). One > with > white patches is "partially amelanistic." One with gray, rather than black > plumage (one in Cambridge, Kings Co., at present, would be > "hypomelanisic"; a > gray bird (e.g. catbird?) that is black, rather than gray, is > "hypermelanistic." None is "albino" or "leucistic." > > This approach helps when other pigments are lacking in birds that aren't > all > black. There have been male N. Cardinals that have pinkish or reddish > faces > instead of black faces. They're not white, and therefore not "albino" or > "leucistic" to even "partial", but they are aneumelanistic - same as this > House > Sparrow. If you see an all white cardinal (with dark eyes), it is > technically > "arhodoxanthic" (lacking red pigments, although other red pigments might > be > involved), yet may still have a black face (if it doesn't, it's also > amelanistic. > > Hope this helps and is not too confusing. I will put a photo of this bird > on the > NS-RBA photo site. > > Cheers, Ian > >
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