fredag den 21. marts 2014

'Pseudo-African Chaffinches' in Northern Europe

In most north European countries there have been records of birds with features which on a few or even multiple plumage characters are reminiscent of male African Chaffinches and thus have appeared markedly different from normal European Chaffinch (Fringilla coelebs coelebs).

In Denmark, we have also had several such records and they have shared a tendency to show a green or greenish (rather than a rich warm brown) mantle tone, some degree of pale pink underparts and blue-grey ‘hood’ combined with distinct whitish eye crescents. At present we know of this and this from the island Amager near Copenhagen; this from Nyborg Strand on Fyn; this, this, this, this and this from the island Læsø in Kattegat; and finally, the one in the photos below which was seen 29 March 2006 on Læsø. In many ways this individual is very similar to a normal coloured nominate Chaffinches and thus different from the other 'pseudo-African Chaffinches' above, but never the less it has more green in the upperparts than normal European Chaffinch and obvious pale eye crescents.

Despite such superficial similarities to North African Chaffinches, several other features have conspired to make such claimed birds differ significantly from typical North African Chaffinches. Consequently none of the birds assessed so far in e.g. Denmark, Sweden, Finland, Norway, Britain and Ireland have been accepted as African Chaffinches.

In fact, there seem to be some common threads running through the claims which amount to a pattern of recurring anomalies. I wonder if most of these 'pseudo-African Chaffinches' might be non-phaeomelanin schizochroic birds as per this paper and which arises due to lack of phaeomelanin (reddish brown pigment) in parts of their plumage or most of their plumage.

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