Friday, 1 February 2013

Herring Gull (Larus argentatus) with extensive white coloration

A rather pale 2cy argentatus Herring Gull which slightly recalls some birds labeled as hybrid hyperboreus x argentatus (Viking Gull). Compared to normal-looking Herring Gulls it has paler tail band and very much white as well, recalling marinus, more barred tertials, less black along the feather shaft in the scapulars and fainter facial mask. All these features point towards some influence from Glaucous Gull genes and some people argue that this kind of phenotypic variation result from introgression of Glaucous Gull genes, at present or in the past, along the northern parts of the Herring Gull range. However, as we also see such extreme individuals with extensive white coloration among local breeding birds in Denmark one could also argue that these are only pale extremes of the variation within the argentatus subspecies of Herring Gull. It was photographed on January 16, 2013 at Fiskerihavn Copenhagen.
Note paler tertials and greater coverts compared to the normal argentatus Herring Gulls

In Finland there is a continuous sequence of Herring Gull plumages from the more common darker Herring Gulls to these pale Herring Gulls

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