Dark Bellied Brent Update

Following the post on the 2nd May, feedback has been received from a number of readers:

Per Graham McIlwaine:
In relation to your article, the Svalbard / Greenland breeding birds are from a separate flyway population - the East Atlantic population. Whilst NI birds stage in Iceland and do actually fly over Greenland, they breed in High Arctic Canada, and our birds are called the East Canadian High Arctic (ECHA) population. 
From my own personal observations, this end-of season flush of dark-bellies, mainly juveniles in my experience, is an annual occurrence, usually encountered at places which hold birds late-season, like Dundrum, Killough and the Strangford Narrows. The sites affected are often used  late-season by staging marked pale-bellied Brent which we know have over-wintered in Normandy, France, where pale-bellied and dark-bellied brent geese are both present in considerable numbers. It would therefore be my hypothesis that these birds are being sucked into the migration of “our” birds at the southern limit of the range. I chatted to one of the Icelandic guys last week, and they regularly encounter small numbers of dark-bellies, which are presumably the same ones. Indeed, one (an adult) was caught in one of our catches there last week.

Per Alain Livory, France: 
Concerning the flocks of brent in Regnéville, France, most of the time pale and dark bellies are mixed on the salt marshes even if roughly each species keeps more or less together grazing. Dark-bellied Brent arrive first and were more numerous in the very begining of the winter season but things are quickly reversing and pale-bellied are nowadays more numerous than the dark ones unlike in the past.

Light and Dark Bellied Brent, Kinnegar Shore, 14th May 2017 - Ronald Surgenor:

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