John Pilkington's picture

Gull "Rotation"

During the Spring and Summer, the factory roofs and roadside lamp-posts, in an Industrial Estate and neighbouring Retail Park on the outskirts of Newport s-Wales, were well and truly claimed by Herring and Lesser Black-backed Gulls. The roofs as nesting sites and the lamp-posts as perches, as they have been for several years.

Recently, most of these seem to have "moved on"; is it likely that they have gone to sea or just found other on-land locations with better food opportunities?

Their place seems to have been taken by small groups of Black-headed Gulls (winter plumage)- something I haven't noticed before. Is it likely that they have taken over only because the bigger birds' bullying would have kept them out beforehand?

Any other, perhaps more scientific, views on this "rotation"?

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ophrys's picture

Rotation

The larger gulls have probably gone South, in the case of the Lesser Black Backs, probably to Southern Spain or somewhere similar. The Herring Gulls will also have moved South, though maybe not so far. In contrast, the Black-headed Gulls have moved away from their breeding colonies and are now filling that niche. Nothing to do with competition, I suspect, just different species wintering in different areas.

Ian
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