Wednesday, 31 July 2013

Hungry gulls

 2 chicks that have survivied
One of the things we don't study at the moment is how successfully the gulls are at breeding. We count the total number of nests every 2 years but we don't count how many chicks per pair are produced and this year that would have been interesting to know. It is only an impression but this year it seems that the gulls, the lesser black-backed and herring, have been struggling for food. Walking through the colonies and there aren't many live chicks but lots of dead ones. We have also seen fierce predation of the terns and other seabirds, maybe fiercer than other years. It maybe that with other normal food sources such as land fill sites, food waste and by-catch from fishing boats being reduced the gulls are having to look elsewhere. They are supremely adaptable and are able to take advantage of a whole range of food sources. One such food source are their gull neighbours with gulls being quite able to eat their neighbours chicks and eggs. I had a look around the nest of one of the pairs of greater black-backed gulls at the South Ness and it is surrounded with the remains of gull chicks so it is clear where many of the chicks of that area have gone. It is just something that will have to be watched and though herring and lesser black-backed gulls are no so popular with the public as other seabirds they have the same conservation status and protection so can't be ignored.
This is another example of the careful balance that exists and that if it is changed in one way it can be difficult to predict how nature will restore the balance.

 And lots that haven't

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