Gull On The Roof

I spotted this gull on a roof in the industrial area when I went to get petrol and screen wash. Gulls can be quite tricky to identify. I think this might be an immature lesser black-backed gull. The red spot on its bill can just be seen. This got me thinking of a programme I saw a long time ago about Niko Tinbergen and his classic experiments on gull behaviour. Newly hatched gulls peck at this spot which encourages the parent to regurgitate food for them. Tinbergen found that the chicks respond to supernormal stimulus, they will peck even more vigorously at a larger red spot on a long stick.