Why are these seagulls obsessing over one building?

Hi,

I've seen similar descriptions in the local press here. They seem to be Lesser black backed gulls in my area, but they are after food from factories in this case. Sometimes flocks of Black headed gulls hunt for swarms of flying ants in this way.

:)

S

awol said:

I live in Central London about 2 Km from the Thames,in a built-up area.  Normally the only gulls we see or hear are fairly high overhead, announcing bad weather to come, and this has been the pattern for 9 years.  About 2 weeks ago a group of 1-12 seagulls started calling and circling low over a 4-story block of flats nearby, which has a couple of very tall plane trees in front of it.  They do this at least once a day, and they don't seem to do anything more than circle this one building from time to time, in a way I've only seen before when birds of prey are flying, except these gulls are low down.  No-one is feeding them and there's no food rubbish about.

Have they got a nest nearby or in the trees?  Has a bird of prey got a nest nearby (seems unlikely, but..)? 

They probably got a nest on the building. Seagulls seem to be doing this more and more.