There is no gull problem, only a human one. Most seagulls now live inland on rubbish tips. Blame the filthy species who leave piles of rubbish around untreated. Those scavenging birds are only attempting to clean up the land as they once did with sea, before we made it too toxic for them. Give them a bloody medal I say. (I would add 'exterminate the humans' but we seem to be have that already in hand.)