The name Seagull is misleading. Although found near coastal areas and, even more misleadingly, at sea taking pickings from trawler catches, this bird is land based and has no natural affinity for the sea. Unseen by most people is the vast flocks of Seagulls feeding of our landfill sites, successfully breeding and thriving solely from human organic waste.
In fact one can take this further to this bird's relationship us. They are bullish scavengers that have learned to cohabit human areas of population to exploit our redundant food waste, and sometimes not only redundant. Ever had your ice cream or chips stolen by a dive bombing Seagull? Precisely! It is then that we realise that very few Seagulls eat ONLY wild foods, but scavenge and exploit any opportunities given to them from ONLY + ALL land based sources.
(My person opinion is that they're aggressive noisy buggers and plague more seaside walks!!!)
IHI