Your science questions answered.
The gulls we most commonly see in our UK towns are herring gulls. Since the 1960s they have increasingly been migrating inland, away from their coastal habitats, to live and feed: this is largely due to overfishing and the rising sea temperatures associated with climate change (as fish are being forced to greater depths to feed on plankton). The gulls scavenge in landfill sites and are drawn to areas where we feed them. Although often seen as a nuisance, some species of seagulls are now endangered. Without humans, their natural food supply would recover so, on balance, they would be much better off without us.