Sentinel seagull

This is the seagull I call Seamus. He sits on a lamp post outside my bedoom window in the morning and again in the late afternoon. To be honest I don't know how to sex herring gulls, so she might be Seonaid. Either way this bird seems to be the king or the queen of the hill. Intruders are seen off with a low murttering and a disdainful look.