Begging Seagulls

They may have the plumage of an adult but their behaviour was very juvenile. They sat up there on the roof and screeched for food but no parent came to feed them.
My first thought was that they would be swooping down to steal our pizzas but they never made a move to do that, even when crumbs were available after the guests had left.
My guess is that the parents had only just stopped feeding them and they were still waiting to be fed. A larger seagull flew by and they took off following that gull. Maybe that was one of the parents and they were still hopeful.