Questions?

Today I looked out of my window and saw a scene from the birds. well not quite cos these birds are sea gulls. I don't live anywhere near the sea so where do these gulls come from?

A car drove down the road past them and they all lifted into the air and flew together then landed back on tge ground. Lots of them.

They just arrived. They had a little poke about on the newly spreaded field, which, incidently stinks, then they flew off as quickly as they arrived.

Where did they go? Why did they come here? My final question has had me guessing for years! Where do sea gulls sleep?