It's funny you should mention seagulls! I used to live in a town on the Welsh coast with enormous seagulls which would often display their intelligence and coordination. They'd sometimes even appear to work in groups to steal food off people, though they tended to fight for it afterwards.

>I wonder if the same could be done with Corvidae

Possibly. Food sharing is a huge part of socialising and pairing for corvids. For a lot of species the breeding season is started with food begging and sharing.