Take away for one please!

Caught one of our familiar crows pecking away at a few scraps in this plastic box. I think it had contained coleslaw or potato salad maybe.
The other one was hopping about but was a bit more nervous than the one with the box, who obviously wasn't going to have any nonsense if I wanted some of it.
Jonty and Foxy just stood at the play area fence looking at it/her/him. How do you tell the sex of a crow!