Rooks is clever. They work out how to do things. They innovate. In most cases... Innovation is applied to Food.
We have one of them bird feeders that is made up of two cylindrical seed holders (with individual small perches and feed-holes) which hang from two hooks at the end of a central pole.
Mostly this arrangement means that the larger birds can't sit on the perches and feed from the holes, cos they's too big ... and so the little 'uns get a look in.
But I been having my suspicions that the rooks have cracked this problem. Now and then I would look out the window and spot a rook grabbing a seed from a rhythmically swinging seed holder.
This morning I see the rascal. She maintains her grip on the central pole... or a convenient branch... leans in... grabs one of the metal perches under a feed hole .... pulls it back... and let's it go. The entire seed holder sets itself into a nice pendulum swing - and Rookie just grabs a mouthful when the feed hole returns conveniently to her beak.
Nice One, Rookie.