[throwawaymath]

Yeah that's true, and I've seen a number of corvid species (including crows) taking my peanuts and dropping them a few stories. They also like to soak almonds in water to soften them for chewing.

The thing is that there are ample other food sources so whatever you provide needs to be truly exceptional insofar as rewards go. And the crows might not know it's a great reward until they solve the puzzle to get it.

I'm not saying it's impossible, I'm just pessimistic.