The crows where I used to hunt deer led me to more than one. They apparently learned to associate peeps with rifles with gut piles. Any time I heard a crow having a hissy fit, I would always check it out, and at least twice that I recall, the crow was making a racket sitting on a branch near the deer, and hung around until I had left the gut pile. Birds in the crow family have smarts that are easily underestimated.
They are also very effective at teamwork. I studied sea lions years ago. I lived on a pupping colony during the spring when pups were all born. When the afterbirth appeared, the crows were keen on getting at it, they seemed to figure that it was some kind of delicacy. But immediately after the birth, the cow was super protective of both the pup and the afterbirth, at least that is what the behaviour appeared like. What the crows would do is one of them would tease and distract the cow's attention away from the afterbirth while the other crow sneaked in there and grabbed a beak full. After a bit, they would share by changing places. This was a regular pattern where I studied, not just a one off. I suspect that the technique gets passed along through observation and learning from other birds.
If you want to get more fascinating examples, google Indonesian Crow intelligence. Some of the things these birds can do bends my brain.