I saw a documentary about ravens (I think it was set in England). They eat these nuts from trees that line a street. They're not strong enough to crack them, so they drop them on the street and wait for cars to run them over. Pretty smart, eh? It gets better...

I guess they figured that this approach was too dangerous, so they decided to start dropping them at intersections and then...

wait for the light to change red before swooping down to collect their spoils!