the life of birds - bird brains the scene - a traffic light crossing: When the lights change, the birds hop in front of the cars and place walnuts, which they picked from the adjoining trees, on the road. After the lights turn green again, the birds fly away and vehicles drive over the nuts, cracking them open. Finally, when it's time to cross again, the crows join the pedestrians and pick up their meal. /PBS via Biz Stone