Why didn't the bird cross the road? Because it was afraid of predators and venturing into another bird's territory
Summary: It was once believed that roads posed no problem to birds because of their ability to fly. A new study finds that they can find these human-made structures problematic, especially small, forest-dwelling species. Their hesitance to cross roads could restrict their positive effects on the natural environment, such as seed dispersal, pollination and insect control.