As he and other scientists study the makeup of birds’ nests, they’re looking for signs of human influence. Some birds have begun using insulation, foil, and cigarette butts, for example ...

It is in consequence of this that not only the domesticated, but the so-called wild, animals and birds of this country are far bolder and easier of approach than in other parts of the world.

Take precautions around sick or dead wild birds, experts recommend. But you can keep your bird feeder up. Despite the spread in birds and other wild ... them to their nests, said Richards.