Seabird makes citrusy bug repellant

Alaskan seabirds called crested auklets carry a citrus-smelling chemical in their feathers that could be one of the few examples ever found of a homegrown avian pest repellant.

Birds rub on themselves all kinds of substances alleged to repel pests, but biologists have found few species that grow their own chemical defenses, says Hector D.