Naphthalene moth balls do not deter mammalian predators at red-winged blackbird nests.

Researchers often use predator repellents to deter mammalian predators from following their scent trails to nests. The effectiveness of repellents is largely unstudied. We tested naphthalene moth balls, a supposed repellent, and found them to be ineffective in deterring mammalian predators at unoccupied Red-winged Blackbird (Agelaius phoeniceus) nests that we supplemented with Northern Bobwhite (Colinus virginianus) eggs.