Fragmentation, it turns out, brings a host of evils. They include so-called edge predators that thrive in disturbed habitats, creatures like raccoons, skunks, opossums, grackles, crows, jays, and rat snakes—all adept nest predators that are rare or absent from deep woods. Fragments also invite brown-headed cowbirds, grassland birds that parasitize the nests of other songbirds (and which were originally restricted to the Great Plains). What’s more, fragmentation dries out the very forest itself, reducing insect abundance and creating other environmental challenges for the nesting birds.
