Fields, utility roadways, and power lines are invading the interior forests. The smaller an interior forest becomes, the smaller the microhabitat is for the species to exist. Areas of habitat, like interior forests, are losing their integrity because the exterior buffers are decreasing. This decrease in exterior forests causes competition for space among species. One concern is the decrease in habitat for migratory songbirds.
Eastern forests provide critical nesting habitat for Neotropical migratory songbirds.
Among various factors contributing to these population declines, nest parasitism by brown-headed cowbirds has received the most attention in the central hardwood forests. The cowbird averages eighteen centimeters in length. The female cowbird does not spend the time and energy involved in building a nest. She will locate the nest of some other species to incubate her eggs and feed her offspring. The cost of reproduction for the songbird is being greatly affected by the parasitism of the cowbird.