Aerial applications of DDT in oil at the rate of 2 pounds per acre applied over a 4-yr. interval on bottomland forest at the Patuxent Research Refuge resulted in a 26% decrease in the breeding bird population by the 5th spring. The American redstart (Setophaga ruticilla), parula warbler (Parula americana), and red-eyed vireo (Vireo olivaceus) suffered decreases of 44%, 40%, and 28%, respectively, over the 4-yr. period. Only the redstart decreased significantly immediately following application of the spray; a few days after the 1st, 2d, and 5th annual sprayings an avg. of 23% of redstart territories were deserted. No significant decrease was observed for other spp., either immediately following spraying, or over the four-year period.