Spraying an oil soln. of DDT at 2 lb. per acre on a 117-acre tract of well-drained bottomland forest at the Patuxent Research Refuge, Bowie, Md., on June 5, 1945, had little or no effect on the bird population of the area, with possible exception of the American redstart (Setophaga rulicilla). Considerable evidence showed this species probably was somewhat reduced. The average density of breeding birds in a 31-acre study area at the center of the sprayed area, and of 2 check areas of 32 and 22 acres, respectively, in the same habitat was about 390.5 pairs per hundred acres. Censuses showed a decrease of 11.9% in the bird population of the sprayed area shortly after spraying, compared to drops of 9.7% and 5.3% in the check areas; these differences are not considered significant. 52.2% of 23 nests observed in the sprayed area were successful, compared to 61.5% of 12 nests in a check area. In nearly every case, the cause of destruction or desertion was known definitely to be due to causes other than DDT.