A review of organochlorine pesticide residues in Swainson's hawk eggs

U. s. Fish and Wildlife Service research projects during the last 10 years in the Pacific Northwest resulted in the collecting of a sample egg from 35 Swainson's Hawk nests (Henny and Kaiser, 1979. Murrelet 60:2-5; Henny et al. 1984. Raptor Research 18:41-48). Pesticide residues, eggshell thickness, and reproductive success from these nests will be reviewed. In addition, egg residues from other published studies in the Pacific Northwest and elsewhere will be discussed.