Aroclor? 1248 was fed to captive screech owls (Otus asio) at the rate of three ppm in the diet to determine if reproductive effects such as fewer eggs per clutch, lower hatchability, malformation of the chicks, or higher mortality rates of chicks would appear in this raptorial species as they did in chickens. There were no effects on eggshell thickness, number of eggs laid, young hatched, and young fledged from feeding a low level of Aroclor? 1248 to captive screech owls. The polychlorinated biphenyl (PCB) residues found in the eggs of the dosed birds ranged from 3.9 ppm to 17.8 ppm. Background PCB residues in the diet of all experimental birds ranged from non-detected to 0.62 ppm.