Abstract

Reports of raptors, especially red-tailed hawks (Buteo jamaicensis), with beak abnormalities have been increasingly frequent in the Pacific Northwest during the past few years. The possibility of an underlying environmental toxin has been promoted in the communications media. In an effort to identify some of the factors that may be contributory to “long-billed hawk syndrome”, four Oregon red-tailed hawks with beak abnormalities and two hawks with grossly normal beaks were necropsied. A variety of histopathologic changes were observed in the beaks but the main features were epithelial hyperplasia and parakeratosis, with various degrees of inflammation and damage to supportive connective tissues. Toxicologic, parasitologic, and bacteriologic findings revealed a several potential causative factors but none common to all affected birds. Beak lesions in wild raptors may be more common than previously recognized, making identification of any subset caused by environmental toxins more difficult.