Feeding behavior of Cooper's Hawks at urban and rural nests in southeastern Arizona

We monitored 18 nests of Cooper's Hawks (Accipiter cooperii) in Tucson, Arizona, and 18 nests in rural areas of southeastern Arizona from 1999-2000 to compare feeding behavior of urban- and rural-nesting hawks. We recorded the frequency of prey deliveries, the approximate size and type of prey items, and the behavior of hawks during each delivery. Differences between rates of prey delivery at urban and rural nests decreased as nestlings grew. Rate of prey delivery at urban nests exceeded that at rural nests most during the morning and least at midday. Urban hawks delivered 2.0 ± 1.2 times more prey biomass nestling^-1 hr^-1 to nests than rural hawks. The odds of males delivering prey directly to nests, and of prey items being refused, were 13.6 ± 2.3 and 2.5 ± 1.6 times greater, respectively, at urban nests than at rural nests. Male and female hawks also vocalized more at rural nests than at urban nests. Our data suggest that prey is more abundant and available to hawks in Tucson than in surrounding rural areas. Diet composition of urban- and rural-nesting hawks also differed. Doves comprised 57% of urban prey deliveries, but only 4% of rural prey deliveries, and may explain the high rate of nestling mortality from trichomoniasis, an avian disease caused by a parasitic protozoan, in Tucson.