Some Prey Preference Factors for a Red-tailed Hawk

SEW•AL studies have reported selection against conspicuous prey. Dice (1947) reported differential selection against conspicuous phenotypes of mice (Peromyscus maniculatus) and Kaufman (1974a) showed that Barn Owls (Tyto alba) and Screech Owls (Otus asio) selected against conspicuous phenotypes of old field mice (Peromyscus polionotus). Metzgar (1967) reported that Screech Owls preferred transient white4ooted mice (Peromyscus leucopus) over resident ones in a laboratory experiment. Metzgar suggested that transient mice may be more active and thus more conspicuous to a predator than residents. Prey activity was suggested as a conspicuousness factor by Cushing (1939) and Ingles (1940). Kaufman (1974b) reported support for a prey activity explanation. He allowed Barn Owls to select either an active (live) or inactive (dead) house mouse (Mus musculus) in a field enclosure. The owls preferred significantly more of the live mice. The purpose of the present study was to examine further the role of activity in prey selection. The first of three experiments reported here examined the role of prey activity when a Red-tailed Hawk (Buteo jamaicensis) was offered a choice between two live prey animals. The second experiment examined changes in prey activity preferences when the hawk was offered two comparatively large prey animals. In the third experiment the hawk was offered two prey of different weights, to determine if this would affect the selection against more active prey.