Displays and Vocalizations of the Sparrow Hawk

I N the past several years I have kept eight Sparrow Hawks (F&o sparverius) in captivity for use in experiments in prey selection and the motivation for predatory behavior. Four of the birds were taken from nests at approximately two to three weeks of age and were hand-reared in my laboratory and four were trapped as free-flying birds. All birds were handled frequently and became quite tame. The continuous presence of the birds in my laboratory and various experimental manipulations provided an opportunity to observe closely a variety of displays and vocalizations used by this species in social behavior. Cade (1955) p er ormed f experiments with both taxidermist’ s mounts and live, captive Sparrow Hawks placed in the winter territories of wild individuals of the species. Willoughby and Cade (1964) maintained breeding pairs of F. sparverius in captivity and carefully observed courtship and other behaviors. I report here only my observations which are new, differ from, or extend the observations of Cade and Willoughby. Displays directed to the experimenter and to my captive Broad-winged Hawks (Buteo phtyp terus) are included along with the displays performed with conspecifics. The birds were maintained on block perches to which they were attached by leashes approximately 35 cm long. Displays between birds occasionally occurred when two perches were placed on a bench in sufficient proximity for the birds to approach each other. Some pairings of adversaries produced frequent and prolonged interactions, others none. Displays directed to the experimenter occurred when he or she, or more particularly, when the hand approached the bird on its perch. Displays in response to the captive Broadwinged Hawks occurred when the Buteo was carried to the near vicinity of the Sparrow Hawk.