Factors affecting the choice of hunting method by American Kestrels

Includes bibliographical references (pages 53-56)Foraging American Kestrels (Falco sparverius) were\ud observed in order to determine how they choose between the\ud two primary hunting techniques; perch hunting and hover\ud hunting. If kestrels forage optimally, the energetically\ud more expensive hovering technique must result in a greater\ud energy gain from captured prey than does the perch hunting\ud technique. In addition to calculating the energy budgets\ud that would answer this question, environmental factors\ud which might influence choice of hunting method were identified.\ud Variables measured include distance of the strike\ud from the perch, percent ground cover, temperature, percent\ud cloud cover, time of day, and wind speed. The study was conducted at two sites; one in Santa\ud Barbara County and one in Los Angeles County, California. \ud Five-hundred-sixty-one strikes were observed between 5 May\ud and 28 September 1983. Environmental factors whose mean\ud values were significantly different for perch strikes and\ud hover strikes (p