Individual and Intersexual Variation in Alarm Calls of the White-Tailed Hawk

Abstract

Although variation in bird vocalizations is well-studied (Marler 1960, Beer 1970, Jellis 1977, Falls 1982, Brown and Farabaugh 1991), few falconiforms have been intensively examined. The White-tailed Hawk (Buteo albicaudatus), however, exhibits remarkable patterns of intersexual as well as individual variation (Farquhar 1986) not previously identified in this species (Brandt in Bent 1937, Stevenson and Meitzen 1946, Slud 1964, Snyder and Snyder 1991). Hereafter referred to as alarm calls in White-tailed Hawks, these loud vocalizations are given in the context of potential danger such as when their territory has been intruded by mate or food competitors, nest predators, or humans. In Falconiformes, alarm calls (also known as territorial calls) gen-