to A. b. bicolor, but are much paler and have a pearl-grey collar. Under-wing coverts and thighs are rufous. A. b. guttifer; located in South Bolivia and northern Argentina. The underparts of the adult are grey or extensively salmon rufous with large white spots and bars. Habitat and distribution The bicolored hawk is widespread but uncommonly observed. Its range extends from Mexico to west Ecuador, the Guianas to Colombia, south to east Peru, through Amazonian Brazil to Paraguay, north-northwestern Argentina, Bolivia and to Chile. It mainly resides in forest, along forest edges and in clearings in tropical and locally subtropical zones, although its habitat is none too specialized. It may also reside in rain forest, drier, thinned forest, and palm savanna with gallery forest. Forest disturbance and fragmentation negatively affect the habitat and quantity of the bicolored hawk, which is most abundant in primary undisturbed forest or riparian forest. There are fewer hawks in disturbed habitats such as forests that have been logged, and even fewer in those fragmented habitats that provide greater than 66% forest cover. These hawks are rarely present in forests that provide less than 66% forest cover. Behaviour The bicolored hawk is difficult to detect due to its shyness and inconspicuousness. Because of this behaviour, the bicolored hawk may be more common than it seems. Vocalisations Its vocalisations are mainly subdued and unnoticeable. Males have been heard to give a soft, clear whistle and females can emit a loud "cac cac cac" when around the nest and young. A barking "kra-kra-kra-kr-kr-kr-ka" may also be heard from both sexes. During incubation, males give a sharp "kek" vocalisation upon arrival to the nest with food, to which the female replies with a nasal "wreh". Diet These hawks capture prey in a stealthy manner by flying through dense vegetation to ambush unsuspecting prey. They may also capture prey through aerial pursuit after inconspicuously sitting and watching their target. At times, the bicoloured hawk may hunt in pairs. Most commonly, it feeds on smaller birds such as thrushes, mockingbirds and small doves, but has also been known to consume small mammals, including bats, as well as reptiles and large insects. Southern race individuals (or females) are also known to take Chilean pigeons. Several instances where the hawks attack groups of squirrel monkeys or tamarins have been witnessed. In addition, these hawks may follow groups of monkeys in order to feed