before sunrise every morning and into the mid-morning. The low-frequency of the sound and the timing at which they tend to communicate makes it possible for them to be heard at great distances in the dense forest canopy. Their calls are thought to delineate territory as breeding pairs will often keep some distance between them. The most typical call heard from both males and females is an eight-second song consisting of three or four ow or ahr notes. Sometimes, the female may produce a 10-second call consisting of between 10-30 more rapid notes increasing in tempo proceeding the regular call. In the beginning, between one and three weeks old, the young make more of a scree sound. However, this changes to single-note ahr calls as they get closer to fledging and some weeks thereafter. Diet The collared forest falcon will catch its prey by first concealing itself in the dense forest canopy before pursuing by flight, or running and hopping along the forest floor. This hunting of animals is thought to be aided by their specialized sense of hearing supported by a more pronounced facial disk, also seen in owls and harriers. Flexible tail feathers are also helpful when going after prey in dense forest areas. Differences were observed in the hunting techniques among individual M. semitorquatus'. The Micrastur species enjoys a wide variety of prey such as birds, mammals, lizards, snakes and insects. In a study conducted from 1990–92, prey items delivered to the females, nestlings and fledglings were counted and identified to species (if possible). 223 prey items were accounted for, 171 of which were identified. Results showed that the largest proportion of the collared forest falcon's diet consisted of mammals (46.2%). Then, 34.5% were birds, 18.7% reptiles and 0.6% amphibians. Prey ranged from smaller 20 g to very large 2.7-3.2 kg. Comparisons with the diet of its relative the barred forest falcon (Micrastur ruficollis) showed that the collared forest falcon had a mean prey weight that was 10 times greater. Since the M. semitorquatus is three times larger than M. ruficollis , a comparaison with another larger raptor could prove more interesting in terms of dietary overlap. Reproduction Courtship activities including vocalizations, searching and guarding of nest sites, prey exchanges and copulation occur during the dry season from January to March. Egg laying spans a 30-day period, peaking during the month of march. Next, the incubation period