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ABSTRACT.-We documented the breeding behavior and diet of a Philippine Eagle (Pithecophaga jefferyi) pair from July 1999 to January 2000 in an isolated forest in Central Mindanao. We observed eight distinct courtship displays and several activity patterns on the nest. Copulation started two months prior to egg laying and continued until the first month of incubation, with a mean of 1.5 copulations per day. Seventy-four percent of the time devoted to incubation was by the female. The incubation period lasted 58 days. Throughout the incubation and early brooding phases the male provided food for the female and the young. Diet consisted of 17 prey items of four vertebrate taxa, mostly mammals, with civet cats (Family Viverridae) and flying lemur (Cynocephalus volans) representing the bulk of the diet.
Received 30 November 2001, accepted 15 August 2003.
The Philippine Eagle (Pithecophaga jefferyi) is one of the most critically endangered birds of prey (Bildstein et al. 1998). It is endemic to the islands of Luzon, Leyte, Samar, and Mindanao of the Philippines. On Mindanao, eagles begin nesting from September to December in habitats ranging from primary lowland forests to highly disturbed woodlands. Recently, efforts were renewed to study the ecology and biology of this highly endangered raptor in an effort to devise management strategies for the long term conservation of the remaining population. An analysis of the eagles' nesting density suggest that there are about 200 pairs in Mindanao, with each breeding pair occupying about 133 km^sup 2^ (Bueser et al. 2003).
A complete breeding cycle in this species lasts two years, and successful pairs produce a single offspring (Gonzales 1968, Kennedy 1985). Since the detailed work by Kennedy (1977, 1985) on Philippine Eagle nesting biology, there have been few studies on the behavior and ecology of this species. Recently, new information on the eagles' breeding success (Miranda et al. 2000) and nesting density and population estimates for Mindanao Island (Bueser et al. 2003) have been published. This study describes the prey as well as the behavior of a pair of Philippine Eagles nesting in a relict forest in Central Mindanao, Philippines. This initial attempt to quantify activity patterns of a pair in an isolated forest habitat is relevant in the light of continued forest fragmentation in...