Partial completion of a census of the western lowland gorilla (Gorilla g. gorilla (Savage and Wyman)) in southwestern Central African Republic

Abstract

In June through August of 1986 I completed a census of the southern extreme of the gorilla range in the Central African Republic. Two 100 km2 blocks (214.4 km of transects) of mostly primary forest along the Sangha River were surveyed. In the first block a total of 220 nests were counted and in the second 327. The average gorilla density for both blocks was calculated to be 1.6 gorillas per km2. The second block contained almost twice the density as the first with 20 gorillas/km2 as opposed to 1.1 gorillas/km2. The average nest group size overall was 4.1 nests with the first block having a slightly larger average nest group size of 4.3 as opposed to 3.9 for the second block. The most common nest material was Megaphrynium macrostachyum. The seeds of at least one of three important fruits eaten by gorillas were found in more than 65% of the droppings analyzed, indicating a high level of frugivory in the wet season diet of western lowland gorillas. Nine other species of diurnal primates were also observed during the survey.