HOME-RANGE AND BIRTH SEASONALITY OF SAGUINUS-NIGRICOLLIS-GRAELLSI IN ECUADORIAN AMAZONIA

A field study of Saguinus nigricollis graellsi in the Cuyabeno Faunal Production Reserve, Ecuadorian Amazonia, established the characteristi cs of the home range and some reproductive aspects of the species. Fie ld data were collected in two climatic seasons: dry, from December 198 9 through March 1990, and rainy, from May through August 1990. Eight g roups visited and/or lived in the study area during the dry season and ten during the rainy season. Group sizes ranged from two to nine indi viduals. Population density was estimated at 22-33 individuals per squ are km. The central group, which was followed intensively, had a home range which included both flooded and non-flooded forests. Terra firme forest was most used by the species. The home range of this group was reduced from 56.2 hectares (ha) in the dry season to 41.7 ha in the r ainy season, probably as a result of a differential distribution of fo od plants between seasons. The presence of dense undergrowth where mon keys could hide to avoid predation and/or a high concentration of food plants seem related to the preferential use of certain areas in the h ome range. The home ranges of neighboring groups overlapped considerab ly and peaceful temporary large groups were frequently observed. A gen eralized birth peak occurred in January 1990, dry season. In June 1990 , rainy season, 40% of the groups exhibited a second birth peak. This reproductive bimodality of S. nigricollis graellsi indicates a high pr oductivity of the forests at the Cuyabeno site. (C) 1995 Wiley-Liss, I nc.