SURVEY OF THE HOWLING MONKEY POPULATION AT LA-PACIFICA - A 7-YEAR FOLLOW-UP

We surveyed the howling monkey population at La Pacifica in Costa Rica over a 1-month period in July and August 1991. The survey method cons isted of an initial 6-day survey, directly comparable to a 1984 survey , and at least two repeat surveys of all areas to locate all groups an d to identify all animals. The initial survey indicated an increase in the number of groups and a decrease in the size of groups from earlie r surveys, though the group composition was unchanged. We used the res ults of initial and repeat surveys to determine population size and co mposition. We located 30 groups with a total of 370 animals. Twenty-on e groups contained animals marked with collars and/or legbands, and fo ur additional groups contained animals with clearly identifiable white markings. Although the population structure has changed over 7 years, it is still within the species-typical range for Alouatta palliata.