Mr. Clarke et El. Zucker, SURVEY OF THE HOWLING MONKEY POPULATION AT LA-PACIFICA - A 7-YEAR FOLLOW-UP, International journal of primatology, 15(1), 1994, pp. 61-73
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.