Student Prize Award Abstract
2001 Oral Paper Honorable Mention
IMMIGRATION PATTERNS AND GROUP STABILITY IN WILD GOLDEN-HEADED LION TAMARINS IN SOUTHERN BAHIA, BRAZIL
B. Raboy and J. Dietz University of Maryland, Dept of Biology, College Park, MD, 20742, USA
The extent of group stability in the Callitrichidae remains unclear. While some studies suggest callitrichid groups consist of mainly unrelated individuals resulting from high immigration rates, others indicate much lower rates of dispersal and suggest that recruitment takes place from births. We studied population dynamics in 7 groups of golden-headed lion tamarins (Leontopithecus chrysomelas; GHLTs) for periods of 3 months to 6 years at Una Biological Reserve, Southern Bahia, Brazil. Both high and low levels of immigration were documented depending on the years under scrutiny. The four longest-studied groups demonstrated periods of stability from 2 to 4.5 years, increasing only from new births. Stable periods were followed by turnover periods marked by high rates of disappearance and immigration. During these transitional periods we also saw the creation of new groups. Thus we suggest that groups alternate between stable and unstable periods and that the recruitment strategies in GHLTs vary accordingly. Smaller and newly formed groups were more inclined to accept immigrants. In 11 of the 15 cases, immigrants entered groups with only two individuals, however, no immigrations occurred in groups larger than 4. Males entered groups with breeding vacancies, aggressively displaced resident breeding males or entered groups as subordinates. However, females only entered groups that lacked breeding females. Evidence suggests that these periods of instability occur simultaneously in neighboring groups.