Abstract # 53:

Scheduled for Thursday, June 21, 2007 05:00 PM-07:00 PM: Session 7 (South Main Hall) Poster Presentation

Survey of the Howler Population of La Pacifica, 2006.

M. R. Clarke1,2,3, R. Ford1, D. Arden3 and K. E. Glander1
1Duke University, Durham, North Carolina 27708, USA, 2Univ. of New Orleans, 3Tulane University
     We surveyed the population of Howlers (Alouatta palliata) on Hacienda La Pacifica in July 2006. We completed a single pass of the farm in a manner similar to a 1984 survey, and to the first pass of surveys conducted in 1991 and 1998. Our results revealed a population of 202 group-living animals plus 2 male solitaries. There were 38 adult males, 98 adult females, and 66 immature animals in 16 social groups. Mean group size was 12.6 (range=4-26) and the adult male to female ratio was 1:2.6. These results were remarkably similar to the results from 1974-76 and our previous first pass surveys. The trend toward increased numbers of smaller groups observed in 1991 and 1998 following the original change in land management appears to be reversing. The transition from wet rice agriculture to tilapia tank farming was completed in 2004, and there have been minimal disturbances in land use since that time. Larger groups were found in undisturbed forest and in strip forests that were returned to irrigated cattle pasture in 1999. Fewer groups were found in the strips of forest around the tilapia tanks, which are now populated with large water birds. These results suggest that the population is re-stabilizing, but a subsequent survey will be necessary to substantiate that trend. Supported by an ASP Conservation Grant and a Duke A&S Grant to KEG.