Choice of analytical method can have dramatic effects on primate home range estimates

Primate home range sizes can vary tremendously as a consequence of the analytical technique chosen to estimate home range. This is exemplified by a recent dataset on free ranging snub-nosed monkeys (Rhinopithecus bieti)in Northwest Yunnan, China. Our findings show that the grid cell method cannot substitute for the minimum convex polygon (MCP) method and vice versa. MCP-based estimates are far too large, especially when the form of the home range is irregular due to forays into peripheral areas. Here, we propose an adjusted polygon method, whereby unsuitable and never visited areas are clipped out from the polygon, thus producing more accurate results. Compared to the grid cell method, the adjusted MCP is much more robust when the number of group relocations is limited; MCP turned out to be the method of choice for calculation of monthly and seasonal home ranges. The grid cell method on the other hand yielded the most precise estimates for total or annual home ranges. The style of ranging exhibited by a given primate taxon or population determines which analytical procedures should be applied to estimate home range size, and we would stress the need for thorough evaluation of the pros and cons of home range estimators before conducting field work and analysing data

Translocation and radiotelemetry monitoring of black-tailed marmosets, Callithrix (Mico) melanura(É. Geoffroy in Humboldt), in a wildlife rescue operation in Brazil

Five black-tailed marmoset Callithrix (Mico) melanura (Primates - Callitrichidae) individuals were monitored by radiotelemetry as part of a project on translocated wildlife affected by flooding the Manso River reservoir in the state of Mato Grosso, western Brazil (14° 52' S and 55° 48' W). The animals were monitored for eight months from October 2000 through August 2001. Only one death was recorded among the translocated animals. Two pairs established their home ranges in the new area, after some exploratory behavior. The new home range sizes varied from 0.72 to 4.27 km². The home ranges of male and female overlapped in the case of both pairs by 0.59 to 2.30 km². Trips were always made in pairs and not individually. The results indicate the feasibility of a successful translocation program for this species, as long as the animals are translocated to a similar habitat nearby