| group size effects on foraging and vigilance in migratory tibetan antelope. | large group sizes have been hypothesized to decrease predation risk and increase food competition. we investigated group size effects on vigilance and foraging behaviour during the migratory period in female tibetan antelope pantholops hodgsoni, in the kekexili nature reserve of qinghai province, china. during june to august, adult female antelope and yearling females gather in large migratory groups and cross the qinghai-tibet highway to calving grounds within the nature reserve and return to q ... | 2007 | 17582704 |