关键词: 覆盖物, 间接捕食风险, 高原鼠兔, 栖息地利用

Abstract: The influence of cover on habitat utilization of plateau pikas (Ochotona curzoniae) were studied. The work was carried out at the bird-island area of Qinghai province, the People's Republic of China from May to August1994. The cover was manipulated by placement of small boards in the area where the pika inhabited in. Habitat utilization was responsive to change in the cover treatments. The pika either increased burrow utilization and decreased microhabitat utilization, or shifted into a safe microhabitat that was not treated with the boards. On the other hand, foraging behaviors were also affected by the treatments. The time spent on feeding was significantly decreased, however, the time spent on vigilance was significantly increased. In addition, feeding rang was shrunk by feeding close to the hole of the burrow as possible. These results suggest that the cover is not a refuge, but only a source of indirect predation risk for the pika. The pika possenses the ability to assess the risk of be preyed upon. The behavioral change in habitat utilization in fact .is a behavioral decision made b y the pika based on trade off energy gain against risk of predation. Predation risk is not only an important factor that they decide where to feed, but also an important foraging cost.

Key words: Cover, Indirect predation risk, Plateau pika(Ochotona curzoniae), Habitat utilization