Effects of Human Disturbance on Foraging Behavior of Dunlins Calidris alpina

Studies on effects of human activity on the foraging behavior of dunlins Calidris alpina were conducted using methods of focal-animal sampling and human-disturbance experiment at the beaches of Yanpen and Yuecheng, Yueqing bay in Zhejiang Province from November 2003 to March 2004. Results of focal-animal sampling showed that 96.6% of dunlins responded to human disturbances at a distance of 35 m or less by either running or flying. Dunlins spent 90% (94% in Yanpen with less people while only 85% in Yuecheng with more people) of the time foraging and 10% avoiding human disturbance generally. Number of persons and type of human activities had significant effects on foraging time, respectively. The distance and frequency of dunlin moved, and the response behaviors of dunlin to human approaching were significantly sensitive to the number of persons, the type of human activities and the distance from humans. The results of human-disturbance experiment indicated that the distances of dunlins responding to human were 3-30 m. The minimal approach distance to dunlins was significantly lager at one disturber than that at two disturbers, but no significant difference between two types of human activities, walking and running. This study tested the hypothesis that the human activities in shorebird foraging areas adversely affect the foraging behavior of dunlins.