The crested ibis (Nipponia nippon) is one of the most endangered species in the world. There is only one wild population, about 200 individuals, distributing in Yangxian County of Shaanxi Province, China. From May 2000 to February 2002, we investigated the activity, foraging behaviors, home range and habitat utilization of the crested ibis in the breeding period. We observed the wild ibises with ×20-60 telescope and identified the individuals by the colour / numbered bands on their legs. All nest sites, roost sites and forage sites were located using a Global Position System (GPS). Data on the locations, habitat topography, rivers and streams, roads, residential areas and stone mines were all imported into the ArcView GIS. MPC and fixed Kernel methods were used to calculate the home ranges.
The average foraging distance of the crested ibis was different in wintering, breeding and late breeding periods, which was 2.821±1.488 km, 0.563±0.681km and 1.706±0.834 km, respectively. In the same period of time, the foraging distance showed no significant difference among birds, and in the two research years, there was no difference between the same wintering and breeding periods. However, because of drought in 2001, the foraging distance in the late breeding period was significantly different from that in 2000. The ibises went to the furthest foraging sites at 10:00 - 12:00 and 16:00 - 18:00, and they foraged at the nearest site at 06:00 - 08:00. The Crested ibis showed different foraging behaviors at different times of day. They foraged frequently from 06:00-10:00 and 16:00-18:00, and spent more time resting and preening at noon and dusk. On the study of home range, totally eight birds were investigated and located continuously. According to MCP and 90% Kernel methods, average home range sizes were 100.9±49.8 hm2 and 175.6±91.3 hm2, respectively. The core area of home range was 43.8±21.5 hm2 by 50% Kernel. The home ranges between individuals were highly overlapped (24.5±27.3 %). Crested ibis tend to breed in colonies and there were no remarkable difference between paired birds and other individuals in home range overlaps. The habitat utilization analysis indicated that, the utilization of conifer-broadleaf forest was significantly lower than its availability, while the utilization of paddy fields was significantly higher[Acta Zoologica Sinica 49 (6): 755 - 763 , 2003].