Study On The Wintering Cluster And Habitat Characteristics Of Great Bustard (Otis Tarda Dybowskii) In The Yellow River Wetland

The Great Bustard (Otis tarda) is an endangered species with the status of national first-class protected wild animal of China. The Eastern subspecies, Otis tarda dybowskil, reproduces in Northeastern China and Inner Mongolia, and overwinters mainly in the Yellow River and Yangtze River basins. Many avian migratory routes, including that of the Great Bustard, pass through the Eastern Henan Yellow River wetland. In two consecutive winters (2009-2010, 2010-2011), we investigated O. tarda dybowskil flocks in the Eastern Henan Yellow River wetland, recording population sizes, flock characteristics, and habitat preferences. The results are as follows:1)53 flock occurrences and 2026 individual occurrences were recorded; on average each flock contained 38.23 individuals, including 10.13 mature males. Flock sizes peaked in November and December, then remained high and relatively stable through January and February. As spring approached in March and April, the flocks shrank markedly, then eventually moved off. O. tarda dybowskil population size and flock number did not change significantly between the 2 winters studied.2)We identified 5 O. tarda dybowskil overwintering habitats, 3 of which showed relatively high O. tarda dybowskil concentrations. There did not appear to be significant correlations between flock number and habitat area. Flock size however was positively correlated with habitat area. O. tarda dybowskil distribution was heavily influenced by riparian zone characteristics and human activities.3)Most O. tarda dybowskil flocks were small and medium in size. Of the flocks observed, 81.14% had less than 60 individuals and 37.74% had no more than 30 individuals.4)O. tarda dybowskil individuals would scatter while foraging for food, and concentrate at noon to rest in areas affording reasonably good concealment. If lightly disturbed, the birds would take short flight at altitudes of 10-20 meters, with no discernible formations. Greatly alarmed birds or birds moving away from the habitats flew long distances in W-shaped formations.5)We recorded 10 habitat factors in 52 quadrants, analysis of the data showed that the overwintering Great Bustards preferred habitats with the following characteristics: (1) high wheat seedling density; (2) wide field of vision, undulating riparian land; (3) at least 2000m from the nearest village, at least 500m from the nearest road/stand of trees/hydroelectric facilities.