The Great Bustard Breeding Season, Habitat, And Endangered Mechanism

We studied the nest-site selection,community structure of birds.endangered mechanism and protecting strategy of the Great Bustard during the breeding season on its traditional breeding areas.the Bei-da-gang the southeast Ke-you-qian-qi that locate on the boundary of northwest Jilin province and Inner Mongolia municipality between 1999 and 2001,the main results are as following:1. The habitats for moving about of Great Bustard are hillocks on grassland.and they prefer to move about on the valleies of grassland during their breeding season.There are 4 main vegetation characteristic factors that determine the nest-site selection,the factors are the vegetation canopy,vegetation density,food and the height of plant.The Great Bustard selects the areas with higher vegetation canopy,vegetation density,plant species and insect quantity.most height of plants are below 20cm,but we also found they move about in tall grass occasionally.2. I put foreward the concept gathering display field for the first time,and found that fire influences the gathering display field selection of Great bustard to a certainty. The Great Bustard selects the areas with abundant plant species.higher vegetative cover score.smaller proportion of bare area and taller plants to display on postfire grasslands;the important factors that influence the Great Bustard to selection display fields are the proportion of hay, Stipa baicalensis density and the thickness of hay on unburing grassland.3. The Great Bustard is big-sized bird that build nest on the ground and the nests distribute in sparse group.most of their nests locate on the middle slope of hillocks,especially on the southern middle slopes towards to the sun,the biggest gradient is not more than 8?,the most important 3 factors that determine nest-site selection are height of plant.density and thickness of hay.4. The Great Bustard is polyphagia bird,but it feeds mainly on plants.The feeding field habitat selection relate with that whether the grassland burn or not last year.The important factors that determine the feeding field selection are the plant species,vegetative cover score.density Hemerrocallis minor and the density of Pedacularis sp.on burning grasslandsjthe density of vegetation.insects quanlity.plant species richness and the height of plant are the main factors that determine the feeding field selection on unburning grasslands.5. The breeding areas of Great Bustard is Stipa baicalensis grassland,the community structure of birds on it is complicated.We found breeding birds 19 species,11 species are familiar birds.The species diversity index is 2.23,the uniformity index is 0.82,the species are more abundant than that of Inner Mongolia tapicalgrassland.6. The population quantity of orient subspecies of Great Bustard only is 500 to 800 individuals.and the distribution takes on obvious island isolation,!! is typical endangered species.According to the observation in field and analyse we discuss the endangered mechanism from the inner factors and outer factors theoreticly.and put foreward relevant protecting strategies.