Research On The Population Of Reed Parrotbill (Paradoxornis Heudei) During The Winter In Chongming Dongtan, Shanghai

From November 2008 to March 2009, an ecological investigation on the population of Reed Parrotbill(Paradoxornis heudei) during winter was conducted in Chongming Dongtan, Shanghai. During the study, an analysis about the variation of the habitat of Reed Parrotbill population was undertaken, and also a correlated analysis on the relationship between Reed Parrotbill population and its environmental factors was done. One-ANOVA was used to analyze the density, distribution of Reed Parrotbill population in winter and the impacts of Cordgrass invasion and reed harvesting to the reedbed. Multi-regression was used to analyze the relationship between the density, distribution of Reed Parrotbill and environmental factors. And meanwhile, Habitat Selection Index Model was used to estimate the foraging habitat of Reed Parrotbill population in winter. The results showed:1. Reed Parrotbill was observed in reedbed mostly. In Chongming Dongtan, the density was in average 5.08±3.11ind/hm2; the density and distribution had significant differences in different habitats. The density in High Reed Sample was 8.4 ind/hm2 and 0.6 ind/hm2 in Cordgrass Sample. The density had significant difference between Cordgrass-reed mixed Sample and reed samples, and a significant difference between harvested sample and non-harvested samples.Reed Parrotbill lived in group in winter, and group amount decreased when group size was larger, mostly 2～3 individuals per group. The group size in different habitat had no significant difference. Only one group was observed in Cordgrass Sample.2. Reed harvesting and Cordgrass invision had important impacts on reedbed. Vegetation statistics had significant differences between samples. Therefore, the distribution, foraging behavior and foraging efficiency had extremely significant differences between different habitats. In mixed sample, the density of Reed Parrotbill was lower than in harvested sample, but the proportion of reed with foraging marks was higher. It meant, in mixed area cordgrass limited the activity space and food resource of Reed Parrotbill, the density of Reed Parrotbill might approach the carrying capacity.3. Multi-regression result showed, the reed diameter positively correlated with density of Reed Parrotbill, the reed height and density had significantly positive impacts and food resource hold a positive impact to the distribution of Reed Parrotbill; smooth cordgrass had a negative impact to both density and the bird distribution. The habitat quality of Reed Parrotbill was on the decline due to the smooth cordgarss invasion and reed harvesting. The group size of Reed Parrotbill in Chongming Dongtan was on the decline. Cordgrass was not suitable for Reed Parrotbill.According to the result of HSI analysis, the suitability of foraging habitats for Reed Parrotbill was:High Reed>Harvested Reed>Mixed Area>Low Reed.