Habitat Selection Of Black-crowned Night Heron (Nycticorax Nycticorax) In Breeding Period In Momoge Nature Reserve In China

2006-2007,in Momoge Nature Reserve,through the fixed-spot observation,GPS positioning,plot sampling and line sampling,investigation of the overall number and factors measurement,as well as t-test,F-test,factor analysis,the structure of the nest area,spatial pattern of nests and different breeding stages of foraging habitat selection of Black-crowned Night Heron(Nycticorax nycticorax)was studied.The results are as follows:(1)In the Nature Reserve,nesting habitats of Black-crowned Night Heron are simple,they nest only in the artificial poplars,which have age of 31 years,average height of 21.39 m,diameter of 20.94 cm,density of 0.128 trees/m~2,the distance from water of 173 m and the altitude of 142 m.Their nests are 43.25cm in outer diameter and 23.95 cm in inner diameter,44.25 cm high and 11.32 cm deep.The nest materials are 32.34 cm in length and 0.38 cm in diameter.(2)By measuring 113 nests,we know that their nests space generally in 2-4 m. Only one nest in one tree takes 50.09%,most of which is on the main branches.Two nests in one tree take 44.6%.The nests on poplar are 18-19 m high in general.The nest diffusion coefficient is C=1.67＞1,subject to the distribution of the nest clumped dispersion.(3)Their breeding season can be generally divided into three stages:nesting period,incubation period and fostering period.In the nesting period,the foraging habitat factor survey contains three principal components:food,water and hidden factors.Through the T-test on the feeding habitat of black-crowned night herons and foraging habitat factors of random plot sampled,it is concluded that vegetation cover and water depth are of significant differences.In the incubation period,foraging habitat factor survey contains four principal components:food,water,plant and hidden factors.Through the T-test on the feeding habitat of black-crowned night herons and foraging habitat factors of random plot sampled,it is concluded that reed density and water depth are of significant differences.In the fostering period,foraging habitat factor survey contains four principal components:food,water,plant and hidden factors.Through the T-test on the feeding habitat of black-crowned night herons and foraging habitat factors of random plot sampled,it is concluded that vegetation density and water depth are of significant differences.Through the comparison of feeding habitat factors based on nesting period, incubation period and brood period,we arrive at a conclusion that the main factor for the feeding habitat selection of black-crowned night herons is water depth.