BREEDING ECOLOGY AND BIOLOGY OF FOUR SPECIES OF EGRET AND HERON
四种鹭类繁殖生态生物学研究

rom 1988 to 1989, observations on the breeding ecology and biology of four species ofegret and heron(Nycticornx nyticorax ,Egretta garzetta,E. eulophotes,Ardeola bacchus)havebeen taken in the Dongzhai bird conservation ,Henan province. The results are as following:E.eulophotes is a new record in south Henan province, breeding in this region for thefirst time.The four species of egret and heron are breeding in harmony of nested seat,nurture andaction in the same area. Most of N. nyticorax use the old nests,these seates are advanta-geous. Only fewer of E. garzetta and E.eulophotes use the old nestes.A. bacchus build theirnew nestes each and most of their nestes seating on the edge of the nest area. The nestes ofthese species are simple,dash-shapped.The size of nestes are varied depending on the size ofthe branches. Generally,its size is 30-45 outside ,20-30 inside,8-35 in depth and 12-25cm in height.Feeding habit of young birds:N. nyticorax feeds mainly on frongs and auxiliarily on littleloaches.E.garzetta feeds mainly on loaches and auxiliarily on small wild fishes.A. bacchusfeeds mainly on loaches and auxiliarily on frogs.E. eulophotes feeds only on loaches.The young birds of E. garzetta need about twenty days to pretect themself from beingcatched by man and easily escaped form one branch to another branch of tree.N. nyticoraxand E. eulophotes need twenty-two days.A. bacchus needs fifteen days. The growth rate of A.bacchus and E. garzetta is higher than N. nyticorax and E.eulophotes.When young birds ofthese four species leave their nestes,the length of their wings are nearly the same as theadult.The major breeding damage of egret and heron are disgusting weather in this region.