无锡太湖地区夜鹭及白鹭繁殖生物学研究

1999年 4～ 6月对分布在无锡地区的夜鹭 (Nycticoraxnycticorax)和白鹭 (Egrettagarzetta)的繁殖生物学进行了调查研究 ,调查地面积约 2 72 37 5m2 ,植被以马尾松 (Pinusmassoniana)和香樟树 (Cinnamomumhupehanum)为主。研究结果表明 :栖息地共有鹭巢近万个 ,平均密度为 0 36个 /m2 ,每棵树上平均巢数为1 0 6个 ,最多达 2 5个 /棵树 ;平均窝卵数夜鹭为 3 5 5枚 ,白鹭为 4 89枚 ;平均窝雏数夜鹭为 2 6 8只 ,白鹭为3 96只 ;孵化期白鹭为 1 9～ 2 1天 ,夜鹭为 2 2～ 2 3天 ;孵化成功率白鹭为 84 2 5 % ,夜鹭为 75 46 % ;白鹭雏鸟主要以小型鱼类和虾类为食 ,夜鹭雏鸟主要以鱼类和两栖类为食。

BREEDING BIOLOGY OF NIGHT HERON (Nycticorax nycticorax) AND LITTLE EGRET (Egretta garzetta) IN TAIHU LAKE OF WUXI,CHINA

This paper describes the breeding biology of Little Egret and Night Heron in Yuantouzhu of Taihu Lake.In the research area,the dominant vegetations are Pinus massoniana and Cinnamomum hupehanum ,which are suitable for herons to make their nests.The results showed that there were totally ten thousand nests,the nest density was about 0 36?m -2 and thenumberofnestspertreeinaveragewas1 06.Theave rage clutch size was 3 55 for Night Heron and 4 89 for Little Egret.The average brood size was 2 68 for Night Heron and 3 96 for Little Egret.Incubating time for Little Egret ranged from 19 to 21 days and for Night Heron was from 22 to 23 days.Hatching success was 84 25% for Little Egret and 75 46% for Night Heron.Nestlings of Little Egret fed mainly on small fish and shrimps,nestlingsofNightHeronfedmainlyonfishandamphi bians.