4种鹭的繁殖生态

1999-2001年对池鹭、牛背鹭、白鹭、夜鹭混群的迁入状况、繁殖行为、雏鸟生长等进行了观察研究。结果表明：鹭鸟数量逐年增多，种类由2种增加到4种，4种鹭鸟在筑巢、取食和生活习性等方面具有一定的种群协调性。4种鹭鸟的食物组成存在一定差异。夜鹭以蛙类和鱼类为主；白鹭以鱼类和甲壳类为主，另有蛙类和昆虫类；牛背鹭的食物主要由昆虫类和蛙类组成；池鹭以鱼类为主。幼鸟体重生长率与成体体型大小成负相关，比较分析4种鹭鸟体重增长曲线，以池鹭和牛背鹭生长较快。

Breeding Ecology of the Four Herons

The breeding ecology of the four herons (Ardeola bacchus, Bubulcus ibis, Egretta garzetta, Nycticorax nycticorax), such as ingression time, breeding behavior and nestling growth were observed and studied from 1999 to 2001. The results indicate that the numbers of herons are increasing every year. The species of heron were raised from two to four in this region. The community of four heron can build nests, look for food and live with its habits in harmony of population. The four heron differ partly in food components. The food components of Black-crowned Night Heron chiefly consist of frog and fish. Those of Little Egret are mainly composed of fish and crustacean. Cattle Egret live on insects and frog, Chinese Pond Heron on fish. There is a negative correlation between the weight growth and the adult size of the four young of heron. Analysis of the growth curve shows that Chinese Pond Heron and Cattle Egret have faster growth rate than the other two.