Abstract: Characteristics of Four Herons living in Yuant ouzhu of Wuxi in the Taihu Lake region were studied in 2000.Results showed that there were 36 400 nests of Four Herons in Yuantouzhu,averaging about 0.52 nest/m ²,and 3.36 nests per tree in the habitat.Earlier settlers often built their ne sts in relatively better locations,far away from villages and highways.Tall tree s,especially Pinus massoniana,were their favorite nesting ground,often with larger birds on top or in the middle of the canopy and the smaller in the lower part.The average size of a clutch was 3 for Nycticorax nycticorax and Bubu lcus ibis,and 5 for Egretta garzetta and Ardeola bacchus.