The importance to ardeids of the deep bay fish ponds, Hong Kong

Abstract

This study examines the value of commercial fish ponds around the Deep Bay wetlands, Hong Kong, for herons and egrets. Ardeid use of fish ponds for feeding depends on season, species and age. Winter use was greatest by Cattle Egrets Bulbucus ibis and Little Egrets Egretta garzetta, with up to 100 and 49·3% of the individuals in the study area, respectively, using this habitat. Summer use was highest by Chinese Pond Herons Ardeola bacchus (63·4% of individuals in the study area). The flight lines of Chinese Pond Herons breeding locally revealed that 72% landed around fish ponds. Juvenile Chinese Pond Herons made significantly greater use of fish ponds than adults. Recent fish pond loss due to development is likely to have caused declines in both the number of certain ardeids wintering around Deep Bay, and the number of Little Egrets breeding at a local egretry.