The intermediate egret, median egret, smaller egret, or yellow-billed egret (Ardea intermedia) is a medium-sized heron. Some taxonomists put the species in the genus Egretta or Mesophoyx. It is a resident breeder from east Africa across the Indian subcontinent to Southeast Asia and Australia.
Some authorities classify the intermediate egret in its own monotypic genus, Mesophoyx, while others place it with the smaller egrets in Egretta.
The intermediate egret stalks its prey methodically in shallow coastal or fresh water, including flooded fields. It eats fish, frogs, crustaceans and insects. It often nests in colonies with other herons, usually on platforms of sticks in trees or shrubs. The typical clutch size is 2 or 3 eggs but there can be as many as 6 eggs in a clutch, the colour of the eggs is pale green, with a smooth, slightly pitted shell. Both parents incubate the eggs and they hatch after between 24 and 27 days. The eggs hatch asynchronously, after hatching the adults brood the semialtricial young for 12 days, defending the nests from aerial predators during both incubation and brooding, they crouch over the nest and raise their plumes and point their bill towards the threat. The parenst regurgitate the food to feed the young, initially onto the floor of the nest but later the chick takes the food from the parent's mouth. There may be competition for food within the brood. Pinfeathers may appear on the chicks as early as 4 days old and the young are able to leave the nest at 24 days old, although they return to be fed. Fledging occurs at around 40 days old and they leave the colony after 70 days. In Africa and Australia they are reported to be quite successful breeders with 96% and 88% of nests fledging at least a single chick. Intermediate egret populations are more successful in wet years than in dry years.
No comments:
Post a Comment