Bubulcus ibis

Written by on November 19, 2010 in Bali Bird with 0 Comments

Bubulcus ibis, Cattle Egret, Kuntul Kerbau The Cattle Egret nestBubulcus ibis, Cattle Egret, Kuntul Kerbau s in colonies, which are often, but not always, found around bodies of water. The colonies are usually found in woodlands near lakes or rivers, in swamps, or on small inland or coastal islands, and are sometimes shared with other wetland birds, such as herons, egrets, ibises and cormorants.

The male displays in a tree in the colony, using an range of ritualised behaviours such as shaking a twig and sky-pointing (raising bill vertically upwards),and the pair forms over three or four days. A new mate is chosen in each season and when re-nesting following nest failure. The nest is a small untidy platform of sticks in a tree or shrub constructed by both parents. Sticks are collected by the male and arranged by the female, and stick-stealing is rife. The clutch size can be anywhere from one to five eggs, although three or four is most common. The pale bluish-white eggs are oval-shaped and measure 45 mm x 53 mm. (1.8?2.1 in) Incubation lasts around 23 days, with both sexes sharing incubation duties.The chicks are partly covered with down at hatching, but are not capable of fending for themselves; they become endothermic at 9?12 days and fully feathered in 13?21 days. They begin to leave the nest and climb around at 2 weeks, fledge at 30 days and become independent at around the 45th day.

The Cattle Egret engages in low levels of brood parasitism, and there are a few instances of Cattle Egret eggs being laid in the nests of Snowy Egrets and Little Blue Herons, although these eggs seldom hatch.[19] There is also evidence of low levels of intraspecific brood parasitism, with females laying eggs in the nests of other Cattle Egrets. As much as 30% extra-pair copulations have been noted.

The dominant factor in nesting mortality is starvation. Sibling rivalry can be intense, and in South Africa third and fourth chicks inevitably starve.In the dryer habitats with fewer amphibians the diet may lack sufficient vertebrate content and may cause bone abnormalities in growing chicks due to calcium deficiency.


The Cattle Egret feeds on a wide range of prey, particularly insects, especially grasshoppers, crickets, flies, and moths, as well as spiders, frogs, and earthworms.In a rare instance they have been observed foraging along the branches of a Banyan tree for ripe figs.The species is usually found with cattle and other large grazing and browsing animals, and catches small creatures disturbed by the mammals. Studies have shown that Cattle Egret foraging success is much higher when foraging near a large animal than when feeding singly.When foraging with cattle, it has been shown to be 3.6 times more successful in capturing prey than when foraging alone. Its performance is similar when it follows farm machinery, but it is forced to move more.

A Cattle Egret will weakly defend the area around a grazing animal against others of the same species, but if the area is swamped by egrets it will give up and continue foraging elsewhere. Where numerous large animals are present, Cattle Egrets selectively forage around species that move at around 5?15 steps per minute, avoiding faster and slower moving herds; in Africa, Cattle Egrets selectively foraged behind Plains Zebras, Waterbuck, Blue Wildebeest and Cape Buffalo.Dominant birds feed nearest to the host, and obtain more food.

The Cattle Egret may also show versatility in its diet. On islands with seabird colonies, it will prey on the eggs and chicks of terns and other seabirds.During migration it has also been reported to eat exhausted migrating landbirds. Birds of the Seychelles race also indulge in some kleptoparasitism, chasing the chicks of Sooty Terns and forcing them to disgorge food.


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