Friday, July 9, 2010

Animal Facts - Cattle Egret

By Marina K. Villatoro

The Cattle Egret is a cosmopolitan species of heron. These guys are found all over Central America and in Costa rica they can be found in the Manuel Antonio National Park. The non-breeding adult has mainly white feathers, a yellow bill and grayish-yellow legs. During the breeding season, adults of the western subspecies develop orange-buff plumes on the back, breast and crown.

The Cattle Egret feeds on a wide range of prey, particularly insects like grasshoppers, crickets, flies, and moths, as well as spiders, frogs, and earthworms. In rare cases they have been seen foraging along the branches of a Banyan tree for ripe figs. They have an 88-96 cm wingspan and 46-56 centimeters in length. Life span in the wild is unknown. Cattle egrets at Woodland Park Zoo have lived more than 10 years.

The male displays in a tree in the colony, using a range of ritualized behaviors such as shaking a twig and raising bill vertically upwards and three or four days later he gets a couple. They choose a new mate every season. The cattle egrets' daily routine is to leave their roost at dawn to seek food, flying in long, crooked lines, which allows easy identification of the species. As night approaches, they return to their roost.

Some populations of the Cattle Egret are migratory but others only show post-breeding dispersal. The Cattle Egret nests in colonies, which are often, but not always, found around bodies of water. The female lays one to five eggs, although three is most common. The eggs are pale bluish-white. Incubation lasts around 23 days, with both sexes sharing incubation duties. The chicks are 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.

They can be found in the tropics, subtropics and warm temperate zones from Central America. Its global population estimated to be 3.8-6.7 million individuals. For these reasons, the species is in the Least Concern group. On the other hand the expansion and establishment of the species over large ranges has led it to be classed as an invasive species.

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