Video credit: Manuel Cano Alfaro (Guatemala)
Review: Abdel Rahman El Gamal
This video was taken at Lake Peten Itzá, Guatemala
Introduction: Great Egret, Ardea alba (ex Casmerodius albus) has several common names including common egret, large Egret, White Egret, Large Egret, Great White Egret, and Great American Egret.
Description: Great Egret adults are entirely white bird whose neck and legs are thin and long, with orange-yellow bill, green facial skin and bare blackish legs and feet. The bird has a distinct kink on the upper neck. In the breeding season, the bird develops long delicate plumes on its back which extend about ten centimetres or more beyond the tail. For other times of the year, the bird loses its plumes. Males and females of the Great Egrets are alike. The average weight of an adult bird ranges from 0.7 – 1.5 kg with length 80-104 cm, and 130-170 cm for wingspan.
Distribution and Habitats: The species inhabits all kinds of aquatic systems throughout the world including and depending on locations river margins, lakes shores, marshes, flood-plains, rice-fields, coastal wetlands, aquaculture ponds, and others. In general, the great egrets are distributed across most of the tropical and warmer temperate regions of the world. They migrate from cold weather to winter in North Africa, India, Southeast Asia, South America, Australia, New Zealand or warmer locations within the same country.
Feeding behavior: Great Egrets are often observed wading in shallow water (fresh or salt), hunting and catching their prey that pass by the bird. They mainly feed on fish, but they may also feed on crustaceans, aquatic insects and small vertebrates such as amphibians. In drier habitats, the bird may eat terrestrial insects, lizards, small birds and even mice. Great egrets are diurnal feeders but are most active at dawn and dusk. They may feed solitarily or in small groups of 10-50 individuals. However, they may form flocks of hundreds where food is abundant.
Reproduction: The breeding season varies according to geographical location whereas the birds in the temperate zone breed during spring and summer while in the tropics, they may breed during the rainy season when the food supply is more abundant. Often, the bird breeds in colonies of tens, hundreds or even a thousand pairs. The breeding birds mate in their nests that are constructed from sticks and vegetation and placed above ground or water surface at a height of about 5-12 m in sites that are protected from ground predators. Building of the mating nest is the responsibility of the male. A female egret lays a clutch of eggs that consists of three to four eggs that are incubated by both parents for about 23 to 26 days. Hatched young are fed by regurgitation. They usually leave the nest 30 to 42 days after hatching where they remain dependent on their parents for some time afterwards.
Threats and conservation: The major threat occurred to the bird populations was during the late 1800s and early 1900s, when egret plumes were in great demand for decorating women’s hats and dresses. Knowing that one kilogram of plume is produced by killing 300 birds which indicates the large numbers of the birds that were killed for decorating ladies hats and dresses. Luckily and before reaching close the extinction level of the great egret, the bird lovers, who formed the Audubon Society, were able in 1901 to get legislation enacted to ban the feather trade and hence to stop the bird slaughtering.
The loss and degradation of habitats and the illegal collection of eggs and chicks by local peoples are added the threats which are sporadically practiced in some places.
However, because the bird has an extremely large range, its population size is very large, and since the decrease in its populations –if occurs- is not the rapid, hence the bird population are not neither vulnerable nor threatened in the present.