Cattle Egret


ORDER: Ciconiiformes

FAMILY: Ardeidae

GENUS: Bulbulcus

SPECIES: ibis

DESCRIPTION:
Small, stocky, (about 20 inches long, wing span 35 inches) short-necked white species with short, stout yellow-orange bill. During breeding season there is a crest of orange erectile feathers on crown and nape, and orange ornamental feathers on upper chest and back and more vivid coloring of bill (orange to coral red), eyes and feet. It is more thick set than the Little Egret and has a more hunched appearance. The sexes are similar. Voice is silent outside nesting or roosting sites: a low-pitched and agitated "kwark."

GEOGRAPHICAL RANGE AND HABITAT:
Wet fields, marshes, swamps, pastures, grassland, often associated with large grazing mammals such as elephant, buffalo, eland, zebra or domestic stock. Almost world wide distribution. They have migrated in historic time from Africa to the Americas, South East Asia and the Malay Archipelago as well as the Australasian region and Oceania.

DIET:
Feed on cryptic prey that are forced into showing themselves when flushed by grazing mammals. Grasshoppers are an important item in their food which also includes toads, tree-frogs, skinks, dragon flies, beetles, crickets, moths, termites and spiders. They are thought to feed on blood-sucking parasites of the larger hoofed mammals and are often seen riding on their backs, but it seems more likely that they are feeding on the insects stirred up. Cattle Egrets eat only a few ticks, and these are mainly engorged and recently dropped, rather than picked from the host.

LIFE CYCLE/SOCIAL STRUCTURE:
They are communal birds, both in and out of breeding season, in groups of 5 to 30. After a day of feeding amongst grazing cattle they can be seen to congregate in groups of 10 to 200 during the evening and then fly in V-formation to their roosting sites, usually near water, which may be some distance away. Nesting colonies are built either on their own or in association with other herons and egret species, usually near water in dense reed beds or other marshy sites. Nest of twigs, branches, and reeds is built 6 to 12 feet above ground in trees or shrubs. Congregation and close density of birds seems to be a significant factor in providing the necessary stimulus for breeding, sufficient rain being a prerequisite for its success. One to three bluish eggs are laid at intervals of 48 hours, incubation by both sexes starting with the first egg, which hatches after 3-4 weeks. The parents protect their young, providing shade with their wings during the hot part of the day.

SPECIAL ADAPTATIONS:
Adaptability to presence of human agriculture. Watch as they feed on flies; they do a peculiar head-quiver before they strike. Perhaps it helps them precisely gauge the prey's distance.

INTERPRETIVE INFORMATION:
They have colonized other areas of the world only in the last 40 or 50 years. The question is, why not sooner. The increase in human populations and attendant increase in cattle herds, may have been a significant factor. It was the spread and population expansion of the cattle egret in its African homeland that preceded the great leap to South America a hundred years ago. With the demise of the rain forests in the last 50 years, barriers to northern migration were removed. The first cattle egrets arrived in the U.S. in 1952. An equally dramatic expansion has occurred in Asia. Also known as Buff-backed Heron, as well as by a number of common names in North America: Cow Crane, Cow Heron, Cow Bird, Tick Bird, Tick Heron. The Arabic name, Abu Qerdan, means "Father of Ticks."

OUR ANIMALS:

STATUS IN WILD:
In no danger, in fact, dramatically increasing in range and numbers. However they are on Appendix III of CITES (listed as threatened by a specific country).

BIBLIOGRAPHY:

  1. Hancock, James. 1978. "Spectacular Spread of the Cattle Egret" in Wildlife.
  2. Karmali, John. 1980. Birds of Africa. Viking Press, N.Y.
  3. Langrand, Oliver. 1990. Guide to the Birds of Madagascar. Yale University Press
  4. Pratt, H, P. Bruner & D. Berrett. 1987. A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press.
  5. Sibley, Charles & Burt Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the World.
  6. Telfair, Raymond Clark II. 1983. The Cattle Egret: A Texas Focus and World View. The Texas Agricultural Experiment Station.

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