Introduction

The Cattle Egret is a gregarious, white, upland ardeid, easily recognized by its foraging association with grazing animals and its exaggerated, head-pumping strut.  Its prediliction for lawns, fields, pastures and grazing animals is quite unlike other native North American herons and egrets which generally feed in or along water and not in close association with livestock. In Britain and Europe, the Cattle Egret is also known as the Buff-backed Heron in reference to the color of its breeding plumes, but in many languages it is simply called Cow Crane, Cow Heron, or Cow Bird, or is named for the wild grazing animal with which it usually associates – e.g., Elephant Bird, Rhinoceros Egret, or Hippopotamus Egret. The Cattle Egret’s Arabic name, Abu Qerdan, means “father of ticks” and refers to the abundance of ticks in Egyptian heronries. Other names involving the word tick, such as Tick Bird, refer to the erroneous belief that Cattle Egrets pick attached ticks from grazing animals; most Cattle Egrets’ prey, however, are insects disturbed by the birds’ grazing activity.

This species began its remarkable worldwide range expansion in the late 1800s, and on the North America continent in the early 1950s; there, in about 40 years, it became common in many regions and is still colonizing new areas. Its rapid, almost worldwide range expansion is well documented and studied, encouraging speculation about those aspects of its life history and ecology that have most promoted growth in range and numbers. Indeed, this unusual bird has provided a rare opportunity for comparative worldwide studies of its population dynamics and its interactions with native colonial waterbirds, as well as with people.

Of particular interest are the economic aspects of the Cattle Egret’s food habits and diet, medical and veterinary concerns, breeding colonies considered to be nuisances, and the species as a bioindicator of environmental conditions. Apparent keys to the spread and success of the Cattle Egret are its dispersal tendencies, gregariousness, diet, foraging adaptability – especially as humans increasingly convert large areas of landscape to pasture for livestock production and to crop fields for rice agriculture – and its breeding adapability and success.  Although many studies of the Cattle Egret have been conducted world-wide, data are lacking for the African subspecies in its original range.