Birds
Cattle Egret
Bubulcus ibis · also called buff-backed heron, cow crane
The small white bird standing on a cow’s back, or marching through a pasture beside a herd, is a cattle egret. A century and a half ago it lived only in Africa and Asia. It has since spread, under its own power, to most of the warm world.
Overview
Bubulcus ibis is a small, stocky white heron that feeds in dry pasture and fields rather than water. It follows cattle, buffalo, elephants, and tractors, catching the grasshoppers, flies, frogs, and lizards they flush from the grass.
The self-made global bird
Native to Africa and southern Asia, it flew across the Atlantic to South America around 1877, spread through the Americas, reached North America by the 1950s, and also colonised Australia — one of the fastest natural range expansions of any bird, and it was never introduced by people.
Breeding dress
Usually all white with a yellow bill, in the breeding season it grows golden-buff plumes on the head, back, and chest. It nests in dense mixed heron colonies over water.
Status
Least Concern and still increasing, one of the most successful herons in the world, helped everywhere by the spread of cattle ranching.
Cattle Egret: common questions
How did the cattle egret spread around the world on its own?
It appears to have done it by flying, helped by weather. Cattle egrets are strong fliers and are known to be carried long distances by storms and trade winds, and the species has a habit of dispersing widely when populations are high. The generally accepted account is that birds from West Africa crossed the Atlantic to northeastern South America in the late 1800s, first being recorded there around 1877, established themselves, and then spread north and south through the Americas over the following decades as ranching created ideal habitat. It reached Florida in the 1940s and had colonised much of North America by the 1960s. It also spread independently into Australia and across the Pacific. Unlike the starling or the house sparrow, it was never deliberately introduced anywhere.
What is the cattle egret doing with the cattle?
It is using the large animal as a beater. As a cow, buffalo, or elephant walks and grazes through grass, it flushes out grasshoppers, crickets, flies, frogs, and other small animals, and the egret walks alongside or just behind it, or perches on its back, snapping up the prey as it breaks cover. Studies have shown that a cattle egret feeding with livestock catches roughly one and a half to two times as much food, with far fewer steps and pecks, as one feeding without a large animal nearby. The birds will follow tractors and other machinery for the same reason, and in Africa they follow wild grazers and even army-ant swarms.
Is a cattle egret the same as other white egrets?
No, though they can look alike at a distance. The cattle egret is smaller and stockier than the great egret or the snowy egret, with a shorter, thicker neck often held in a hunched jowl, a shorter yellow bill, and a rounder head. It is usually seen away from water, in dry pasture and fields, whereas the great and snowy egrets hunt fish and other aquatic prey by wading. In breeding plumage the cattle egret shows warm golden-buff patches on the head, back, and breast, which the pure-white great and snowy egrets never do.
Are cattle egrets good or bad for farms?
On balance they are considered beneficial to livestock farming. They eat large numbers of pasture insects, including grasshoppers and crop pests, remove flies and, to a lesser extent, ticks and other parasites from around and on the animals, and they do not damage crops. The main downsides are the noise, smell, and mess of a large breeding colony if it forms near houses, and the serious aircraft-strike risk when big flocks commute past an airport, which sometimes leads to colonies near airfields being dispersed.