Cattle Egret

The cattle egret is a stocky white heron with a short thick neck, sturdy bill and hunched posture. In the breeding season it develops orange-buff plumes on the back, breast and crown. It is native to tropical and subtropical Africa, western Asia and parts of southern Spain and Portugal. Unlike most herons, it favours drier, open habitats such as pastures, farmland and rice paddies, and it often follows cattle or other large mammals, catching the insects and small vertebrates they disturb. It nests in colonies on stick platforms in trees or shrubs, often with other wading birds. It has undergone one of the most rapid natural range expansions of any bird.

About the cattle egret

The cattle egret is a small, stocky white heron that feeds alongside cattle and other large grazing animals, snapping up insects they flush from the grass. It belongs to the heron family, Ardeidae, and is closer to the great herons of the genus Ardea than to most egrets. Native to Africa, southern Europe and Asia, it now lives worldwide.

Linnaeus first described the bird in 1758 as Ardea ibis, from specimens collected in Egypt. From 1855 it was placed in its own genus, Bubulcus (Latin for "herdsman"), as Bubulcus ibis, until a 2023 genetic study showed that the cattle egrets sit inside Ardea. The old species is also now usually split in two: the western cattle egret of Africa, Europe and the Americas, and the eastern cattle egret of southern and eastern Asia and Australasia. The IUCN still treats them as a single species. The "ibis" in the name was a mistake; it originally referred to the sacred ibis.

Compared with other herons, the cattle egret looks compact and hunched, with a relatively short, thick neck and a sturdy bill. It measures 46 to 56 cm (18 to 22 in) long, has a wingspan of 88 to 96 cm (34.5 to 38 in) and weighs 270 to 512 g (9.5 to 18 oz).

Outside the breeding season adults are mainly white, with a yellow bill and greyish-yellow legs. In breeding season, western cattle egrets grow orange-buff plumes on the crown, back and breast, and for a short time before pairing the bill, legs and eyes turn bright red. The sexes look alike, though males are slightly larger with slightly longer plumes. Juveniles lack the colored plumes. Rare melanistic birds with abnormally grey plumage have been recorded.

The eyes are placed to give binocular vision while feeding, and studies suggest the birds may be able to feed at dusk or night as well. Because they hunt on land, they have lost the ability of their wetland relatives to correct accurately for the way water bends light.

Behavior and diet

The cattle egret's lifestyle revolves around large animals. It walks with cattle, horses and wild grazers and catches the small creatures they disturb. Foraging beside cattle, an egret is 3.6 times more successful at catching prey than when feeding alone. It does nearly as well following farm machinery, though it has to move more.

Each bird weakly defends the space around its host animal against other cattle egrets, and dominant birds feed closest to the host. Where there is a choice, cattle egrets favor animals that walk at about 5 to 15 steps a minute. In Africa they follow plains zebras, waterbuck, blue wildebeest and Cape buffalo. They also pick ticks and flies off cattle, and a study in Australia found they reduced the number of flies bothering the herd.

Insects make up most of the diet, especially grasshoppers, crickets, flies and maggots, beetles and moths. Cattle egrets also take spiders, frogs, fish, crayfish, small snakes, lizards and earthworms. On islands with seabird colonies they eat the eggs and chicks of terns and other seabirds, and during migration they have been seen eating exhausted songbirds. In the Seychelles they chase sooty tern chicks until the chicks give up their food.

They are largely silent away from the colony, where they give a quiet, throaty "rick-rack." Some populations migrate and others wander after breeding. Young birds have been recorded dispersing up to 5,000 km (3,000 mi), and flocks have been seen over the middle of the Atlantic.

Cattle egrets nest in colonies, often near water, in woodland by lakes and rivers, in swamps or on small islands, sometimes alongside other herons, ibises and cormorants. The male displays in a tree with twig shaking and "sky-pointing," raising his bill straight up, and a new mate is chosen each season. Both parents build an untidy stick platform: the male brings sticks and the female arranges them, and stealing sticks from neighbors is common.

A clutch is one to five eggs, usually three or four, incubated by both parents for about 23 days. Chicks start climbing around the nest at two weeks, fledge at about 30 days and become independent at around 45 days. Starvation is the main cause of chick deaths, and in South Africa the third and fourth chicks of a brood always starve.

Range and habitat

Few birds have spread so far, so fast. The western cattle egret was once limited to southern Spain and Portugal, tropical and subtropical Africa and tropical Asia. It reached South America on its own in 1877, apparently by flying across the Atlantic, and was established there by the 1930s.

It arrived in North America in 1941, bred in Florida in 1953 and in Canada by 1962, and is now common as far west as California. It was introduced to Hawaii in 1959. In Europe it spread back through Spain and Portugal and into France and Italy, and it first bred in the United Kingdom in 2008. The eastern cattle egret colonized northern and eastern Australia from the 1940s and now breeds throughout Australia, apart from its drier parts, and New Zealand.

The driver of this expansion is livestock. A bird adapted to following wild grazers switched easily to domestic cattle and horses, and as farming spread, so did the egret. Unlike most herons, it lives mainly in fields and dry grassy places rather than wetlands, because it depends on land insects more than water prey.

Western vs eastern cattle egret

The two cattle egrets were long treated as one species and look very similar outside the breeding season.

Conservation status

The IUCN Red List treats the cattle egrets as a single species and lists it as Least Concern (BirdLife International, 2019). The range is enormous and the global population is estimated at 3.8 to 6.7 million birds. Its rapid spread has led to it being classed as an invasive species in places, though little if any impact has been recorded.

Adults have few predators. Crested caracaras have been seen forcing cattle egrets to the ground and killing them, and nests are raided by monkeys, crows, rats and eagles in different parts of the range.

The bird's relationship with people is mixed. Ranchers value it for eating ticks and flies, and that benefit is why it was released in Hawaii. But flocks feeding on grassy airport verges are a hazard to aircraft, and cattle egrets have been linked to the spread of livestock diseases such as heartwater.