Those with an ornithological bent who travel the world checking species off their life lists might tend to dismiss cattle egrets. After all, flocks of these small, white herons foraging in pastures and along roads are a common site—on six continents! That was not always the case.
Cattle egrets are native to Africa. Since the late 1800s they have expanded their range across the world. Cattle egrets first flew to South America in 1877. They reached the United States in 1941, and started nesting by 1953. Now, they are one of the most abundant North American herons and are found all the way to Alaska and Newfoundland breed in nearly every state. An equally dramatic expansion has occurred in Asia and Europe and Australia.
How were cattle egrets able to colonize five other continents so quickly? They are perfect world travelers. They are very adaptable to new environments, on land or water. They are gregarious, opportunistic feeders that disperse great distances in random directions. In short, these birds don’t care where they go, as long as they go there together and there is a meal waiting at the end.
In marshes, swamps, ponds, or other aquatic environments, cattle egrets will nosh on frogs and fish like other herons. But they are really more at home foraging in grass than in water. In their African homeland, cattle egrets feed in groups and eat insects that are stirred up by wild animals. They are often seen riding on the backs of large, hoofed mammals. As they feed on insects, they do a peculiar head-quiver before they strike. Perhaps it helps them gauge the prey’s distance. As more domestic cattle were bred and raised in Africa, the egrets adapted to agriculture and followed cattle, horses, and tractors to catch the grasshoppers, crickets, spiders, and flies that were kicked up.
Cattle egrets live in colonies and are very sociable, both in and out of the breeding season. They nest with other heron and egret species and need to be closely packed together to stimulate pairing. To attract a mate, egrets start to display the buff plumes on their head, breast, and back. The male bird collects twigs, branches, and reeds for a nest and his chosen female builds it. She lays three to six eggs and both parents incubate the eggs and care for the chicks.
By six weeks, the young are strong flyers. Once they fledge, they wander long distances in all directions. Who knows where they might end up? Maybe the destination is a field, pasture, pen, swamp, dump, or airstrip. Roadsides, parks, sports fields, and lawns work, too. Lots of bugs get kicked up by lawnmowers, tractors, horses, and cattle.
Cattle egrets may compete with native species for nest sites in some areas, but in general, their impact on native species is considered minimal. In many areas they are considered beneficial because they help control flies and other insect pests.