Cattle Egret (Bubulcus ibis) has been very successful in colonising the earth. In fact it is found breeding in all six continents and as a rare vagrant in the seventh, Antarctica.
The bird was once confined to the Old World continents of Asia, Africa and Europe. However, during the last century or so it managed to cross the seas to Australasia.
Then sometime during the early part of the 20th century, a few Cattle Egrets found their way to South America. They did not fly across the Atlantic Ocean but blown westward across by a tropical storm. From Africa they landed in Guiana, at the North East coast of South America.
There, the Cattle Egrets settled and bred, spreading into North America by the 1940s. By the 1950s they were well into Florida. From there, they spread all over the warmer regions of the continent. They are now a common sight in North America.
The bird is a common winter visitor and passage migrant in Singapore. They generally move with cattle, catching insects that are disturbed by the latter. In the 1950s and 1960s when cows were literally roaming Singapore roads, Cattle Egrets were a common sight. Now that cows are banned from roaming freely all over the island, they are still a common sight.
Most of these are free-flying birds from the Jurong Bird Park, often seen in western Singapore but spreading rapidly throughout the country. They are breeding in large numbers within the park, establishing its status as a feral species.
Indeed, Cattle Egret is an example of a great avian success story.
Image by John Lynn.