Even Puerto Rico has breeding populations of about 20 kinds of exotic songbirds, far outnumbering the endemics. They readily adapted to their new environments, and most have prospered here for more than 100 years. Population trends from the Breeding Bird Survey, 1966-92. These birds were obtained in Florida, where they arrived in the early 1940's from South America by way of the West Indies. The cattle egret is highly migratory, and many of the American birds winter in Latin America.
Cattle egrets feed primarily in pastures with cattle.
Concerns that cattle diseases might be carried across international boundaries have so far lacked documentation, but populations are being monitored and movements of banded birds are being tracked. Waterfowl Many species of exotic waterfowl have found their way into the wild through intentional introductions and by escaping from captivity. Many European and some Asiatic ducks, and even a few exotic geese, escape from private collections, especially during storms. Because the number of these individuals is small, their populations have not been monitored. The mute swan of Eurasia is the notable exception.