The Cattle Egret was first recorded in Brazil on Marajó Island at the mouth of the River Amazon in 1964. It reached Brasilia in 1971, São Paulo in 1974 and Rio de Janeiro in 1976.

Having originated in Africa and southern Spain, it started its invasion of the Americas in the 1890s. A major factor in its rapid spread was the increase in cattle ranching for, as its name implies, the Cattle Egret is closely linked to cattle on which it depends to frighten and disturb the grasshoppers and other insects on which the Cattle Egret feeds.

Another reason for its rapid spread is that it begins to breed at the end of its first year and, in the tropics, it can have two broods each year.