Cattle Egret - Ardea ibis
Since Cattle Egrets were first recorded in Australia in 1948, their range has expanded to include eastern and northern Australia, and also along major inland river systems. Their breeding colonies are often shared with other species of waterbirds, especially herons, ibis and other egrets. Cattle Egrets are usually seen stalking about in pasture, accompanying cattle to snap up insects as they are disturbed by the beasts. They also follow other grazing animals, including sheep, horses, goats, alpacas, and in zoos, elephants!
(Text Source: BirdLife Australia)