There was a population of Cattle Egrets on Easter Island from at least the 2000s to some time in the 2010s, but very little is known about it. According to Thibault & Cibois (2017), it is not even known whether the species was introduced to Easter Island, or colonised Easter Island by itself.
This blog post says what the fate of the population was:
This blog post says what the fate of the population was:
Cattle Egret (Bubulcus ibis) lived in groups, but their population was controlled after an accident at the airport. They say there is still one individual living in the nearby islets.