Alorton Heron Rookery, previously known as the William Nicholas heron colony, is an expansion of the Pontoon Beach Colony. This Category II Illinois Natural Areas Inventory site provides habitat for several rare species. It extends along the edge of the woods paralleling the Southern Railroad yard in Alorton, Illinois.
During the breeding season, wading birds use the area for nesting and feeding. This is one of the few sites in the state with a breeding population of Snowy Egrets and Little Blue Herons. Other birds to be found here include Yellow-crowned Night-Herons and Black-crowned Night-Herons.This site was chosen as an IBA because it met the criteria for Snowy Egrets and Little Blue Heron and wading birds.