Madison, Wisconsin: Wisconsin Department of Natural Resources
Summary
Natural nesting habitat for the double-crested cormorant (Phalacrocorax auritus), consisting of flooded dead timber, has become limited in the midwest portion of the United States. Population trends have followed this decline in habitat and today the species is classified as endangered in Wisconsin. Artificial nesting structures, consisting of a pole with platforms, proved to be a successful substitute for natural nest sites on the George W. Mead Wildlife Area in central Wisconsin and thus provided an excellent method for rehabilitating deteriorating natural rookeries. Platforms constructed with a lath surface, with additional perching space provided, were the most successful of the four platform designs tested, and received high use by cormorants and great blue herons. Cormorant production on artificial platforms was generally greater than that in natural nest sites.