Conservation 

Double Crested Cormorant

The Great Lakes population of double-crested cormorants was devastated during the 1960s, primarily by the effects of chemical contamination especially DDT, which ingested from the fish they ate. These chemicals caused reproductive failure, and chicks that hatched sometimes had crossed bills, club feet, and eye and skeletal deformities. In addition to contamination nest destruction contributed to the decline. In the 1800s and early 1900s, cormorants were frequently shot, and their numbers declined with westward settlement. In Wisconsin, the species was placed on the list of threatened and endangered wildlife. Nesting platforms were erected to aid their recovery. In 1972, double-crested cormorants were added to the list of species protected by the 1918 Migratory Bird Treaty Act. The use of chemical was banned. Since the 1970s, cormorant populations have grown steadily, even explosively. Today, the Great Lakes population of double-crested cormorants is at historic highs. Pollution control has lowered concentrations of toxic contaminants in their food supply, food is ample throughout their winter and summer ranges, and they are protected by federal and state laws. Nesting populations can be found on all the Great Lakes in both United States and Canadian waters, on inland lakes like Lake Champlain and Oneida Lake, and on the Niagara River. In the Great Lakes, some cormorant colonies have doubled in five years. The U.S. Fish and Wildlife Service will cooperate with state and federal fish and wildlife management agencies to develop a regional management plan for double-crested cormorants. While the plan is being developed, the Service is preparing a comprehensive assessment of the population status of cormorants, and a review of the impacts of double-crested cormorants on commercial and sport fish populations in both natural and artificial settings.

Sources

Wikipedia

www.allaboutbirds.org/guide/double-crested_cormorant/id

http://www.fws.gov/