Conserving the Nature of America

News Release

Final Environmental Assessment Released On Ohio Double-crested Cormorant Damage Management Control

March 31, 2006


Division of Public Affairs
External Affairs
Telephone: 703-358-2220

After considering comments submitted by individuals and groups during a public review process, federal and state agencies today released the final Environmental Assessment (EA), Decision document and Finding of No Significant Impact regarding double-crested cormorant management in Ohio.

Wildlife Services, a program of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, was the lead agency in developing the EA. The Interior Department’s U.S. Fish and Wildlife Service and its Ottawa National Wildlife Refuge, and the Ohio Department of Natural Resources’ Division of Wildlife were cooperating agencies.

The agencies have chosen an alternative that uses an Integrated Wildlife Damage Management approach to reduce damage associated with double-crested cormorants to natural resources, property and aquaculture, and cormorant-related risks to public health and safety in Ohio, where a need exists, a request is received, and the landowner grants permission.

Ohio is one of several states experiencing damage to natural resources by double-crested cormorants. The number of cormorants in Ohio has increased from no breeding pairs in 1991 to 5,164 pairs in 2005. The current double-crested cormorant population in North America is estimated at two million birds, nearly 70 percent of them in the interior population, which includes Ohio.

The cooperating agencies propose to reduce double-crested cormorant numbers in Ohio to a target population of 3,800 to 4,800 breeding birds over the next one to three years using a variety of techniques. When appropriate, physical exclusion, habitat modification or harassment would be used to reduce double-crested cormorant damage. In other situations, cormorants would be removed by shooting, egg oiling or destruction, nest destruction, or euthanasia following live capture.

Consideration will be given to practical and effective non-lethal methods. However, non-lethal methods may not always be applied as a first response to each damage problem. The most appropriate response in some situations could be a combination of non-lethal and lethal methods, or in some instances, using lethal methods alone may be the most appropriate strategy.

Initial efforts will focus on three Lake Erie islands—Turning Point, West Sister and Green—and two inland locations, Grand Lakes-St. Mary and the Portage Lakes, to lower or maintain current double-crested cormorant numbers in order to reduce cormorant damage to vegetation that provides habitat for other waterbirds.

The management objective for Turning Point is to maintain the current number of double-crested cormorants, about 400 breeding pairs. Although the cormorant density on Turning Point does not appear to be adversely affecting vegetation or other nesting species on the island, this could occur if the population increases much beyond current levels.

The cooperating agencies particularly want to protect habitat for colonial nesting waterbirds on West Sister by preventing further damage to vegetation caused by increased numbers of nesting and migrating double-crested cormorants.

Ohio’s only designated wilderness area, West Sister is a national wildlife refuge that currently hosts one of the largest remaining nesting colonies of herons and egrets in the U.S. portion of the Great Lakes, as well as one of two primary breeding colonies of black-crowned night herons in the state.

Currently, more than 3,800 pairs of cormorants nest on West Sister Island. Management goals under the EA call for reducing this number to no more than 2,000 breeding pairs, which is the population goal established for cormorants in the West Sister National Wildlife Refuge Comprehensive Conservation Plan finalized in 2000.

Green Island is used as a nesting site by great egrets and great blue herons, and is also home to the state and federally threatened Lake Erie watersnake, as well as several plant species listed by the state as threatened. The rate of double-crested cormorant population increase over the last two years – from no pairs in 2003 to 857 pairs in 2005 – has been alarming, especially given the relatively small size of the island, just over 17 acres. The management objective for Green under the EA is to remove all double-crested cormorants.

Ohio’s two small inland double-crested cormorant colonies are located approximately 195 miles apart and consist of a total of 86 cormorant pairs.

At Grand Lakes-St. Mary, the management objective is to reduce the cormorant population from 80 breeding pairs to 15. The state-owned land there is home to a great blue heron rookery and the site contains only a limited number of mature trees, fueling concerns that the growing double-crested cormorant colony could eliminate the vegetation needed by nesting herons.

Under the EA, the management goal at Portage Lakes is to maintain a minimum of six breeding pairs, the number of cormorants currently present at this site. In 2006, the Ohio Division of Wildlife will monitor activity in the Portage Lakes in response to public complaints regarding large flocks of migrating double-crested cormorants using this area.

At this time, the cooperating agencies do not plan to control double-crested cormorants in order to alleviate impacts to free swimming fish in open waters. No definitive evidence currently exists to indicate that cormorants are having a significant impact on free-swimming fish populations, but the agencies will continue to monitor the situation.

The environmental assessment considered four other alternatives, including a “No Action” alternative, which is required under the National Environmental Policy Act. The other alternatives considered included an approach that would restrict the federal agencies to non-lethal methods, an alternative that limited federal government involvement to providing technical assistance only, and an alternative under which federal agencies would not participate in any cormorant damage management activities.

Double-crested cormorants are large, fish-eating birds that nest in colonies and roost together in large numbers. A reduction in DDT and other eggshell-thinning pesticides, increased protection under the Migratory Bird Treaty Act, and abundant food resources on their breeding and wintering grounds have caused cormorant numbers and distribution to increase greatly in the last 30 years.

Impacts on vegetation and other colonial waterbirds that nest with cormorants, aquaculture and private property, and potential risks to recreational fisheries and human health and safety, led the cooperating agencies in Ohio to develop a damage management strategy for the species.

In 2003, the U.S. Fish and Wildlife Service issued regulations allowing more flexibility in the management of double-crested cormorants where they are causing damage to aquaculture stock and public resources such as vegetation, other birds and fisheries.

The regulations established a Public Resource Depredation Order allowing state wildlife agencies, tribes and USDA Wildlife Services in 24 states, including Ohio, to conduct cormorant damage management for the protection of public resources. Without this depredation order, agencies and individuals would not be able to use lethal methods to manage cormorant damage without a federal permit.

Agencies acting under the order must have landowner permission, may not adversely affect other migratory birds or threatened or endangered species, and must satisfy annual reporting and evaluation requirements. The U.S. Fish and Wildlife Service will ensure the long-term sustainability of regional cormorant populations and protection from damage control activities of other bird species nesting with cormorants through oversight of agency activities and population monitoring.

Copies of the final Environmental Assessment, Decision document and Finding of No Significant Impact on double-crested cormorant damage management in Ohio may be downloaded from the Fish and Wildlife Service’s Web site at
Hard copies may be obtained by contacting USDA-APHIS Wildlife Services, 6929 Americana Parkway, Reynoldsburg, OH, 43068, phone: (614) 861-6087.

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