Four natural resources agencies are seeking public comments on a draft environmental assessment (EA) that lays out a plan to manage double-crested cormorants in Minnesota.
In a partnership among state, federal and tribal resource agencies, the Interior Department’s U.S. Fish and Wildlife Service, the U.S. Department of Agriculture Animal and Plant Health Inspection Service’s Wildlife Services, the Minnesota Department of Natural Resources, and the Leech Lake Band of Ojibwe’s Division of Resources Management have drafted a plan to reduce damage from double-crested cormorants in Minnesota. Wildlife Services is the lead agency for the EA; the Fish and Wildlife Service, the Minnesota Department of Natural Resources and the Leech Lake Band of Ojibwe’s Division of Resources Management are cooperating agencies.
The draft EA proposes to implement an Integrated Wildlife Damage Management approach to reduce damage associated with double-crested cormorants to property, aquaculture and natural resources, and cormorant-related risks to public health and safety in Minnesota where a need exists, a request is received, and landowners grant permission.
The EA considers five alternatives, including the proposed integrated management approach and a “No Action” alternative, which is required under the National Environmental Policy Act. The other alternatives being considered include a non-lethal control approach and one alternative that limits federal government involvement to providing technical assistance only.
Under the proposed alternative, when appropriate, physical exclusion, habitat modification or harassment would be used to reduce double-crested cormorant damage. In other situations, cormorants might be removed by shooting, egg oiling or destruction, nest destruction, or euthanasia following live capture.
In determining the damage management strategy under the proposed alternative in the draft EA, preference would 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 could be a combination of non-lethal and lethal methods, or there could be instances where the application of lethal methods alone would be the most appropriate strategy.
The expanding number of double-crested cormorants in Minnesota reached the point of concern in the past few years, when the colony on Leech Lake expanded from 73 nesting pairs in 1998 to 2,524 nesting pairs in 2004. Biologists from the Leech Lake Band of Ojibwe and the Minnesota Department of Natural Resources believe that cormorants may be negatively affecting the lake’s colony of common terns, a threatened species in Minnesota, as well as the lake’s walleye and yellow perch populations.
Because the cormorant colony on Leech Lake is located on a tribally owned island, the Leech Lake Band has taken the lead in using methods to reduce the number of cormorants that nest on the island. Under this plan, additional methods will be available to reduce cormorant numbers in addition to the nesting material reductions that have already been completed. Under the proposed alternative in the draft EA, and under several other alternatives being considered, a special effort would be made at Leech Lake to reduce the double-crested cormorant population by 80 percent.
The draft EA covers damage management measures statewide, as cormorants may cause losses at aquaculture facilities, damage private property or public resources throughout the state, and pose risks to human health and safety. A 2004 Minnesota Department of Natural Resources study of colonial waterbirds estimates a statewide population of about 16,000 nesting pairs of double-crested cormorants. The current population in North America is estimated at two million birds, nearly 70 percent of which are in the interior population, which includes Minnesota.
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 fisheries, vegetation and other birds.
The regulations established a Public Resource Depredation Order allowing state wildlife agencies, tribes and Wildlife Services in 24 states, including Minnesota, 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 bird species, threatened or endangered species, and must satisfy annual reporting and evaluation requirements. The Service will ensure the long-term sustainability of cormorant populations through oversight of agency activities and regular population monitoring.
Double-crested cormorants are large, fish-eating birds that nest in colonies and roost together in large numbers. A reduction in eggshell-thinning pesticides (primarily DDT), increased protection under the Migratory Bird Treaty Act, and abundant food resources on their wintering grounds has caused cormorant numbers and distribution to increase greatly in the last 30 years.
Conflicts with human and natural resources, including real or perceived impacts on commercial aquaculture, private property, recreational fisheries, vegetation and other colonial waterbirds that nest with cormorants, and risks to human health and safety, led to a decision by the cooperating agencies in Minnesota to develop a management strategy for the species.
Copies of the draft EA on double-crested cormorant management may be downloaded from the Fish and Wildlife Service’s Web site at
