Final Minnesota environmental assessment on cormorant management released; Leech Lake Band to initiate local control efforts (2005-05-02)

Federal, state and tribal agencies released a final Environmental Assessment on double-crested cormorant management in Minnesota, after considering comments submitted by more than 100 individuals and groups during a public review process.

The U.S. Department of Agriculture's Wildlife Services program was the lead agency on the Environmental Assessment; the U.S. Fish and Wildlife Service (USFWS), Minnesota Department of Natural Resources (DNR) and the Leech Lake Reservation Division of Resources Management (DRM) were cooperating agencies. The Environmental Assessment considered five alternatives for cormorant damage management in Minnesota.

Following the publication of the final Environmental Assessment, the Leech Lake DRM announced its decision to cull up to 80 percent of the cormorants from a colony nesting on the tribally owned and managed Little Pelican Island on Leech Lake. This specific control action was examined extensively in the draft Environmental Assessment, and likely will take one to three years to complete.

The final Environmental Assessment proposes to implement the Integrated Wildlife Damage Management alternative 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.

Under the proposed alternative, when appropriate, physical exclusion, habitat modification or harassment would be used to reduce double-crested cormorant damage. In other situations, cormorant numbers could be reduced by shooting, egg oiling or destruction, nest destruction, or euthanasia following live capture.

The other alternatives considered were a non-lethal control approach, an alternative that would continue current cormorant damage management activities, and two alternatives that limit federal government involvement in cormorant damage management in Minnesota.

Wildlife Services, USFWS and the Leech Lake DRM each signed a Finding of No Significant Impact on April 29, clearing the way for the cormorant control program on Leech Lake. Leech Lake DRM has contracted with Wildlife Services to do the culling work. While the DNR is funding a significant proportion of the culling operation this year, the Leech Lake Band plans to seek federal funding for future cormorant management activities, according to John Ringle, Fish and Wildlife Program Director for the Leech Lake DRM.

The number of cormorants that nest on Leech Lake increased from 73 pairs in 1998 to 2,524 pairs in 2004. There is mounting biological evidence that the increasing cormorant numbers have negatively effected walleye and yellow perch populations. DNR fisheries managers on Leech Lake have documented a marked decrease in yellow perch and several missing walleye year classes that coincide with the cormorant population increase.

Tribal biologists are also concerned that the cormorants may be displacing the common tern colony that also nests on Little Pelican Island. Common terns are a state- and tribal-listed threatened species and a species of special concern for the USFWS.

Sharpshooters in elevated blinds will cull adult birds using pre-charged air rifles to minimize disturbance from gunfire. These rifles have limited range, so legislation has been introduced in the Minnesota Legislature that would authorize the use of silencer-equipped .22 caliber rifles for this purpose. Without this legislation, it may not be possible to attain the desired management outcome as quickly as possible.

The goal is to reduce cormorant numbers on Leech Lake to 500 nesting pairs. Egg oiling, which prevents eggs from developing, may also be used on any nests above the 500 pair level.

"Boaters and anglers on Leech Lake should be advised that various law enforcement agencies have marked a quarter-mile buffer zone around Little Pelican Island and a portion of Big Pelican Island to ensure public safety," said Ringle. "This zone will be patrolled by DRM and DNR conservation officers, as well as the Cass County Sheriff 's Department, for the duration of the culling operation, which might last well into May."

In the interest of public safety, management activities will be suspended during the walleye fishing opener, May 14-15, according to Ringle.

In conjunction with the cormorant population reduction, the Leech Lake DRM, DNR, Wildlife Services and researchers from the University of Minnesota have initiated stepped-up research programs to better establish how cormorants might be impacting the lake's walleye and perch fisheries.

Researchers are cooperating on a diet study to get a better handle on the types and numbers of fish cormorants are consuming.

This research is being funded through a Tribal Wildlife Research Grant from the USFWS. DNR biologists are also conducting a mark-recapture study on marked walleye fry to establish the level of natural reproduction in the lake.

Results from these studies will be used to refine cormorant population goals for Leech Lake.

"Collecting detailed resource information on the Leech Lake fisheries and the factors that influence its health and sustainability is critical," according to Lee Pfannmuller, director of the Division of Ecological Services with the DNR. "This information, coupled with more accurate information on the role and impact of the cormorant population, will help guide the important resource management decisions that need to be made."

The double-crested cormorant is a native species that was historically common and widely distributed across Minnesota. The purpose of the culling operation is not to eliminate the colony of birds from Leech Lake, but to reduce their numbers to the point that they are not having a major impact on game fish populations or other colonial waterbirds.

Cormorants are protected by a 1972 amendment to the Migratory Bird Treaty Act, which gave USFWS primary responsibility for protecting cormorant populations in the United States. Federal regulations published in 2003 established a Public Resource Depredation Order, which allows federally recognized tribes, the USDA Wildlife Services program, and state agencies in 24 states (including Minnesota) to control cormorant populations when they have evidence of damage to public resources (fisheries, vegetation, and other bird species).

Copies of the Environmental Assessment are available upon request from the Minnesota Wildlife Services Office, 34912 US Highway 2, Grand Rapids, MN 55744, on the USFWS Regional Office Web site at www.fws.gov/midwest/NEPA, or from the U.S. Fish and Wildlife Service, Division of Migratory Birds, 1 Federal Drive, Fort Snelling, MN 55111.

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