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Cormorant Management in the Columbia River Estuary

The Corps' Portland District submitted a Migratory Bird Treaty Act permit renewal request to the U.S. Fish and Wildlife Service in late January 2016 to resume management culling actions in the Columbia River Estuary to reduce predation by double-crested cormorants on salmon and steelhead listed under the Endangered Species Act. The actions will continue implementation of the selected alternative in the Corps' final Environmental Impact Statement and Cormorant Management Plan.

The U.S. Fish and Wildlife Service issued the depredation permit renewal on March 18, 2016 and management actions began April 6, 2016.

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Below are weekly summaries for management action on/near East Sand Island. Updates are posted by noon Thursdays.

Reporting Period

April 6-13, 2016

Individual adult Double-crested cormorants culled for the reporting period:  271

Total to date: 271

Individual adult Brandt's cormorants taken for the reporting period: 0

Total to date: 0

Nests oiled for the reporting period: 0

Total to date: 0

April 14-20, 2016

Individual adult Double-crested cormorants culled for the reporting period: 440

Total to date: 711

Individual adult Brandt's cormorants taken for the reporting period: 0

Total to date: 0

Nests oiled for the reporting period: 0

Total to date: 0





April 21-27

Individual adult Double-crested cormorants culled for the reporting period: 

Total to date:

Individual adult Brandt's cormorants taken for the reporting period: 0

Total to date: 0

Nests oiled for the reporting period: 0

Total to date: 0

In 2014, the U.S. Army Corps of Engineers released a draft Environmental Impact Statement and management plan to reduce predation of juvenile salmon and steelhead by double-crested cormorants in the Columbia River Estuary. In developing the plan, the Corps has worked closely with the following cooperating agencies: the U.S. Fish and Wildlife Service, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service - Wildlife Services, the Oregon Department of Fish and Wildlife and the Washington Department of Fish and Wildlife.

East Sand Island's double-crested cormorant colony has grown from approximately 100 pairs in 1989 to 14,916 nesting pairs in 2013, which accounts for more than 40 percent of the western population. This breeding colony is the largest in North America.

The Corps has been conducting research studying the impact of avian predation on juvenile salmonids in the Columbia River Estuary since 1997. The research on East Sand Island contributes to understanding of the impacts cormorants have on juvenile salmonids migrating out to the ocean. Click here to see two graphics demonstrating the impact of the cormorant colony on East Sand Island to salmonids. The first graph shows annual consumption of juvenile salmonids by the colony. The second graph shows the seasonal proportion of salmon the double-crested cormorants consume during their nesting season.

In 2008, the Corps began small-scale management feasibility studies on the double-crested cormorant colony, restricting the birds from nesting in specific locations on East Sand Island. Study methods included hazing with lights, reducing nesting habitat and using human presence to flush double-crested cormorants off potential nesting sites.

In 2011, the studies focused on reducing the amount of available nesting habitat for double-crested cormorants on the western portion of the island and tracking the dispersal of radio- and satellite-tagged individual double-crested cormorants. Habitat reduction was primarily accomplished by installing barrier fences and using human hazers to flush birds from the non-designated nesting area.

In 2013, double-crested cormorants were restricted to 4.4 acres. Eighty-three adult double-crested cormorants were marked with satellite transmitters and several hundred adults were banded with leg bands to provide information about where double-crested cormorants would move during the dissuasion efforts. Although reduced by 70 percent, available habitat was not completely limited and 14,900 breeding pairs ultimately nested on the island. Near-term dispersal locations of radio and satellite tagged double-crested cormorants during the 2011–2013 breeding seasons were generally to four main areas identified in geographic proximity to East Sand Island:

  1. Columbia River Estuary (defined as the tidally influenced 172 river miles from the mouth of the Columbia River to Bonneville Dam, including the Willamette River down to Willamette Falls Locks)
  2. Outer Washington coast (Willapa Bay and Grays Harbor)
  3. Puget Sound
  4. Northern Salish Sea (San Juan Islands, Strait of Georgia, Vancouver, BC) (BRNW 2014).

Of these areas, the Columbia River Estuary has had the highest levels of use by double-crested cormorants during the dissuasion research in 2012 and 2013. There were no confirmed detections of radio- or satellite-tagged double-crested cormorants at inland sites east of The Dalles Dam, or at coastal sites south of Cannon Beach, Oregon.

In 2015, the Corps prepared a final Environmental Impact Statement and has made the document available for public review. Brig. Gen. John Kem, the U.S. Army Corps of Engineers Northwestern Division commander, signed a record of decision for the Double-Crested Cormorant Management Plan Final Environmental Impact Statement March 19, 2015. The ROD documents Kem’s decision and rationale for adopting the management plan to reduce predation on juvenile salmon and steelhead listed under the Endangered Species Act by a growing population of double-crested cormorants in the Columbia River estuary.

The Corps selected alternative C-1 in the final EIS, to carry out actions in the management plan. In phase one, actions would include culling individuals and oiling eggs to achieve a colony size of about 5,600 breeding pairs by 2018. In phase two, the western portion of East Sand Island would be inundated to preclude nesting, and the Corps would continue monitoring and hazing efforts. If needed, limited egg take would continue as well.

Alternative C-1 uses adaptive management methods to determine the following year’s actions. We will work with the U.S. Fish and Wildlife Service’s migratory bird team when developing each year’s actions. The team will analyze the long-term sustainability of the double-crested cormorant colony at East Sand Island and the western population. The number of individuals culled and eggs oiled in each year will be based on the team’s analysis.

To carry out the actions in the plan, The Corps of Engineers applied for and was granted a depredation permit from the U.S. Fish and Wildlife Service. The permit allows the Corps to cull a specific number of individual adults and oil a specific number of eggs to meet the plan’s goals. The Corps must apply for a depredation permit each year. 

Site preparation for management actions was completed on East Sand Island by mid-April. This included placing fencing to minimize disruption of other bird species also found on the island and help minimize disbursing the birds to other island and off-island nesting locations. The fencing also facilitates counting and tracking of the bird population.


The Corps released its final Environmental Impact Statement on Feb. 6, 2015. 

Brig. Gen. John Kem, the U.S. Army Corps of Engineers Northwestern Division commander, signed a record of decision for the Double-Crested Cormorant Management Plan Final Environmental Impact Statement March 19, 2015.

The Corps requested and received a depredation permit from the U.S. Fish and Wildlife Service on April 13, 2015. The permit allows the Corps to cull a specific number of individual adults and oil a specific number of eggs to meet the goals of the plan. The Corps must apply for a depredation permit each year. 


In 2008, NOAA Fisheries issued a Biological Opinion on the operations of the hydropower dams that make up the Federal Columbia River Power System. NOAA Fisheries concluded that operating the FCRPS in accordance with the BiOp would not jeopardize the continued existence of ESA-listed species; nor would it adversely modify or destroy the species’ critical habitat if the action agencies implemented the BiOp’s recommended reasonable and prudent alternative. The RPA includes improving fish passage at dams, managing flow, controlling predators that prey on young salmon, improving tributary and estuary habitat and reforming hatchery practices. Two RPA actions from the 2008 FCRPS BiOp specifically address management of double-crested cormorants in the Columbia River Estuary.

  • RPA action 46 requires the development of a management plan for double-crested cormorants in the Columbia River Estuary and implementation of warranted actions in the estuary.
  • RPA action 67 requires the double-crested cormorant population in the Columbia River Estuary and its impact on out-migrating juvenile salmonids to be monitored and implementation of a management plan to decrease predation rates, if warranted.

In 2014, NOAA Fisheries released the Supplemental FCRPS BiOp with a revised RPA action for reducing double-crested cormorant predation. RPA action 46 was revised to read: “The FCRPS Action Agencies will develop a cormorant management plan (including necessary monitoring and research) and implement warranted actions to reduce cormorant predation in the estuary to Base Period levels (no more than 5,380 to 5,939 nesting pairs on East Sand Island).”

The EIS alternatives address the management objectives recently identified in revised RPA action 46. This equates to reducing the current double-crested colony size by about 60 percent.

The range of alternatives under consideration to reduce double-crested cormorant predation of juvenile salmonids include implementing non-lethal and lethal actions to reduce the colony size on East Sand Island and limit their dispersal within the Columbia River estuary. Non-lethal methods include various hazing techniques to prevent colony establishment, modifying available habitat to limit colony size and conducting hazing activities off East Sand Island. Lethal methods include shooting individual double-crested cormorants and the take of eggs.

The Corps is the lead agency on the Environmental Impact Statement under the National Environmental Policy Act. The following agencies are cooperating: U.S. Fish and Wildlife Service; U.S. Department of Agricultures' Animal and Plant Health Inspection Service-Wildlife Services; the Oregon Department of Fish and Wildlife; and the Washington Department of Fish and Wildlife.

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Phone: 503-808-4510

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East Sand Island images

Studies and plans

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The Pacific Flyway Council is an administration composed of directors or appointees from the public wildlife agencies in each state and province of the western United States, Canada, and Mexico. In the U.S., the Pacific Flyway includes Alaska, Arizona, California, Idaho, Nevada, Oregon, Utah, Washington, and those portions of Colorado, Montana, New Mexico, and Wyoming west of the Continental Divide.

In July 2012, the Council finalized A Framework for the Management of Double-crested Cormorant Predation on Fish Resources in the Pacific Flyway. This plan provides a framework to follow when addressing fish depredation issues involving double-crested cormorants, and includes information concerning biology, status, resources conflicts, management options, regulatory requirements and recommended management strategies. The Corps is evaluating this plan for consistency with the alternatives. http://pacificflyway.gov/Documents/Dcc_plan.pdf

In 2013, the Pacific Flyway Council published a Monitoring Strategy for the Western Population of Double-Crested Cormorants. The Corps plans to follow the guidelines identified in this monitoring strategy during any proposed management of the East Sand Island colony the EIS. http://pacificflyway.gov/Documents/Dcc_strategy.pdf