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Estuary Cormorants Abandon Nest, Eggs After 'Significant Disturbance;' Audubon Blames Feds' Hazing
Posted on Thursday, June 02, 2016 (PST)

As many as 16,000 nesting double crested cormorants abandoned their nests and eggs on East Sand Island in the lower Columbia River estuary and the U.S. Army Corps of Engineers does not know why they left.

The Portland Audubon Society says they know why: the Corps’ intense hazing and killing of the birds over the past two months has been the society’s constant worry since the plan to cull the cormorants was approved by the U.S. Fish and Wildlife Service last year.

“We hold the Corps, the Fish and Wildlife Service and the USDA (U.S. Department of Agriculture) completely responsible for what happened on East Sand Island,” said Audubon’s conservation director Bob Sallinger. “They put the island and the birds under intense and unprecedented pressure. Something went very, very wrong and the fact that this is different from previous years has to do with the intensity with which the Corps and its helpers have gone after these birds.”

This is the second year the Service has allowed the Corps to cull double-crested cormorants and oil eggs in nests in order to reduce cormorant predation on juvenile salmon, some of which are listed as threatened or endangered under the federal Endangered Species Act.

Nesting ended between May 13 and early May 16, according to the Corps, after a “significant disturbance” caused the birds to abandon their nests, leaving their eggs prey to gulls, eagles and crows.

As a result, the Corps immediately stopped all culling and egg-oiling activities on and near the island. Egg oiling ended May 11, prior to the disturbance, and the Corps suspended boat-based culling May 16 upon learning of the on-island colony situation, the Corps said in its weekly management report published May 26 at 

“We don't know the cause of the disturbance and wildlife biologists from several federal agencies are gathering information toward determining its cause,” the Corps said. “Investigation of the colony area did not find any mammalian tracks. Federal biologists observed as many as 16 bald eagles on the colony on May 17. We are monitoring the colony to see if birds return.”

Sallinger called the abandonment of nests by the cormorants a complete collapse of the colony and something Audubon had predicted.

“The federal agencies recklessly and relentlessly slaughtered these birds without scientific justification, and created conditions under which complete collapse of the largest double-crested cormorant colony in the world was a potential outcome,” Sallinger said. “The agencies are now trying to scapegoat eagles for the collapse of the cormorant colony just as they scapegoat cormorants for salmon declines.”

He added that no one should be surprised that the colony failed under these conditions. “Many groups, including Portland Audubon, raised exactly this concern when they submitted comments on the federal agencies’ cormorant killing plan.”

Some birds (about 4,000 as of May 20), however, have returned, but not to the nesting areas on East Sand Island, according to Amy Echols of the Corps. “Since then, some birds have been observed re-nesting, but we don’t have the latest count yet to know if these re-nesting birds are in addition to the 4,000 or from that group,” she added.

The Corps said the birds’ breeding season typically peaks mid-June through July, so there is time for the cormorants to return and lay eggs to produce young.

Whether the Corps will resume culling and egg-oiling again this year hinges on the number of cormorants that return to the colony and on their behavior, the Corps said. 

Sallinger objects to resuming the operation.

“The idea that they would go back in and start shooting again is unconscionable,” he said. “They need to take a step back and look at legal decisions that have been rendered and rethink the entire program if the birds do return. The idea that they would play Russian roulette a second time is unconscionable.”

The legal decision Sallinger referred to is on another coast. On May 25, U.S. District Judge John D. Bates of a federal district court in Washington D.C. threw out a cormorant culling program in 24 states east of the Mississippi river that has been run by Service.

The court found that the government failed to consider alternatives other than its preferred lethal control strategy and that the government failed to demonstrate that killing cormorants provided any appreciable benefit to the fish that the killing was meant to protect.

In South Carolina alone, about 26,000 cormorants were killed in two years.

The depredation order had been in effect since 1998, and had been renewed three times in 5-year increments.  The case was brought to the U.S. District Court by Public Employees for Environmental Responsibility. The court ruling can be found at

The Corps’ Matt Rabe said the situation is different between the two operations – the East Coast operation and the East Sand Island operation. “Our operation needs to look at this through our own lens and not the lens of another part of the country,” he said. 

The Corps requested a 2016 depredation permit for culling and oiling of eggs on East Sand Island from the Service in late January and received the go-ahead March 18.

Since then, Wildlife Services, the Corps’ contractor, has shot 2,394 cormorants from boats in the open water between East Sand Island and the Astoria/Megler Bridge, and has oiled 1,092 nests. 

The 2016 depredation permit allows the Corps to lethally take 3,114 double-crested cormorants, 93 Brandt’s cormorants and 9 Pelagic cormorants. The latter two species are allowed due to the recognition that some birds that are not double crested-cormorants will be misidentified and shot. Last year, the Corps culled over 1,700 birds and oiled more than 5,000 nests.

The permit also allows the Corps to destroy 5,247 double crested cormorant nests through egg addling by coating eggs with 100 percent corn oil, which suffocates the growing embryo inside the shell. Some 750 of those nests can be fully destroyed, according to the permit (

While predation rates vary from year to year, double-crested cormorants from East Sand Island on average have consumed 11 million juvenile salmon and steelhead annually over the past 15 years, according to the Corps. In recent years (2011-2013) consumption has averaged 18.5 million per year, researchers say.

Average annual double crested cormorant predation rates of juvenile steelhead originating upstream of Bonneville Dam have ranged from 2 to 17 percent over the past 15 years (depending on the run, or distinct population segment, and year).

Double crested cormorants are protected under the Migratory Bird Treaty Act and are native to the Columbia River estuary.

In April last year, after the Service issued its first depredation permit to the Corps, conservation and animal welfare groups, including the Audubon Society of Portland, filed a lawsuit in U.S. District Court of Oregon to stop the U.S. Army Corps of Engineers’ plan to kill and harass the cormorants in the Columbia River estuary. 

The plaintiffs said culling cormorants in the lower river is just a diversion from the real problems of fish recovery, the operation of the federal dams on the Columbia River.

That case is still in federal court under the jurisdiction of Judge Michael H. Simon, who also recently remanded NOAA Fisheries’ biological opinion for salmon and steelhead impacted by the federal Columbia/Snake River hydro system.

Audubon said the plan to reduce the entire population of cormorants west of the Rocky Mountains by 15 percent would have driven cormorant populations below levels defined as sustainable. It added that the potential loss of the entire East Sand Island colony places the cormorant populations in the west at “even greater risk and the killing that has already been done by the federal agencies in 2015 and 2016 will significantly reduce the resiliency that cormorant populations will have to recover from a catastrophic event such as what occurred on East Sand Island.”

For background, see: 

--CBB, May 13, 2016, “Corps More Than Two-Thirds Complete In Killing Over 3,000 Estuary Salmonid-Eating Cormorants,” 

--CBB, April 1, 2016, “For Second Year, Corps Issued Permit To Cull Cormorants In Lower Columbia; Allows Killing 3,216 Birds,”

--CBB, October 2, 2015, “Corps Increases Cormorant Culling In Recent Days; Killing Opportunities Ending Soon As Birds Disperse,” 

--CBB, August 14, 2015, “Audubon Releases Internal USFWS Report Questioning Whether Culling Cormorants Improves Fish Survival,” 

--CBB, May 29, 2015, “Culling Cormorants Begins: Goal Is To Reduce 15,000 Breeding Pairs To Under 6,000 by 2018,” 

--CBB, May 15, 2015, “Federal Judge Allows Corps’ Cormorant Culling Plan to Proceed In Columbia River Estuary,” 

--CBB, April 24, 2015, “Conservation, Animal Welfare Groups File Lawsuit To Stop Plan To Cull Estuary Cormorants,”

-- CBB, April 17, 2015, “USFWS Grants Corps One-Year Depredation Permit To Begin Culling Columbia Estuary Cormorants,”

-- CBB, March 27, 2015, “Audubon Announces Intent to Sue Corps Over Plan To Cull Cormorants From Columbia River Estuary,”

-- CBB, Feb. 6, 2015, “Final EIS Released On Reducing Estuary Cormorant Numbers; Proposes Both Shooting And Egg Oiling,”


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