Bald eagles harass cormorants, so Corps stops culling program

Bald eagles continue to harass double-crested cormorants at East Sand Island in the lower Columbia River estuary, essentially bringing all nesting activity on the island to a halt.

Throughout June, bald eagles have driven the cormorants from the island and onto bridges in the area to nest. U.S. Army Corps of Engineers observers have also seen several thousand cormorants nesting in Willapa Bay as well as up the coast in Grays Harbor.

Culling of the cormorants was suspended April 27 due to “lack of colony formation on the island. Photos show daily attempts by double-crested cormorants to initiate nesting are continually interrupted by widespread disturbances by bald eagles,” according to a Corps timeline, and has not resumed.

The program to cull and oil nests, as well has other hazing activities to otherwise discourage the presence of cormorants in the lower Columbia River estuary is designed to protect migrating threatened and endangered salmon and steelhead smolts by reducing the cormorant population that feed upon them. It is an action called for by reasonable and prudent alternative 46 of the 2014 biological opinion for Columbia River salmon and steelhead.

By June 20, the Corps says in its management update, “Aerial surveys conducted over the Columbia River are unable to find vast numbers of cormorants in the estuary, though about 1,000 to 1,500 are observed at the south shoreline.”

On that same date, nest surveys at the Astoria-Megler Bridge that crosses the Columbia River upstream of East Sand Island found 686 double-crested cormorant and 76 pelagic cormorant nests, with some Brandt’s cormorants “loafing” on the lower part of the bridge.

By June 26, 7,000 to 9,000 of the sea birds were seen clustered tightly along the shoreline of East Sand Island, the update says in its last entry for the month. While there were 12 bald eagles present, there were no dispersal events.

The ebb and flow of cormorants on the island was typical for June.

Some 8,500 of the birds were observed on the island June 5, but harassment by 25 to 30 eagles had dispersed nearly all the cormorants by the next day.

The birds continue to move to local bridges. The Lewis and Clark Bridge that spans Youngs Bay in Astoria had 146 active nests on June 6, and as many as 10,000 cormorants overnighted on the Astoria-Megler Bridge June 10.

Some 3,000 to 4,000 cormorants returned June 13, but as many as 17 eagles dispersed them on and off over the day. When the Corps visited the island that day, they saw two cormorant carcasses, along with eggshell fragments over the entire island, “confirming that cormorants attempted nesting earlier in the season.”

The number of nests observed June 17 on the Astoria-Megler Bridge dropped slightly to 645 double-crested and 77 pelagic nests. Chicks were present that were estimated to be seven to 10 days old. About 10,000 cormorants roosted on the bridge overnight.

On June 15, Bob Sallinger, conservation director for the Portland Audubon Society, sent a letter to the U.S. Fish and Wildlife Service, which has issued three depredation permits to the Corps, urging the Service to withdraw the permit and terminate the project.

“It is time to permanently terminate this project,” the letter says. “We urge the US Fish and Wildlife Service to permanently withdraw the depredation permits that it issued earlier this year and allow the rewrite of the Columbia River Salmon BiOp, ordered by the Federal Court in Oregon, to be completed before considering next steps regarding cormorants on East Sand Island.”

The Service’s response to Sallinger says it is aware of what is happening with the cormorants in the estuary and is working with the Corps to monitor and manage the situation.

“This is consistent with the two phone conversations we had with them this season,” Sallinger said. “In the first (early in the season) they told us that they were adding no measures at all to address last year’s collapse when they issued this year’s permits. In the second, more recently, they said that they were leaving it up to the Corps as to how to address this year’s decline and that the adaptive management framework in the EIS was sufficient.”

Some 16,000 cormorants also left their nests in 2016. Sallinger called that incident a complete collapse of the largest double-breasted cormorant colony on the West Coast and blamed the hazing and culling for the collapse. He likened the event with what is happening today at East Sand Island.

This is the third year in a row the Corps has been shooting cormorants in areas of the lower estuary (generally west of the Astoria-Megler Bridge to East Sand Island) and dousing eggs and destroying nests on the island.

The plan calls for reducing the double-crested cormorant population in the estuary from about 13,000 nesting pairs to 5,300-5,900, all by late 2018.

This year’s goal is to shoot 2,409 birds and addle eggs in 4,058 nests (750 nests are allowed to be destroyed). The Corps has through January 31, 2018 to complete this year’s actions.

In addition to double-crested cormorants, in 2017 the agency is allowed to take 72 Brandt’s cormorants and seven Pelagic cormorants for depredation control purposes due to misidentification of the birds in 2017.

The largest colony of nesting Caspian terns feeding on juvenile salmon and steelhead in the lower Columbia River estuary has also been a problem, and the Corps is proposing a relocation area in the Lower Klamath National Wildlife Refuge along the California/Oregon border.

The primary purpose of the proposed action is to develop alternative nesting habitat locations for Caspian terns, in conjunction with social facilitation measures, with the intention of reducing the number of terns nesting at East Sand Island in the Columbia River Estuary, thereby reducing their predation on juvenile salmonids through the estuary.

The Corps is seeking public comment on a draft supplemental environmental assessment (SEA) for the Caspian Tern Nesting Island Construction Project, which includes a draft Amended Finding of No Significant Impact and a Clean Water Act Section 404 Alternatives Analysis.

The draft SEA evaluates the environmental effects of demolishing a floating island on Sheepy Lake within the Lower Klamath National Wildlife Refuge and constructing a permanent rock island in its place, according to a Corps news release (http://www.nwp.usace.army.mil/Media/News-Releases/Article/1232523/corps-seeks-public-comment-on-changes-to-caspian-tern-nesting-proposed-actions/.

Questions or comments regarding the draft document should be directed to Mr. Paul Schmidt by phone at 503-808-4772, via email at sheepy-lake@usace.army.mil, or by mail to:

District Engineer

U.S. Army Corps of Engineer District, Portland

Attn: CENWP-PM-E/Paul Schmidt

P.O. Box 2946, Portland, Oregon 97208-2946.

The Corps will consider all comments received or postmarked by July 27, 2017, and make a determination regarding the significance of impacts resulting from the proposed action. Reference public notice number CENWP-PM-E-17-02 in the response.