CHINOOK — The goal at East Sand Island in the Lower Columbia River estuary near Chinook is to limit the number of double-crested cormorants nesting on the island to 5,600 breeding pairs to limit the birds’ impacts on juvenile salmon and steelhead, according to Jeffery Henon, spokesman for the U.S. Army Corps of Engineers.
However, he said, the Corps hasn’t observed any cormorant breeding pairs nesting at East Sand Island this year, which seems to be due to bald eagles harassing them.
Cormorants feed on juvenile salmon and steelhead, some of which are listed under the federal Endangered Species Act.
The U.S. Army Corps of Engineers began a 5-year management program to lethally remove or cull cormorants in order to limit nesting on the island in 2015, but suspended those actions last year and moved onto phase 2 of its management plan, which is to observe nesting and to limit the amount of nesting habitat available to the cormorants.
For two years, the Corps lethally culled, harassed and oiled cormorant eggs and nests to discourage nesting on the island, but since 2017 the birds had been late to nesting, which required the Corps to suspend culling operations April 27, 2017 and they have never resumed.
At that time, the Corps said that as many as 40 eagles were harassing the sea birds, keeping them from nesting on the island and driving them to other areas, such as local bridges, and Willapa Bay and Grays Harbor.
The second phase of its cormorant management program also includes hazing the birds and removing a limited number of eggs at the island as a way to keep the number of nesting pairs under control.
As another control measure, the Corps’ contractor, Wildlife Services, which was previously responsible for the lethal culling of cormorants, last year continued to fence off a nesting area on East Sand Island — a 1.3 acre plot — a limited plot on which they hope the cormorants will nest. Birds not in the confines of the fence last year were to be hazed. That work is now done.
“We completed the conversion of a portion of East Sand Island’s upland habitat into intertidal habitat in March 2019, so there won’t be any further changes to the designated Cormorant breeding area,” Henon said.
As the Corps works to limit space and numbers of birds on East Sand Island, the U.S. Fish and Wildlife Service is surveying cormorants at a local bridge where many have taken up residence to nest.
The USFWS counted birds at the Astoria-Megler Bridge, a more than four-mile long bridge that spans the Columbia River and connects Astoria and the Washington shore, on June 4, 13 and 24, finding a declining number of nesting pairs in each count:
June 4 had the highest observed number at 3,542. Counts decreased for the subsequent counts to 3,448 on June 13 and 2,884 on June 24. Motorist routinely see numerous cormorant carcasses on the bridge, where they are struck by motor vehicles, typically while flying low over the bridge deck.
“We nor FWS count cormorants at Youngs Bay Bridge,” Henon said.
The USFWS counts observable nests, which translates into a male and female breeding pair, Henon said. An egg that hatches into a fledgling has left its nest, which is why the number of observable nests decreases as the breeding season closes.