CHINOOK — Instead of shooting birds to control a large cormorant colony on East Sand Island, the U.S. Army Corps of Engineers will move into the second phase of its management plan and begin changing the landscape of the island itself.
The Army Corps’ efforts to check a growing double-crested cormorant colony and reduce predation on young threatened and endangered salmon included shooting adult birds and active hazing to push birds toward the western end of the island in Baker Bay just south of Chinook on the Oregon side of the state line. Phase two is more passive.
The Oregon Department of Environmental Quality is reviewing a proposal from the Army Corps to excavate portions of the island and make other changes to further restrict where the birds can build nests.
A large Caspian tern colony on the island has long been managed by limiting the amount of quality nesting habitat available.
“The whole point of our phase two activities is to lean toward a long-term solution that limits the need for human presence out there that could cause dispersal for the birds or disruption,” said Kris Lightner, an environmental specialist with the Army Corps.
This year, the Corps’ contractors tried to keep the seasonal double-crested cormorant nesting on one side of a privacy fence.
The agency also received a permit to destroy up to 500 double-crested cormorant eggs this year in an effort to further reduce the massive colony. In prior years — over objections and legal challenges by environmental and conservation groups — contractors shot adult birds.
As of mid-September, the Army Corps had only taken three eggs, all from nests built on the wrong side of the fence.
It is possible the agency may request another permit from the U.S. Fish and Wildlife Service to allow contractors to destroy eggs next year, too, but the Corps has not made a firm decision yet. The Corps typically requests a renewal of the depredation permit in January, said Miel Corbett, a spokesperson for Fish and Wildlife Service.
Double-crested cormorants abandoned the island and their nests in 2016 and 2017 — years when contractors were shooting adult birds. These events prompted the Audubon Society of Portland to demand that the Fish and Wildlife Service not issue a depredation permit to the Corps earlier this year until there could be a thorough investigation into why the birds left.
At the time, the Army Corps blamed bald eagles and potentially other predators for the disturbances. But, later, they also looked into the possibility that people working on or around the island as well as the culling caused the cormorants to leave the island.
“We don’t have any way to firmly say one specific action caused the abandonment,” Lightner said.
Observers on the island have not recorded any issues with the double-crested cormorant colony this year. Reports note the progression from the arrival of cormorants on the island to breeding and nesting behavior and the appearance of eggs then chicks.
By mid-August, a mix of small, younger double-crested cormorant chicks and larger, older chicks were seen on the island.
Another thing the Army Corps knows for certain is that contractors monitoring the colony are seeing even more cormorants nesting on the Astoria-Megler Bridge.
Cormorants often nest on the bridge, but observers counted a population boom there in 2016 and 2017. Where people were used to seeing an average of 75 to 100 nests each season, they found around 600 at one count in 2016.
“This colony has doubled or nearly doubled in size every year since (double-crested cormorants) began nesting here and it looks like that pattern will continue,” Lightner said.
It is possible the Oregon Department of Transportation will have to get a permit to remove nests and eggs in several years to complete scheduled maintenance on the bridge.