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State begins to move birds off Astoria Bridge

Biologists with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service prepare to begin hazing double-crested cormorants off the Astoria Bridge in early March. Photo by Katie Frankowicz/KMUN

Flaggers stop traffic in both directions and the Astoria Bridge falls silent. Until the fireworks begin.

The pyrotechnics go off in lone bursts with long gaps in between, each one leaving a thin trail of smoke that hovers over the Columbia River. Angela Beers-Seydel, a spokeswoman for the Oregon Department of Transportation, leans against the guardrail and looks down. Just north of the bridge’s tall main span, black, angular shapes whirl out from under the bridge and circle over the river.

“I would say the birds noticed,” she said.

The flashes and bangs are an attempt to frighten double-crested cormorants off sections of the bridge ahead of maintenance and construction work this year.

After a test run, state and federal crews feel confident the birds will respond as desired. Hazing will continue throughout the nesting season, from spring through early fall, and for the next two years.

Double-crested cormorants, with their dark feathers and long, distinctive crooked necks, have nested in increasing numbers on the bridge.

Several years ago, they abandoned one of the largest cormorant colonies in the world at East Sand Island, an island near the mouth of the river near the Washington state village of Chinook.

Arguing that the birds ate too many threatened and endangered juvenile salmon, the U.S. Army Corps of Engineers shot thousands at East Sand Island, destroyed nests and eggs and reshaped the island’s habitat in an effort to reduce the massive colony’s numbers by about half.

The lethal management plan began in 2015 and ended in 2018. The cormorants abandoned the island several times in those years and, as far as observers can tell, they have not successfully nested on the island since.

Advocates and conservation groups critical of the Army Corps’ actions have called it a complete collapse of a colony that once represented around 40% of the entire double-crested cormorant population west of the Rocky Mountains.

‘An emerging issue’

Thousands of the cormorants have since moved to the Astoria Bridge.

Now the fish-eating birds have become a problem for the Department of Transportation. The cormorants’ guano is corroding a protective paint job on the bridge and their sheer numbers make regular maintenance and inspection work difficult.

“This is an emerging issue across Oregon bridges,” she said. “We don’t really have it quantified yet, but as we’re doing work on the bridges, as we are inspecting the bridges … we’re finding more and more birds.”

The state is preparing to launch hazing efforts at the Yaquina Bay Bridge in Newport this year as well.

Still, the Astoria Bridge remains a special case.

In 2020, more than 5,000 breeding pairs were counted on the supports and platforms that form the bridge’s understructure. Last year, that number dipped to 4,151. But both counts are estimates and represent only what can be seen and counted in boat and aerial surveys at any given time.

The state has budgeted $225,000 to contract with crews from the Animal and Plant Health Inspection Service, part of the U.S. Department of Agriculture, for three years to haze the birds off the bridge. The state budgeted $35,000 for hazing at Yaquina Bay, where a much smaller colony of mostly pelagic cormorants has set up shop.

“Maintaining a bridge is a cost that we have to have,” Beers-Seydel said. “That’s why we’re looking at different measures on working with the birds and getting them to nest someplace else so we can have it that we do what we need to do and they do what they do.”

‘Wards of the state’

To some researchers, the state’s hazing represents an opportunity to reestablish a cormorant colony at East Sand Island. Studies have suggested that, despite the Army Corps’ arguments when the agency was developing a management plan for the birds, the cormorants actually eat fewer salmon and more of other types of fish when they are at the mouth of the river rather than on the bridge.

Dan Roby, a professor emeritus from Oregon State University, spent years on East Sand Island working with the formerly huge Caspian tern colony there and, later, the growing double-crested cormorant colony.

Ahead of the Army Corps’ management plan, he and his research team urged the agency to pursue nonlethal methods, worried about the potential of colony collapse and the dispersal of birds to less desirable locations in the Columbia River estuary. They felt their research and recommendations were ignored.

Recently, Roby and researchers with Bird Research Northwest approached the state with a recommendation to attract cormorants off the bridge and back to East Sand Island. They believe it is possible to maintain a smaller colony at the island, solving, as they see it, many people’s problems with the birds.

The Army Corps, which manages East Sand Island, has not shown any interest in luring birds back to the island. In a statement, the agency said it considers the objectives of its management plan successfully met.

The state, however, is looking into management possibilities. The state had previously reached out to the Army Corps about partnering to get the birds off the bridge without any luck.

Over the years, the Army Corps has not linked the movement of double-crested cormorants farther upriver to management actions on East Sand Island. Instead, the agency points to predation by eagles and gulls as a reason for the cormorants’ departure and continued lack of successful nesting.

Roby predicts that without more active management to restore the abandoned colony on East Sand Island, what remains of the cormorants’ diminished interest in nesting there could disappear.

The terns are also in trouble. Attacked by eagles and other predators and restricted to an acre of nesting habitat under a management plan by the Army Corps, it appears the East Sand Island terns have not had a single chick survive to the fledgling stage for the last two years.

Roby doesn’t see a future for the birds without people taking on the management work to reduce disturbances and enhance nesting habitat.

“It’s not going to happen on its own,” he said. “We’ve changed the environment so much that these birds, in a sense, have become wards of the state — that they need our help if they’re going to be in the environment with us.”