A bipartisan group of lawmakers on Monday urged the Trump administration to scrap plans to kill more than 450,000 invasive barred owls in West Coast forests as part of efforts to stop the birds from crowding out a smaller type of owl that’s facing potential extinction.

The 19 lawmakers — led by Republican Rep. Troy Nehls, a Texas conservative, and Democrat Rep. Sydney Kamlager-Dove, a California liberal — claimed the killings would be “grossly expensive” and cost $3,000 per bird.

They questioned if the shootings would help native populations of northern spotted owls, which have long been controversial because of logging restrictions in the birds’ forest habitat beginning in the 1990s, and the closely related California spotted owl.

Barred owls are native to eastern North America and started appearing in the Pacific Northwest in the 1970s. They’ve quickly displaced many spotted owls, which are smaller birds that need larger territories to breed.

An estimated 100,000 barred owls now live within a range that contains only about 7,100 spotted owls, according to federal officials.

Under a U.S. Fish and Wildlife Service plan approved last year, trained shooters would target barred owls over 30 years across a maximum of about 23,000 square miles (60,000 square kilometers) in California, Oregon and Washington.

The plan did not include a cost estimate. But the lawmakers said in a letter to Interior Secretary Doug Burgum that it could top $1.3 billion based on extrapolating costs from a grant awarded to the the Hoopa Valley Native American Tribe in California to kill up to 1,500 barred owls.

“This is an inappropriate and inefficient use of U.S. taxpayer dollars,” the lawmakers wrote. “This latest plan is an example of our federal government attempting to supersede nature and control environmental outcomes at great cost.”

A U.S. Fish and Wildlife Service spokesperson did not immediately respond to questions about the cost estimate and the owl removal program. The agency’s plan called for more than 2,400 barred owls to be removed this year and for that number to ramp up to more than 15,500 birds annually beginning in 2027.

Scientists for years have been shooting barred owls on an experimental basis and officials say the results show the strategy could halt spotted owl declines. As of last year, about 4,500 barred owls were killed on the West Coast by researchers since 2009.

Killing one bird species to save others has divided wildlife advocates and is reminiscent of past government efforts to save West Coast salmon by killing sea lions and cormorants. Or when, to preserve warblers, cowbirds that lay eggs in warbler nests were killed. The barred owl removals would be among the largest such effort to date involving birds of prey, researchers and wildlife advocates said.

Barred owls arrived in the Pacific Northwest via the Great Plains, where trees planted by settlers gave them a foothold, or via Canada’s boreal forests, which have become warmer and more hospitable as the climate changes, researchers said.

Their spread has undermined decades of spotted owl restoration efforts that previously focused on protecting forests where they live. That included logging restrictions under former President Bill Clinton that ignited bitter political fights and temporarily helped slow the spotted owl’s decline.