When the US government spends money on wildlife, it's usually to protect it. But there's also an agency tasked with killing wild animals — and last year it took out nearly three million of them.

Wildlife Services, which operates under the US Department of Agriculture's Animal and Plant Health Inspection Service (APHIS), is tasked with responding to conflicts between humans and wildlife and to manage invasive populations.

But critics say the agency's methods are crude and not in line with the latest conservation science.

"The whole approach of just getting rid of the perceived problem by killing it is something that this agency has been doing for well over 100 years," Bradley Bergstrom, a biologist at Valdosta State University, told VICE News.

In 2014, Wildlife Services killed more than 2.7 million animals, 1.3 million of which were native, noninvasive species. They included 570 black bears, 322 gray wolves, 61,702 coyotes, 2,930 foxes, and 305 mountain lions.

The agency also killed three bald eagles and five golden eagles using methods like cyanide capsules, neck snares, and foot traps. Accidental kills are a frequent byproduct of the agency's methods. Of the 454 river otters killed, for example, 390 were unintentional, likely during attempts to kill beavers, which can flood property with their dams.

"Lethal methods are used as part of an integrated approach to manage wildlife damage in specific areas where nonlethal methods alone would be ineffective," Lyndsay Cole, assistant director of public affairs for APHIS, told VICE News.

The overall numbers are down from last year, when the agency killed 4.3 million wild animals.

'Their lethal predator control program is particularly inhumane and totally unnecessary.'

But the number of black-tailed prairie dogs, a species that was considered for listing under the Endangered Species Act in 2008, has exploded in recent years. In 2007, the agency reported 18 killed. Last year, it was 15,698. Wildlife Services also destroyed 33,309 of the animals' dens.

Cole says prairie dogs are killed largely to protect airports, where the animals cause damage by burrowing under runways, chewing on wiring, and attracting vultures. Information about why an animal is killed is not provided by the Wildlife Services in its annual reports, which are broken down by state. It also doesn't disclose the date an animal was killed, who reported it as a nuisance, or the specific location of the conflict.

"It really kind of goes to the fundamental problem with Wildlife Services, which is that it don't say why," Amy Atwood, an attorney with the Center for Biological Diversity, told VICE News. "These numbers are in the aggregate, so we can really only guess."

Many of the wolves and coyotes are killed to protect agricultural livestock, Atwood said. According to USDA data, Wildlife Services reported 37,011 incidences of agricultural losses — which includes everything from asparagus to alpacas — in 2014.

But culling predators may not be an effective way of preventing those losses. A 2014 study examining livestock data from 1897 through 2012 found that lethal force against wolves actually increased the odds of a wolf attack on sheep by 4 percent and cattle by 5 to 6 percent. That's likely because killing wolves causes the pack structure to collapse, which leads to solitary wolves looking for food beyond their usual hunting grounds.

"Wildlife Services once again wasted taxpayer dollars killing nearly three million animals last year," Oregon Representative Peter DeFazio, a Democrat, told VICE News. "Their lethal predator control program is particularly inhumane and totally unnecessary."

In 2012, DeFazio called for a congressional investigation of Wildlife Services, alleging the agency is obstinate, opaque, and a questionable use of public funds. In 2014, the USDA's inspector general initiated an internal review of Wildlife Services. The result of that review is still pending.

The agency's practices also seem to clash with the millions of tax dollars spent on ecological conservation. According to a study Bergstrom published in 2013, Wildlife Services is budgeted $57 million, while the Department of Interior has spent $43 million on efforts to protect the gray wolf. Wildlife Services has killed more than 1,500 gray wolves since 1996.

"Some of these are incredibly important species, imperiled species," Atwood told VICE News. "We have millions of dollars in active policies to recover them. It's a completely schizophrenic policy."