When Yellowstone National Park recently released nearly 700 bison captured during the winter after they migrated out of the park, it unexpectedly held back 53 younger animals, the subjects of a proposed and controversial birth control experiment.
The yearling-through-four-year-old bison will remain in the Corwin Springs facility as the U.S. Department of Agriculture's Animal and Plant Health Inspection Service seeks regulatory approval to conduct research to determine whether a contraceptive vaccine can prevent a brucellosis-positive cow from shedding brucella bacteria.
Yellowstone permitted the proposed experiment May 17. Bison advocates are crying foul, calling it a "backroom deal" lacking public notice or involvement.
"It's really a gross experiment," says Stephany Seay, of the Buffalo Field Campaign. "They could do this study on livestock, on domestic bison that are already in research facilities. There's absolutely no reason for them to steal wild buffalo from the public."
Back in 2000, state and federal bison managers specifically ruled out "using birth control to control the size of the bison population," according to the Interagency Bison Management Plan's Record of Decision.
But Lyndsay Cole, the Animal and Plant Health Inspection Service's media coordinator, says the new experiment abides by the IBMP, which covers, she says, "potential needs for research to inform adaptive management." That, she says, includes contraceptives.
"All that we have done at this point is get a research permit from the park," Cole says. "We will have an environmental assessment and public comment, and that's expected this fall."
The 53 bison, and as many as 47 more, will remain at Corwin Springs until then—and perhaps long after.
APHIS would use the contraceptive GonaCon, registered as a pesticide by the Environmental Protection Agency. It's been used to control deer populations.
"I think it's important to note that this is a birth control agent that's used to manage overabundant wildlife populations," Seay says, "and here this is America's last wild bison population, which is ecologically extinct...It makes no sense to inhibit their evolutionary potential."