WildEarth Guardians based in Santa Fe, N.M., and Project Coyote based in Larkspur, Calif., are among groups opposed to the tournament being staged by Fallon-area ranchers.
Wendy Keefover-Ring of WildEarth Guardians said coyotes play an important role in the ecosystem.
"These kinds of high body-count hunts are completely unethical and go against the spirit of ethical hunting," she said. "They're not going to use the bodies for food or anything else. It's just a waste."
Organizer Matt McFarlane said he doesn't understand the fuss, noting similar tournaments have been held to help protect livestock elsewhere across the West for decades.
McFarlane said coyotes have killed several calves over the last three weeks at his family's ranch near Fallon, about 60 miles east of Reno.
"You're talking about us killing a predator that kills something that helps us make money," he said.
"I don't know why people are making such a big deal out of this. These tournaments been around forever," he added.
Similar events targeting coyotes will be held this weekend in Burns, Ore., and Saturday in Twin Falls, Idaho. The latter derby also will include wolves, foxes and bobcats.
In Fallon, hunters will pay a $30 entry fee, with the pot going to the two- to three-member team bagging the most coyotes Saturday and Sunday. Hunters are forbidden to use bait or dogs.
McFarlane expects about 20 to 30 teams to bag up to 60 coyotes.
"That doesn't put a dent in the coyote problem," he said. "The feds don't have the money to do the killing. They rely on us."