Trouble for coyotes?
Researchers predict that park wolves will have a strong impact on coyotesYELLOWSTONE NATIONAL PARK - On a sunny Sunday afternoon, two coyotes rested on a hill overlooking the Lamar Valley, occasionally glancing over at a group of trees below them and to their left.
"I know why they're there," said Bob Crabtree, director of Yellowstone Ecosystem Studies. "Those coyotes have stopped there and rested there because they can see the pens." He explained that wolves recently brought into Yellowstone are housed in pens nestled into the group of trees.
"They're there because they can smell the wolves, or the wolves' food, or both."
Crabtree and canid biologist Jennifer Sheldon led a group of research volunteers through the Lamar Valley on Sunday, showing the volunteers some of the territory they'd be covering during their week-long stint with the non-profit Yellowstone Ecosystem Studies research organization.
The volunteers will be contributing data to long-term, on-going studies of coyotes, a species many scientists predict will be strongly affected by wolf reintroduction, Crabtree said.
"Biologists generally agree that this will be the species most impacted," he said, adding that elk and bison, the wolves' main prey, will also be affected by a successful reintroduction effort.
Wolves will take over coyote territory, forcing them to the fringes, Crabtree said. Wolves will also claim some of the coyotes' food supply, especially elk calves. As a result, bilogists predict, coyote populations will decline over time.
This is the sixth year YES researchers have been studying coyote pack composition and behavior in Yellowstone. And, based on that information, researchers are already able to detect changes in coyote behavior since the first wolves were brought into the park a little over a week ago.
Crabtree called the coyotes' behavior on the hillside "the first of many, many responses to the presence of wolves."
The coyotes are responding in other ways, as well. YES researcher Sheldon said that coyotes usually vocalize an average of three to four times a day. But packs in the Crystal Bench area, where wolves are now penned, are averaging one yipping and howling session an hour.
So far the wolves, characterized by their lower, slower vocalizations, aren't talking back. That probably means one of two things, Sheldon said. Maybe the wolves just don't care about the coyotes' presence.
Or, she said, perhaps the wolves have not yet formed a cohesive enough group to howl together. Vocalizing is a social activity and reflects a group's unity, she explained. They also might be timid due to their new surroundings.
"This is one of the grand experiments of our lifetime," Crabtree said of the wolf reintroduction effort and the knowledge it will generate.
Captions (scanned photographs will be online soon):
A coyote trots through late-afternoon sunshine in Yellowstone's Lamar Valley. This is the sixth year Yellowstone Ecosystem Studies researchers have been studying coyote behavior, and they are interested in seeing how wolf reintroduction impacts the species. Biologists predict wolves will directly compete with coyotes for territory and prey, eventually driving down coyote numbers in the park.
YES researcher Jennifer Sheldon instructs research volunteers on the morning of their first day in the field. "Citizen scientists," or lay people, donate their time and a fee to YES in exchange for training and a spot on research expeditions. Sheldon said she studies coyotes by direct observation, without implementing radio collars. "We're trying to develop an alternative to the intrusive process of capture, collar, release," she said.