Biologists at Yellowstone National Park expected the wolf to knock the coyote out of the top dog position in the ecosystem, but not this quickly.
Biologist Bob Crabtree of Yellowstone Ecological Studies has counted 12 coyotes killed by wolves this winter, and says the actual number could be three times higher. All but one of the coyotes were killed near an elk carcass.
Crabtree says a wolf pack kills an elk about every five days. Since the carcasses are too big for a pack to eat in one sitting, it often strays from the kill, then scavengers like coyotes, magpies, ravens, eagles, foxes and badgers move in.
At first, the wolves tolerated the coyotes, merely chasing them away from the kill. But beginning last fall, the wolves seemed to lose patience. Crabtree says the pack would send one wolf out in pursuit of one of the coyotes.
"Coyotes actually defend pretty well against a single wolf," Crabtree says. But then two or three other wolves would come up and circle the coyote. In short order, they had it pinned down and would play tug-of-war with the coyote until it died.
Crabtree thinks studying the effect of wolves on the coyote population could be an important tool for improving Animal Damage Control methods. "I think we need to keep our minds open to this natural control of the coyote situation," he says.