Wolves cut Yellowstone coyote numbers
By Jeff Tollefson
Reuters
YELLOWSTONE NATIONAL PARK, Wyo. – Wily coyote has run into a spot of
trouble, at least in Yellowstone National Park, where the canine once
reigned supreme, until his bigger cousin the wolf came on the scene with
great fanfare in 1995.
Things have not been the same since.
When 31 gray wolves were released in Yellowstone in 1995 and 1996, all the
attention was on the great predators: Would they thrive? Would legal
challenges from ranchers groups fearing the loss of young livestock send
them packing?
Now the legal challenge is settled and the wolves have done just fine,
expanding their numbers to 168 in as many as 16packs. But the biological
effects are reverberating throughout the Yellowstone ecosystem. Coyotes,
long overabundant because of no competition from wolves, have been hit the
hardest, with populations in some parts of the park sliced in half.
” You might think a 50 percent reduction is big, but coyote populations
increased after wolves were extirpated ”
– Bob Crabtree, Yellowstone Ecosystem Studies
“Certainly the species that is going to be impacted the most in the short
term, which I call the first 10 years, is the coyote,” said Bob Crabtree,
founder and science director of Yellowstone Ecosystem Studies, a private
nonprofit research group that has studied coyotes there for more than a
decade.
“You might think a 50 percent reduction is big, and it is, but remember,
coyote populations likely increased in the 1930s after wolves were
extirpated,” Crabtree said.
Since they were reintroduced in 1995, the wolves have already expanded
beyond the boundaries of the 2.2 million acre park, just as they have
taken over territory formerly occupied by their smaller cousins.
No longer top dog
No longer the park’s top dog, coyote populations in an intensively studied
portion of extreme northern Yellowstone have dropped by about 50 percent,
to between 250 and 300, since the wolves returned, researchers say.
In the Lamar Valley east of park headquarters in Mammoth Hot Springs,
coyote packs once averaging five animals each now number only two or
three. Coyote territories in northern Yellowstone have shrunk, with the
wolf now dominating open grassland in the central Lamar Valley, and many
coyotes have been outright killed by wolves protecting their elk
carcasses.
Visitors flock to the Lamar Valley to see the Druid Peak wolves, which
scientists call the most visible and studied wolf pack in the world. More
than 3 million people a year visit Yellowstone and officials say the
wolves are quickly becoming one of the park’s top-draws, often causing
traffic problems when a pack is in view.
Wolf watchers love to catch sight of them hunting and feeding, but a
coyote hanging around for a look and maybe a nibble at leftover elk
carcass can get into trouble.
Once the wolf pack has gorged itself, the animals nap and digest their
meal; raptors and other animals then feast on the remains. But it is a
different story when it comes to coyotes: Wolves are territorial and much
faster than coyotes, even with a belly full of meat, and they have been
known to deal the ultimate blow to many a coyote trying to lunch on
leftovers.
Cars no longer biggest danger
Before the wolves returned, the most common cause of coyote deaths was
traffic, Dave Bopp of Yellowstone Ecosystem Studies said. “Now that the
wolves are here, they kill most of the coyotes,” he said.
” Between wolf territories, coyote populations are doing just fine and
may even in some cases have benefited ”
– Bob Crabtree, Yellowstone Ecosystem Studies
Crabtree said the coyote population has not decreased evenly. In core
areas of wolf activity, the reduction might be 80 to 90 percent, while
less-used areas within wolf territory have seen a 30-50 percent reduction.
“Between wolf territories, coyote populations are doing just fine and may
even in some cases have benefited,” he said.
Bopp said coyotes have apparently learned that roads represent a safe
haven from wolves, who are extremely shy and will do anything to avoid
human contact.
Park Spokeswoman Marsha Karle said some visitors, despite warnings, have
been tempted to make friends with the coyotes, which often show little
fear of people. But feeding animals, as well as calling to animals, is
banned in the park, she said.
“You start getting these beggar coyotes … they hang around the roads
more and they get hit by cars,” Karle said. “They should be eating things
that it is natural for them to eat, rather than Twinkies.”
Coyotes feed largely on rodents, so fewer coyotes should mean more
rodents. Theoretically, that means more food for another canine cousin,
the fox, as well as owls and hawks.
As the presence of the wolf ripples through the food chain, canine
populations should come into healthier proportions, according John Varley,
Yellowstone’s chief scientist and director of the Yellowstone Center for
Resources.
The fox already appears to be prospering, Varley said, adding, “You drop
the pebble in the pool and you watch the ripples, and they go out and go
out and go out, and they seemingly last forever.”