Friday, December 11, 2015

Yellowstone #wolves: Numbers drop to 100 plus

Written by  Gib Mathers
Yellowstone Wolf Project Leader Doug Smith is pictured with a sedated wolf sporting a radio collar in the Thorofare, part of which is located in Yellowstone National Park. In 2014 there were 104 wolves in Yellowstone, down from 180 in 2003. Yellowstone Wolf Project Leader Doug Smith is pictured with a sedated wolf sporting a radio collar in the Thorofare, part of which is located in Yellowstone National Park. In 2014 there were 104 wolves in Yellowstone, down from 180 in 2003. Photo courtesy National Park Service
 
The wolf population in Yellowstone National Park has declined a bit since its heydays in the mid 2000s.

In 2003 there were nearly 180 wolves in the park. In 2004 the number was down to more than 170, according to a graph in the Yellowstone Wolf Project Annual Report for 2014 by the National Park Service.

In December 2014, there were at least 104 wolves in 11 packs, including nine breeding pairs, living primarily in Yellowstone, according to the report.

From 2009-14, wolf numbers fluctuated between 83 and 104 wolves with six to nine breeding pairs. Pack size in 2014 averaged nine wolves. Forty pups survived to year end, including 17 in northern Yellowstone and 23 in the interior of the park. An average of 4.4 pups per pack (82 percent) survived in the nine packs that had pups, according to the report. 

In the peak year 2004, 90 pups were born, with 60 surviving. In 2007, about 86 were born with more than 60 surviving. In 2014, 50 were born and 40 survived. 

The same number of wolf pups were born in recent years, but not as many reached adulthood, said Yellowstone Wolf Project Leader Doug Smith. 

“Because of density dependence (carrying capacity) we have fewer surviving (pups),” he said.
Wolves remain protected under the Endangered Species Act.

While around 100 wolves were counted within Yellowstone National Park, as many as 400–450 wolves live in the Greater Yellowstone Ecosystem, according to the National Park Service.

Mange

Mange is still rearing its ugly head among the Yellowstone wolf population. Mange, a skin disease caused by parasitic mites, typically causes severe itching, hair loss and the formation of scabs and lesions.

“It’s cyclical,” Smith said. “We’ve got a pack with mange really bad.”
That is the Lamar Canyon pack, he added.

Wolf cuisine

“During late winter (March), a total of 37 ungulate carcasses fed on by wolves were discovered by air and ground teams,” the report said. Twenty-six (70 percent) of these ungulates — 23 elk, two deer and one bison — were killed by wolves. Eight of the elk (35 percent) were calves, two (9 percent) were yearlings, seven (30 percent) were cows, five (22 percent) were bulls, and one (4 percent) was an adult of unknown sex. Wolves also fed on nine bison they did not kill. The proportion of wolf-killed elk that were bulls was low compared to previous years. “The proportion of carcasses that wolves scavenged was high compared to previous years,” the report said.

It is a risky venture for wolves to take down a 1,000-2,000-pound bison, Smith said. 
At this time, there is a large bison population in Yellowstone.
 
The target population is 3,000 bison within the park. Since 2000, the population has averaged 4,000. Right now, there are probably between 4,000-4,500 bison, said Sandra Snell-Dobert, Yellowstone National Park Public Affairs Office in November.

Wolves bide their time and wait for winter to kill bison for them. “It doesn’t take too many dead bison to feed a wolf pack,” Smith said.

Since bears are hibernating, they don’t poach carcasses from wolves during the winter. “In summer, they (bears) steal a lot of food from wolves,” Smith said. 

Dog-eat-dog world

Five radio-collared wolves died in 2014, according to the report. Two were harvested outside of the park, one was killed in an avalanche, one was killed by other wolves, and one was a capture-related mortality.

Wolves are very territorial. Fighting for food/territory is the leading cause of wolf mortality; 60 percent of wolves killed were killed by other wolves in 2014. “They defend (their) turf from other wolves, other packs,” Smith said.

Even humans can unintentionally cause wolf mortalities by feeding them. “We’ve killed two wolves because they were fed (by humans) and they became a nuisance,” Smith said.
 
There was one documented case of a coyote killed by wolves, according to the report. “Coyotes, wolves, overlap economically and socially,” Smith said. Coyotes eat wolf kills. Wolves, he believes, regard coyotes as rivals. Wolves do not eat the coyotes they kill, indicating they are killing coyotes to eliminate competition.

The packs of 2014

• The largest pack in northern Yellowstone was 8 Mile pack (east of the North Gate) with seven adults and two pups. After the death of the alpha male, it was led by a longtime alpha female, according to the report.

• Prospect Peak (overlapped by 8 Mile) had eight adults and six pups. In late October, at least seven members (adults and pups) from the 8 Mile pack joined Prospect Peak, making it the largest pack in northern Yellowstone.

• Junction Butte pack, just east of Prospect, had five adults and three pups. 

• Mollie’s pack (northeast of Fishing Bridge) had six adults and six pups, said the report. Mollie’s pack continued to use Pelican Valley as their core territory, with only one known trip to northern Yellowstone. The alpha female produced six pups, all of which survived to the end of 2014.

• “After producing five pups and establishing a seemingly stable territory, the Junction Butte pack ended the year with uncertainty,” said the report. “Alpha female 870F was most likely injured by Prospect Peak wolves. One pup was killed by the Mollie’s pack, and another pup disappeared in November. The six remaining Junction Butte pups and yearlings then started to spend time with 911M’s group (inside Junction Butte’s territory).”

• Lamar Canyon (south of the Northeast Gate) had two adults and six pups, according to the report. Starting with only a pair of wolves in early 2014, the Lamar Canyon pack increased in size when a female produced a litter of seven pups, of which six lived through the end of the year.

• Canyon pack (east of Canyon Village) had three adults, said the report. “For the first time since they formed in 2008, the Canyon pack’s white alpha female did not produce pups. The small pack wandered widely, and several younger members dispersed.”

• Wolf 755M’s group in Canyon and Cougar pack territory had three adults.
755M continued his wanderings, meeting up with a female from the Canyon pack in late summer and another un-collared female yearling. The trio remained together to the end of the year. The adult female is the fourth female associated with 755M since December 2012, when his longtime alpha female was harvested outside the park.

Wolf 911M’s group (in the middle of Junction Butte pack) has two wolves, said the report. “Both adults had ties to the Junction Butte pack and occasionally spent time with that pack through the summer and fall.” 

• Snake River (east of the South Gate and also occupying Bridger-Teton National Forest) had nine adults and five pups, according to the report. “Having trackable radio-collars for the first time in years, this pack spent much of their time in the south-central portion of the park. They produced five pups in 2014, all of which lived through the end of the year.”

• Yellowstone Delta (east and south of Yellowstone Lake’s southeast arm had five adults and five pups. “This pack began (in) 2014 with 13 wolves and only two working radio-collars. They produced five pups, but by fall one collar was no longer functional and the other was located with a different pack in Wyoming. By the end of the year, tracking this pack was difficult; it is unknown if they still used their traditional territory in the Thorofare, the Yellowstone River Delta area.”

• Bechler pack (in the southwest corner of the park and Targhee National Forest in Idaho) had six adults and four pups, said the report. “In past years, counting the Bechler pack relied on chance observations because none of the wolves were collared. 

During 2014, we assessed pack size using genetic methods on scat samples collected at their den site after the wolves departed the area. This technique produced an estimate of 10 wolves: six adults and four pups. Efforts to collar and monitor this pack will continue.”

• Cougar Creek (occupying a big chunk of north Yellowstone and overlapping 8 Mile and Canyon packs) had eight adults and three pups, said the report. “The Cougar Creek wolves made several extra-territorial movements outside their traditional range, including movement as far east as Hayden Valley and north to Sepulcher Mountain. The pack left the park in November, and 8-year-old alpha male 689M was harvested. Some pack members may have joined the 8 Mile pack as the year ended because numbers were greatly reduced from fall counts.”