Grant targets boosting mule deer numbers

bucking trends: OHA grant funds will be used for predator control on lands in areas where the Oregon Department of Fish and Wildlife is implementing its Mule Deer Initiative to restore declining mule deer populations in Oregon. Photo/JIM WARD

The Animal and Plant Health Inspection Service, also known as APHIS, conducts aerial control of coyotes as part of its mission to protect livestock in Eastern Oregon from predators. Because the aerial control program takes place between fall and spring it benefits big game by thinning coyote numbers on deer and antelope winter range and during fawning and kidding periods.

“OHA is concerned about the impact high coyote populations have on deer and pronghorn fawns,” said OHA President Fred Craig. “Studies have shown mortality in newborn fawns of both species to be significant when coyotes are present in high numbers. Considering the current low mule deer population it is critical that we do all possible to help them recover.”

Roaming the Western landscape for many thousands of years, mule deer numbers have declined throughout their range over the past several decades for a variety of reasons including predation, competition with elk, disease and habitat changes. Mule deer populations reached a high in the 1950s and ’60s, then began a slow decline across the West, including in Oregon.

The most recent decline in Oregon occurred in the early 1990s, due to a combination of hard winters and summer drought from which their populations have not fully recovered. In response, the Oregon Department of Fish and Wildlife is implementing a program, called the Mule Deer Initiative, to take a variety of actions intended to stem the downward trend in mule deer numbers and bring the herds back up to management objectives.

Five wildlife management units in Eastern Oregon have been designated as part of a pilot program where factors limiting mule deer populations will be identified, and actions implemented to reduce those factors. The five areas include the Heppner, Murderers Creek, Maury, Warner and Steens Mountain wildlife management units. Action plans are being developed for each of these units focusing on harvest and hunter management, competition from elk, diseases and parasites, law enforcement, public outreach and predation.

Predation is a particularly important factor in mule deer mortality. While cougars have an impact on big game numbers, coyotes can be a particular problem during the spring by preying on mule deer fawns before they grow strong enough to outrun them, and in the winter when deep snow may make escape more difficult.

Research has shown that reducing coyote numbers during fawning periods can substantially increase fawn survival. In some cases fawn survival has increased from about 30 fawns per 100 does to more than 50 per 100. In Utah’s Henry Mountains, two years of aerial and ground control of coyotes to protect fawns resulted in increasing the local mule deer herd by 600 animals and reversing a five-year decline of that population. In another case in Utah, coyote removal during fawning season boosted fawn production by more than 2,000. Similarly positive results were documented in Oregon in the 1970s by a coyote control program in the Steens Mountain Wildlife Management Unit.

“We proved in the Steens that if you have the right conditions you can substantially increase fawn recruitment by removing coyotes,” said Lakeview-based ODFW district wildlife biologist Craig Foster.

Those conditions include terrain that is open enough to effectively target coyotes from an aircraft. In addition, Foster emphasizes that since aerial coyote control is expensive, it is most effective when it targets specific areas where predators are causing problems rather than attempting to cover large expanses of the landscape.

That predator control concept is built into the Mule Deer Initiative. “One of the reasons the Warner and Steens Mountain wildlife management units were chosen to be in the Mule Deer Initiative is because we have had poor fawn recruitment in those units for a number of years,” says Foster. Both units are located in the southeastern part of the state.

For example, mule deer numbers in the Warner unit is averaging about 30 percent below ODFW’s management objective. Currently, there is a wintering population of about 1,800 animals while the target number is 5,500.

Foster emphasizes that it is not known at this time whether those low fawn recruitment rates are due to predation or other reasons. Wildlife managers will look at predation, along with other factors such as habitat conditions, road densities and hunter harvest levels. The portion of aerial coyote control program funded by OHA and conducted by APHIS will target areas where mule deer are being impacted by predation.

“Hopefully,” says Foster, “we will be able to get the mule deer population back up to levels where they can withstand predation and bad weather cycles and will begin to respond to our habitat improvement projects and other management programs.”

APHIS agents removed 1,621 coyotes while flying 362 hours during the 2008 – 2009 aerial control period, which lasted through early July of this year. This season’s control program will begin in October.

The Oregon Hunters Association is the state’s largest pro-hunting organization, with more than 10,000 members and 27 chapters statewide. Its mission is “to provide abundant huntable wildlife resources in Oregon for present and future generations, enhancement of wildlife habitat and protection of hunters rights.”