Biologists have been working to restore a breeding population of elk in Wisconsin since 25 animals were brought in from Michigan in 1995.
A herd in the balance
The future of Wisconsin's elk herd rests with its ability to withstand threats like increased predation and continued vehicle collisions. Managers hope to help tip the scales in the elks' favor.
Kathryn A. Kahler
Life for Wisconsin's elk project staff is a mix of hope and harsh realities. Their hopes are measured by healthy cows with a high probability of bearing strong, feisty calves with a better than average chance of surviving to adulthood. Reality is tallied in a growing number of elk killed by predators and a continued threat from some motorists who ignore warnings.
Laine Stowell, DNR's head elk biologist stationed in Hayward, says staff strives to stay objective when it comes to the growth and success of Wisconsin's herd. Yet there is a tremendous measure of fulfillment when they hold a baby calf whose mother and grandmother were held in past seasons.
"We also feel the loss when we investigate mortalities," says Stowell. "At the beginning of this elk year we had about 131 elk, but in the 15 years since elk were reintroduced, we've also documented 151 deaths. If elk didn't die, we'd have over 300 elk now and would have a limited bull hunting season. Most everyone – except people who hit elk with their vehicles – would be happy. But unfortunately, elk do die, and we try to minimize those losses anywhere we can."
Extirpated from Wisconsin in the late 1880s, elk had for decades been considered for reintroduction to the north woods. An attempt to bring them back in the early 1900s was thwarted by poaching. After a favorable study in the early 1990s, and with political and popular support, elks' return became reality in 1995 with the release of 25 wildMichigan elk in a remote area of the Chequamegon/Nicolet National Forest near Clam Lake. They've since been some of the most studied animals in the history of Wisconsin wildlife management.
The first four years of research on the experimental herd were headed up by the late Dr. Ray Anderson, then a professor at UW-Stevens Point. Anderson and his students oversaw the careful research and methodologies that would form the routines followed by today's DNR elk project team. Those first few years, with enthusiastic support from thousands of volunteers and benefactors, saw such success that Anderson, in a 1998 research report predicted that "at the current rate of growth, the herd could number approximately 500 in 11 years."
That optimism has been tempered by a kind of "one step forward, two steps back" reality. Prior to calving, the herd in the spring of 2010 was 131 animals, a far cry from Anderson's prediction. Even so, there is reason for optimism amid elk enthusiasts of all ilks, some of whom look forward to a year when the population reaches a target goal of 200 animals that might allow a limited bull hunting season.
"We are at least a couple of years away from that," says Stowell. "Once we get closer we'll need to establish a hunting education program for successful applicants. An elk that weighs several hundred pounds is much harder to kill than its smaller deer cousin, so we'll need to educate hunters about elk biology and caution them against shooting at multiple targets if they think the first one didn't go down."
Until then Stowell and his crew will continue with the seasonal routines that make up their "elk year" – spring calf-searching, summer habitat improvement, fall bugling observation, winter trapping and year-round telemetry monitoring and mortality tracking.
As an indication of just how important healthy calves are to the herd, elk biologists mark their new year by the day the first new calf arrives. So when hundreds of searchers take to the woods in mid-May to early-June and discover the season's first calf, a new elk year is declared.
Calving season can be a morale-boosting, upbeat time of year for project staff, but how it plays out depends on many factors and can sometimes be frustrating. Typically, around mid-May pregnant cows leave the herd to scout out a calving area. Once they've found a suitable site, they go back to the herd. Several days later, they return to the calving area, become inactive and give birth almost immediately. It's that inactivity – indicated by radio signals from the cow's collar – that triggers the calf searches. Most years the calving season is over by mid-June.
When calves are found, biologists weigh and measure them, assign identification numbers, then fit the calves with expandable collars or break-away collars for bull calves that will fall off when they reach about 1½ to 2 years. These collars allow project staff to track the calves' whereabouts and help determine calf survival.
The spring of 2008 was an especially frustrating calving season with unusually cool temperatures and freezes through Memorial Day that delayed calving by two weeks. Cows that gave birth early never became inactive and cows that birthed later became inactive, only to be searched and found still pregnant. Calves born early in the season were smaller and two were found stillborn, a rarity in the 12 previous seasons. One positive thing about the long drawn-out season was that only two elk were preyed upon by bears (out of 19 calves found), compared to six out of 23 the previous year.
Observations and statistics kept on calving seasons show that the timing of spring green-up is very important to fetus development and health. Elk calves born early in the spring of 2008, for example, averaged 32 pounds — five pounds lighter than calves born later in the season when more abundant forage was available. Calving statistics also allow project staff to establish pregnancy rates, male to female ratios, cow to calf ratios and calf survivorship, all important to assessing the health of the herd.
The early spring and lush green-up of the spring of 2010 produced excellent conditions and an estimated 38 calves were born this year with one of the best male-to-female ratios in the past 10 years. Stowell and his staff were optimistic about calf survival after observing no bear predation by the end of June.
Much of the time from spring green-up to snowfall is spent improving elk habitat. Elk prefer to graze on a wide variety of grasses and forbs found in natural meadows and forest openings. DNR and its partners establish new openings by clear-cutting; removing stumps; disking and planting small one- to three-acre sites; and treating plots with lime, nitrogen or potash to study plant composition and differences in forage quality. Researchers also place forage exclusion cages on treatment and control areas to measure normal plant growth rates and the impact of grazing elk. Such efforts help managers determine where to focus future activities and funding.
The study area consists of a core and buffer range centered where Bayfield, Sawyer, Ashland and Price counties converge. Much of the 288-squaremile core area is federal forest land in the Great Divide District of the Chequamegon National Forest. The surrounding 824-square-mile buffer zone is a mix of national, state and county forest and private land. Within the core range is an X-shaped area of grasses, sedges and forbs kept free of trees and shrubs that until the fall of 2004 was part of the U.S. Department of Navy's Extremely Low Frequency (ELF) Communication System.
These long, narrow strips – each 18 miles long and 33 yards wide – were part of the reason the area was chosen for the elk study. The Navy maintained a large antenna of electrical cables atop utility poles as part of a means of communicating with its underwater submarines around the world. The open area underneath the lines provided almost 500 acres of grazing for the growing elk herd. Once the system was disbanded in 2004, the task of maintaining open space under the ELF lines was left to the U.S. Forest Service and its partners. The U.S. Forest Service mows sections of the ELF corridor on a four-year rotation with a grant for about half of the expenses from the Rocky Mountain Elk Foundation.
The U.S. Forest Service also maintains about 200 acres in about 64 small grassy openings within a quarter-mile of the ELF lines, and several hundred additional acres of small aspen clear-cuts within a 10-mile radius of Clam Lake. The Forest Service helps protect calving and wintering areas frequented by elk by closing several trails to motorized traffic within the study area.
As summer wanes, daylight dwindles and nighttime temperatures start to dip, Clam Lake residents are treated to the echoing bugles of bull elk beginning the annual rut. In both 2008 and 2009, the first bugles were reported on August 25.
Bull elk spend the summer in small bachelor groups that break up when the rut begins. During the rut, which usually runs through early October, bulls polish antlers they've grown during the summer and bugle to challenge other bulls, maintain their harems and identify their territory. Generally, it's the older bulls (five to 16 years old) that establish harems and breed most of the cows.
The 2008 season featured an above average level of bugling and biologists estimated there were about 10 herd bulls with harems – a sign of healthy competition; even greater in 2009 with 12 to 14 harems and an increased number of satellite and sub-adult bulls.
Monitoring the timing, season temperatures and intensity of the mating season gives clues on what the following calving season will look like. If September is hot, with several days in the 90's mid-month, the following calving season will be drawn out with more calves born in late June and early July. If cool, breeding occurs quickly and the following calving season will be early and shorter, most cows giving birth by the first week in June.
The mating season is the period when elk watchers focus on the Clam Lake area. Many visitors come to listen and look for the elk. Dawn is the best time to hear them and most elk focus their activity along State Highway 77 west of Clam Lake.
Winter trapping allows project staff to collar elk that were either never collared (because they weren't found at birth) or that need replacement collars. Over the nine winters they have conducted trapping, project staff have captured or recaptured 403 elk. Data collected during winter trapping provides another independent measurement of population demographics and provides researchers with a greater degree of confidence in their numbers.
It can also rekindle old acquaintances. In the 2007-08 trapping season, researchers recaptured Cow 26, the first elk calf ever captured and collared during the 1996 calving season. She had not been heard from for 10 years since her breakaway collar was shed and researchers were not sure she was even still alive. That same season, trappers captured two of the original released cows – Cows 2 and 18 – whose collars had gone dead two years before. Replacing collars on these matrons helps researchers track their complete life history and build a better population model for the herd.
The following season saw a similar capture that humbled the elk biologists. "On February 22 we captured a cow and calf just a mile and a half west of Butternut," reported wildlife biologist Matt McKay. "We had been frustrated by this group of four cows and one calf for three weeks and finally closed the trap door on four of the five only to have two escape. The remaining prize was a surprise. We had an uncollared calf and Cow 13 – one of the originals. Her collar had been off the air since 2005. For a 15-year-old cow she was in very good shape, jumping the 7 ½-foot high transfer tub door with ease. She was sleek and healthy."
When the signal from an elk's radio collar changes from one beat per second to two beats per second it is believed to be dead and a search begins. As in all other aspects of herd monitoring, biologists keep detailed data on each elk carcass they find. They categorize each cause of death – predation (wolf, bear, other canine or unknown), parasite, vehicle collision, accident, hunter – determine the sex and age of the animal, pinpoint where it was found, estimate the date it died, and record any other relevant information.
Stowell notes some interesting trends over the decade or so of recordkeeping.
Strategies to reduce vehicle collisions with elk include sensors in the animals' collars to warn drivers to slow down when elk are near roads.
"One would assume that bear predation would shift up or down depending on the bear population," said Stowell. "Currently the bear population is quite high in the Clam Lake area with about 1.1 bear per square mile of suitable bear range. But bear predation on elk calves has been relatively constant at about 20 to 25 percent of the annual mortality of newborn calves.
"Wolf predation, on the other hand, has increased significantly. During the first eight years elk were present in the Clam Lake area, we only had three verified wolf predation cases. During the last six to seven years we've lost 46 elk to wolves."
Stowell says they have also seen a shift in how wolves are targeting elk. From 2003 to 2008, elk mortality from wolves was 80 percent male and 20 percent female elk, and the males were mostly older calves or young bulls. "Now it seems the wolves have developed skills in testing and picking out vulnerable calves and cows and are apparently leaving the bulls alone," said Stowell. He reports that during the past two years, 10 of the 19 elk killed by wolves have been female and six of those were of breeding age.
In May of 2009, for example, three cows were killed by wolves, all with a 92 percent likelihood of being pregnant. That summer three calves – all one to two months old – and two yearlings and a 16- to 17-year-old cow were killed by wolves. The trend is especially troubling for biologists who value cows based on their potential for producing calves and increasing the herd.
The second most common cause of elk death is vehicle collision, with 27 verified deaths since 1995. Four years ago, DNR elk biologists launched a three-pronged effort to prevent elk-vehicle collisions. First, they began using a reflective, blaze orange radio collar on cows to increase their visibility during the dark and dusk periods when most vehicle collisions occur. Second, they moved their winter trapping efforts farther away from state and county highways, drawing elk away from roads during the higher risk period of winter. The third and most visible step was accomplished with the help of volunteers and $21,000 in grants from the Rocky Mountain Elk Foundation.
"In December 2006 we installed an elk crossing warning system in three zones at the center of the Clam Lake elk activity area," said Stowell. "Each zone is one-half mile wide and two miles long along portions of State Highway 77 where most elk vehicle collisions had been observed. A flashing light on each of the cautionary highway signs is triggered by the elks' own radio collars when they come within a mile of a receiving station. There are three adjoining receiving station zones spread over six miles of highway where both elk collisions and telemetry have identified high risk areas."
Before the warning system was installed, Stowell said, elk-vehicle collisions had been observed at about three collisions per 100 elk. Two years later that was reduced by half. Despite that progress, project staff have been frustrated by a few motorists who are not as responsible as most others. Since the system was installed, 10 elk have been killed by vehicles within a quarter-mile of flashing warning lights. Four of these have been young cows, one with a blaze orange radio collar, which throughout their lives might have produced up to 48 calves.
Parasites and other wildlife diseases have had an effect on herd health in the past. Collectively, they've resulted in 19 deaths – or 13 percent – of the 151 observed to date, said Stowell. When radio telemetry leads biologists to a dead elk that hasn't been consumed by predators or extensively scavenged, a field necropsy is done and samples sent to wildlife pathologists in Madison. They are tested for chronic wasting disease (CWD), tuberculosis (TB), and brainworm if warranted. No cases of CWD or TB have been found in Wisconsin's elk herd to date. Wisconsin's elk came from the lower peninsula of Michigan where they had coexisted with white-tailed deer and the land snails and slugs that are necessary to the life cycle of the brainworm parasite.
Giant liver fluke (Fascioloides magna) has had a greater impact on Wisconsin's elk herd, although it isn't currently considered a significant problem, due in large part to public education efforts that put a stop to recreational feeding of elk. Feeding created a high concentration of elk in an area that was also frequented by aquatic snails, host species to the fluke. Elk biologists launched a concentrated effort to show the locals the effects of recreational feeding and it didn't take long before their efforts met with success.
"The Clam Lake area residents love their elk," said Stowell. "Upon seeing photos of livers destroyed by flukes, they voluntarily ceased feeding the elk."
Continued monitoring since 2006 confirm reduced incidence of liver fluke, and a 2008 master's thesis by Trina Weiland of UW-Stevens Point appears to corroborate the DNR observations. Weiland concluded neither brainworm nor liver flukes in Wisconsin's elk herd are currently a significant problem. She recommended continued periodic monitoring.
So what's in store for Wisconsin's elk herd? According to Stowell, options are limited to reduce wolf predation on the herd. One method would involve "assisted dispersal" of elk around the 1,112-square-mile elk range, a proposal that was approved by DNR's wildlife policy team in August. Currently elk occupy only 10 percent of the designated range, but the area elk currently inhabit is surrounded by wolf packs that have developed elk hunting skills.
"Probably our best means of circumventing these losses is to help move elk to areas between wolf packs, to areas with smaller size wolf packs, and to areas where the wolves have not yet learned the skills to kill elk. Wolves were present in the Clam Lake area before the elk arrived and it took eight years for them to become expert elk-killers," said Stowell.
"Using information from DNR staff who monitor the wolves, we hope to identify areas with marginal wolf activity. Then we'll designate perhaps 12-15 of the yearling and two-year-old bulls and cows we trap each winter to relocate them within the current range not yet occupied by elk."
Managers hope these inexperienced young elk will be less likely to lead the group back to the current elk range. After they are trapped and collared, managers will hold and feed the elk in an acclimation pen for a minimum of six weeks and release them into the new areas after green-up.
"After five years we would expect to see drastic improvements in distribution and numbers," said Stowell. "Since these animals would have radio collars, we should see within a few years whether or not this technique is successful."
The population goal for the current 1,112 square miles of range is 1,400 elk. That would mean two elk per square mile – or 600 elk – in the core range, and one elk per square mile – an additional 800 elk – in the surrounding buffer range.
"Ultimately our goal is a sustainable elk population," said Stowell. "I don't think we're close to that yet, but we'll continue to strive for that goal. I do not expect that we'll reach 1,400 elk in my lifetime, but I hope the elk prove me wrong."
Kathryn A. Kahler writes for Wisconsin Natural Resources magazine in Madison.