Radio collars are vital tool for game management

January 27, 2016

by Roger Phillips Idaho Fish and Game Idaho Fish and Game biologist Craig White recently got a message telling him two elk died, but it didn't come from a colleague or a citizen, it was from a satellite. White is Idaho Fish and Game's Southwest Region Wildlife Manager, and he got an email telling him two elk with radio collars stopped moving. A "mortality" signal was relayed from each collar to a satellite and beamed back to the earth, and White was notified. How had they died? It's an important question biologists need to know, so White and his crew loaded trucks, snowmobiles and snowshoes and headed to the Lowman area between Garden Valley and Stanley. Another crew headed by regional wildlife biologist Michelle Kemner drove and hiked into the Boise Foothills west of Bogus Basin. Within 36 hours of getting the email, White and his crew were performing a necropsy on the elk, which is an autopsy performed on animals. They discovered the elk calf was killed by wolves. Kemner's team had to contact several private landowners and get permission to cross their land, but they also arrived within 30 hours and found a dead calf partially obscured by brush after a mountain lion tried to conceal it. They also found two others sets of small tracks, so they suspect it was a female with two kittens. The first few days after an animal dies are critical for biologists to learn the cause of death and any extenuating circumstances that might have affected it, such as if it was in a weakened state from malnutrition, disease or injury. Did one predator kill it and others drive it away and feed on the carcass? Or was a predator even responsible for killing it? "There are a whole bunch of things we can look at that are important to know," Kemner said. "After three or four days, we're losing lots of that critical evidence." Within a few days, a wolf pack or black bears can reduce a carcass to bare bones, and what they miss scavengers can consume, as well as scatter the remains. Mountain lions are notorious for dragging a carcass into rugged, inaccessible places and stashing them so they can return later and continue feeding for several days. When White joined Fish and Game in 2001, traditional radio collars were less high-tech, Back then, he said, biologists and technicians would drive around several times a month and track animals via radio signal emitting from the collars, or fly in aircraft to locate them. When an animal died, unless the timing was perfect, it might take days or weeks to discover it had died and find the carcass. By then, a necropsy was difficult, not to mention smelly, and getting good information on what killed the animal was a challenge. This time, White's crew was there so quickly they could see tracks, and even drops of blood in the snow where a chase occurred. And in an unexpected coincidence, the same pack of wolves had killed a cow elk nearby, and that cow had an ear tag. It had been radio collared in 2009, and collar dropped off the animal about a year later, which it was designed to do. Looking back through Fish and Game's database, White discovered the cow elk was 14 years old when it was captured, collared and tagged, which meant it lived to age 20. White said it's uncommon to have to have two mortality signals on the same day, but he expects more out of the 130 collared elk in Southwest Idaho because winter is typically when most die. Radio collars allow biologists to use signals and/or satellites to monitor animals across thousands of square miles. Modern radio collars blend old and new technologies by sending radio waves and Global Positions System (GPS) signals so Fish and Game personnel can track animals and monitor them from afar, and collars also let computers do some of the most labor-intensive and previously costly work. Fish and Game currently has hundreds of animals radio collared throughout the state. Collars give the department the ability to simultaneously track different animals across all types of terrain during in any weather conditions, year round, and track individual animals for years in some cases. They're an important tool for ensuring the state has healthy, sustainable wildlife populations now and into the future. Wildlife mortality from malnutrition, predation, accidents and disease is expected. What is critically important is the rate at which animals die, and what causes may restrict a population from remaining abundant and healthy. Radio collars make it easier, safer and cost-effective to identify important pieces of information. "It certainly has improved the quantity and quality of the data," White said. Deer In 1998, Fish and Game started intensively using radio-collared deer as a cornerstone of its mule deer management program. Fish and Game currently has about 400 deer with radio collars across 33 hunting units in the state. About half of those are fawns born last spring. Winter is their most vulnerable time of year, and fawns are the first animals in the herd to die during a tough winter. Fawn survival typically determines whether a herd is growing or decreasing. As a rule of thumb, if at least 45 percent of fawns survive winter, the herd will grow, and with less it will decline. Each winter, crews across Idaho capture deer, and their goal is to put collars on about 200 fawns and enough does to offset the number of radio-collared does that died the previous year. Because fawns are growing so fast, collars are designed to detach and fall off so they don't eventually choke the deer. Knowing how many fawns and does survive winter helps biologists know whether they can offer more hunting opportunity, or cut back on the number of antlerless tags offered for fall hunts. Elk Elk are less prone to winter kill than deer, but Fish and Game still needs to know how they're faring throughout winter and whether herds are growing or decreasing. That's why last year, Fish and Game started a similar project with radio-collared elk in six areas in different parts of the state, including different habitat types, and different predator densities. This year, it added two areas, one in the Frank Church/River of No Return Wilderness and another in the Diamond Creek area of Eastern Idaho. The project includes putting radio collars on 30 adult cow elk and 30 calves in each of the areas. When the elk are collared, Fish and Game personnel also check their body condition, conduct a health and disease assessment and determine whether cows are pregnant. "In these first few years, we are keenly interested in the causes of mortality," said Jon Rachael, Fish and Game's state wildlife manager. Knowing how elk die helps biologists understand what's driving or limiting elk populations in the different areas of the state. If animals are in poor condition and a small percentage of calves are born and survive through their first year, it could signal problems with habitat. If elk are healthy and habitat is good, but herds are shrinking, predators may be the limiting factor. If it's predation, information on which predators are involved is also needed. While wolves are often thought of as the primary elk predators, data gathered with the help of radio collars have shown mountain lions and bears are also effective elk predators. Rachael said bears typically prey on newly born elk calves because the two often inhabit the same areas during spring, and newborns are a fairly easy source of protein for hungry bears coming out of hibernation. But within a few months, elk calves can elude bears. Then predation tends to turn toward wolves and/or mountain lions. Since wolves were reintroduced, many folks have overlooked the proportion of elk killed by lions. In several areas of the state, mountain lions led wolves in elk predation last year. Biologists suspect that could change seasonally, so it may take two or three years to understand which predators are responsible, and whether predation is a limiting factor for growing elk herds. If wildlife managers learn predators are driving elk populations below the department's objectives, and they know which predators are most responsible, they can adjust hunting seasons, bag limits, etc. to reduce the predator population in that area. Using data from radio collars also allows game managers to respond quicker to population changes. In the past, aerial surveys were the department's best tool for surveying herd sizes and understanding population trends. Surveys are still an important tool, but aerial surveys are only done every three to five years in most hunting units because of cost limitations. Monitoring radio-collared animals allows Fish and Game to monitor populations every year. "The real strength in using this different type of data is to improve our ability to predict deer and elk population sizes between aerial surveys," Rachael said. "These tools let us do that much quicker than in the past, which allows us to be much more responsive to changes." While surveys can determine what direction populations are heading, they can't explain why, so monitoring radio-collared animals is key to understanding changes. Wolves Many wolves have been radio collared since they were reintroduced into Idaho in 1995. Fish and Game currently has collars on about 75 wolves, and crews are in the process of adding about 20 more this month. Radio collaring wolves provides valuable information about these nomadic animals that's important to know for both population estimates and the knowing where animals gather during key times of year, such as denning, birthing and raising pups. Fish and Game estimates conservatively that there were about 770 at the end of 2014, and the counts for 2015 will be tabulated by April. The animals are spread across most of Idaho from the Canada border south to the Snake River Plain. Tracking wolves across that vast area is extremely difficult without the aid of radio collars. The collars help biologists know where to find wolves, and in some cases, help locate those responsible for killing livestock; a rare-but-important use of radio collars to ensure targeted removal of offending animals. Radio collaring wolves is time-consuming and labor intensive, and like other animals, there's annual wolf mortality, including those wearing radio collars. In addition to focused efforts to radio collar wolves, Fish and Game takes advantage of incidental encounters with wolves during routine deer and elk capturing each year to radio collar enough wolves to offset those that died, or were killed, the previous year.