Wolf Recolonization in Wisconsin
by Adrian P. Wydeven, Wisconsin Department of Natural Resources
Updated September 2000
Although population numbers at the time of settlement in Wisconsin are impossible to determine, a reasonable estimate might be between 3,000 and 5,000 wolves, if density of one wolf per 10-20 square miles occurred. This is indicative of densities found in recent years in the saturated wolf habitat of the Lake Superior Region, including Ontario, Canada.
During the 130 years following settlement, wolf populations were eliminated from Wisconsin. Loss of habitat, decimation of ungulate and beaver populations and direct killing of wolves by humans constitute the major factors in the demise of wolves. Wisconsin established a bounty system that lasted from 1865 to 1957. By 1900 wolves remained only in the northern half of the state. By 1950 there were 50 or fewer animals in extreme northeastern and central north Wisconsin. After the elimination of the bounty system in 1957, wolves were granted total protection in Wisconsin — probably the first protection granted to gray wolves in North America. Unfortunately, the effort came too late to save breeding populations. Wolves were considered extirpated from the state by 1960.
From 1960 to 1975, breeding wolves apparently did not inhabit Wisconsin. Only scattered observations of lone wolves and a few pairs were reported during that period. Shortly after the federal protection of the wolf in Minnesota in 1974, wolves began re-establishing themselves in Wisconsin, apparently dispersing from adjacent Minnesota. Therefore, Wisconsin listed the wolf as a state endangered species in 1975, acknowledging its presence in the state once again.
The Wisconsin Department of Natural Resources began formal monitoring of the state wolf population in 1979 through trapping and radio-collaring, winter track surveys and summer howling surveys. From 1979 to 1999, a total of 162 wolves were captured in Wisconsin and adjacent areas in Minnesota. The winter wolf population ranged from 15 to 248 wolves and consisted of 3 to 66 packs. During the winter of 1999-2000 the population was estimated to be 248 to 259 wolves in Wisconsin.
Wisconsin’s wolf recovery plan was developed between 1985 and 1989. A minimum population goal of 80 wolves was set for the state. The goal was to be achieved through public education, increased legal protection and cooperative ventures to maintain quality wolf habitats.
Re-establishment of wolves in Wisconsin depended on the natural movements of wolves into the state and the natural increase in local populations. The population goal was first achieved in the winter 1994-1995 when 83 to 86 wolves were present. The third year of the goal was reached in the winter of 1996-1997. The State reclassified to threatened in 1999, and the federal reclassification process to upgrade wolves as federally threatened started in July 2000.
Wolf populations declined in Wisconsin during the first six years of monitoring. After 1985 the wolf populations began to increase at an average rate of 20% per year (see Wisconsin Wolf Population graph). Several factors have contributed to their recent increase.
Between 1982 and 1986, researchers found 75% of 32 wolves tested positive for the disease canine parvovirus, but only 35% of 63 wolves tested positive between 1988 and 1995. Despite the persistence of diseases such as canine parvovirus, as well as Lyme Disease, and mange, the wolf population in Wisconsin continues to grow. These diseases apparently affect only small segments of the population. Wolf packs average about 3.8 wolves each, and annual pup survival is at about 30%.
The annual survival rate of wolves one year or older was 61% from October 1979 to December 1985. The rate improved to 82% from January 1986 to April 1992. During the early period, 72% of the mortality was due to human causes. Recently it has declined to only about 50% human caused mortality and survival of adult wolves continues to exceed 80% annually.
Hunters sometimes mistake wolves for coyotes. So, Wisconsin enacted a closure on coyote hunting during the gun deer-hunting season in northern parts of the state in 1987. In 1996 a radio-collared female was shot during the firearm deer season in northwest Wisconsin; this was the first radio-collared wolf shot during that hunting season in 12 years.
People kill fewer wolves now than in previous years in Wisconsin. This is likely the result of better legal protection, a significant increase in public education about wolves and the development of the wolf recovery program. Other factors that may also have helped wolf populations in Wisconsin include an abundance of their main food, the white-tailed deer, and an increase in the wolf population in Minnesota, which provides dispersers to Wisconsin.
Wolf depredation on livestock has generally been minor in Wisconsin, with only five verified complaints between 1976 and 1990. As the wolf population continues to rise, complaints have increased. Sixty verified complaints were documented on wolves between 1991 and 19996. These cases involved 37 calves, 1 cow, 10 sheep, 140 turkeys, 46 chickens and 40 dogs (31 killed), and 23 deer (deer farms). Generally, verified losses were reimbursed at 100% of the appraised value, and 9 wolves were captured at depredation sites and transported to other portions of the state.
Between 1996 and 1999, the State developed a new wolf management plan. The plan was approved in 1999, and set a state delisting goal of 250 wolves outside of Indian Reservations. In winter 2000, 239 to 249 of the wolves occurred outside of Indian Reservations, therefore the state delisting process may begin in 2001. The wolf plan sets a management goal for the state of 350 wolves.
Strategies for managing wolves in the plan include: managing in 4 zones, cooperative habitat management, depredation control and reimbursements, continued legal protection, and intense population monitoring.