Population estimate statistically unchanged from last year
Minnesota’s wolf population estimate was 2,655 wolves and 465 wolf packs during the winter of 2017-2018 within Minnesota’s wolf range, an estimate that is statistically unchanged from the previous winter, according to the Department of Natural Resources.
“Subtle changes in wolf population numbers year to year indicate that Minnesota supports a healthy wolf population and the long-term trends demonstrate that the wolf population is fully recovered,” said Dan Stark, large carnivore specialist for the DNR.
The survey’s margin of error was plus or minus about 700 wolves and makes the estimate statistically unchanged from the previous winter’s estimate of approximately 2,856 wolves and 500 wolf packs.
The population survey is conducted in mid-winter near the low point of the annual population cycle. Immediately following birth of pups each spring, the wolf population typically doubles, though many pups do not survive to the following winter. Pack counts during winter are assumed to represent minimum estimates given the challenges with detecting all members of a pack together at the same time.
Survey results suggest pack sizes were the same as last year (4.85 versus 4.8) and packs used larger territories (61 versus 54 square miles) than the previous winter. Although neither individually represented a significant change from recent years, slightly larger pack territories last winter explain the lower population estimate and are consistent with estimated changes in deer numbers in many parts of the wolf range.
“The accuracy of our wolf population estimate is dependent on radio-collaring a representative sample of wolf packs,” said Dr. John Erb, DNR wolf research biologist.
Annual wolf capture efforts are focused on areas for radio-collaring that are believed to collectively represent the overall wolf range, particularly with respect to land cover and deer density. Capture success varies each year, some collared wolves die or disperse, and some radio-collars prematurely fail, creating annual variability in the degree to which collared packs are representative of the entire population.
“Nonetheless, confidence intervals for the past two surveys widely overlap, indicating no significant change from last year,” Erb said.
Although wolf population estimates have been conducted annually since 2012, the portion of the survey that is used to calculate total and pack-occupied wolf range is completed every five years. This past winter’s survey estimated a 9,321 square mile increase in total wolf range from the 2012-2013 wolf population survey; however, the survey results indicated that only about 23 percent of this new area, or 2,175 square miles, was deemed to be occupied by resident wolf packs during the winter of 2017-2018.
Minnesota’s wolf population remains above the state’s minimum goal of at least 1,600 wolves and is above the federal recovery goal of 1,251 to 1,400 wolves.
The DNR’s goal for wolf management, as outlined in the state’s wolf management plan, is to ensure the long-term survival of wolves in Minnesota while addressing wolf-human conflicts. Wolves in Minnesota returned to the federal list of threatened species as a result of a Washington, D.C. federal district court ruling in December 2014.
Visit the DNR website at mndnr.gov/wolves to find the full report, an FAQ and an overview of wolf management in the state, including the wolf management plan.