How long will Washington’s wolf population continue to grow?
Washington’s wolf population has shown eleven consecutive years of growth, according to the Washington Department of Fish and Wildlife’s (WDFW’s) 2019 annual year-end wolf report, released in spring of 2020. But will the wolf population consistently continue to grow, and for how long? Will the state, or areas within it, hit a “saturation” point for wolves? Will there be years when the overall number of wolves in Washington decreases? Experts in the field say we can look to wolf ecology for answers.
A key component of wolf ecology is territoriality; meaning a wolf pack defends a home area and is aggressive to other wolves that enter that area. Because wolves are territorial, and wolf pack sizes are limited by food resources, wolves and other territorial large carnivores like cougars naturally occur at low densities. That means that only so many wolves can occupy an area, and wolves naturally limit their numbers through territoriality (e.g., killing other wolves or driving competing wolves to disperse).
Areas such as the northeast corner of Washington state appear to have reached a saturation point where the majority of the available habitat is occupied by wolf families and fluctuations in numbers are likely to be small. Other areas of the state, such as the southwest third of Washington, have lots of suitable habitat where wolf populations could potentially grow once individuals find and establish territory there.
“As the wolf population begins to recover, we’re going to see population growth slow in parts of the state where the local population is nearing capacity,” said WDFW statewide wolf specialist Ben Maletzke. “It’s a natural occurrence that happens in many wildlife populations and is even more pronounced in a territorial carnivore.”
As of Dec. 31, 2019, WDFW counted 108 wolves in 21 packs. One of the Department’s partners in wolf management, the Confederated Tribes of the Colville Reservation (CTCR), reported 37 wolves in five packs on reservation lands. CTCR changed their methodology for counting wolves recently, so for the 2019 annual count the Department is reporting the numbers separately.
WDFW uses track, aerial, and camera surveys to document wolf populations. The CTCR considers wolves recovered on their lands and didn’t dedicate those same resources to wolf counts this year. Instead, the numbers provided by CTCR for 2019 reflect numbers gathered from hunters, trappers, and public observations, which means they may come with additional uncertainty.
“This means wolf counts will look a little different moving forward,” said Maletzke, “and with the change in methods the number of successful breeding pairs and total wolf numbers may not be as directly comparable to previous years.”
The two counts combined represent an 11 percent increase in the wolf population over the previous year. The counts from 2018 were 97 wolves in 22 packs and CTCR reported 36 wolves in 5 packs. Ten of the packs WDFW monitored for 2019 counts were documented as successful breeding pairs. Using the new methodology, CTCR didn’t collect information on breeding pairs.
While the overall minimum number of wolves in the state was up in 2019 compared to 2018, the number of breeding pairs and packs were slightly lower. This isn’t surprising, according to Maletzke.
“Similar to what we would expect, we are seeing the number of packs and the number of individuals level off in northeast Washington while new packs continue to form in the North Cascades recovery area.”
Two new wolf packs were confirmed in 2019, while another may have disbanded. The new Sullivan Creek Pack formed in Okanogan County. Wolves re-established a territory in the Kettle Mountains, in an area formally occupied by the OPT Pack in northeast Washington. That new pack is called the Kettle Pack. WDFW surveys indicated a single wolf maintained the Diobsud Creek territory this winter, which had been considered the only western Washington pack. Because there is only evidence of a single wolf in that area, it no longer meets the definition of a pack.
There is room for more packs in the state. Historically, gray wolves were common in most of Washington, but today the majority of packs are in northeast Washington, with a handful in the southeast and a few in the central part of the state.
Population numbers will increase as packs fill in between these already occupied territories but eventually those numbers will level off, with new pups mostly balancing the number of wolves that die or disperse during a year.
In 2019, we know that there were 21 documented wolf mortalities: one was killed by a cougar, one died of unknown causes, two were killed by landowners protecting livestock, one killed by a landowner due to a perceived threat to human safety, one is still under investigation, and six were legally harvested by tribal hunters. Nine wolves were lethally removed by the Department in 2019 in response to attacks on livestock.
Once the suitable wolf habitat in Washington is mostly occupied, in a properly-balanced ecosystem the population will become fairly stable. There will be some years when populations are up and some when they are down.
“Even with each year’s natural ups and downs, the wolf population in Washington has grown steadily,” said Ben Maletzke, WDFW statewide wolf specialist. “Yet, we do expect that a time will come when the population will stabilize, and we do not see the year after year growth.”
Since 1980, gray wolves have been listed under state law as endangered throughout Washington. In the western two-thirds of the state, they are classified as endangered under the federal Endangered Species Act and are managed by the U.S. Fish and Wildlife Service. In eastern Washington, they are listed as endangered at the state level and managed by WDFW. More information can be found at wdfw.wa.gov/wolves.