Monitoring northeast Washington’s moose population
Eastern Washington’s moose are fairly common and mysterious at the same time. It isn’t unusual to see one in a Spokane neighborhood or park, and sometimes even two or three at a time if a female moose has a calf or calves in tow. But despite being very large, moose are much harder to track down, and count, in the wild.
“Most wildlife surveys are a challenge because you can’t count every animal on the landscape” said WDFW District Biologist Carrie Lowe. “With moose, we are surveying a large and densely forested area for a relatively solitary animal.”
In a typical aerial survey, the Department’s biologists collect counts of moose, both from the ground and from a helicopter, which are broken out by age classes and by males and females, called bulls and cows. These counts are used to calculate age and sex ratios and are paired with harvest data submitted by hunters to glean information about the population’s status and ultimately to set future harvest levels that ensure sustainability for the species.
Sometimes survey data is used to generate an estimate of how many animals are in the surveyed area, though these efforts are significantly more intensive and costly. The last moose abundance estimate like that was in 2016 in the northeast part of the state- the core of Washington’s moose population- and concluded there were approximately 5,000 animals in the area.
“We’ve used a number of survey methods for moose in the past with success,” said Lowe. “We have good tools available, but we also have to keep pursuing improvements to our monitoring, particularly given the changing environment.”
Typically, moose are surveyed in winter months because there’s less cover from deciduous trees and the animals are easier to see on a snowy backdrop. With inconsistent or nonexistent snowpack, aerial surveys become less efficient. Warmer winters can also have detrimental impacts to moose. Their massive body size combined with a thick winter coat enable them to endure frigid temperatures but make warm winters hard for them to tolerate.
To address the challenges of monitoring moose, WDFW is starting a project this winter in Game Management Units (GMUs) 111, 117, 121, and 124. This first year of the project, which begins in early February or as soon as weather conditions allow, involves capturing cow moose via helicopter. Residents in areas where captures take place may notice low flying aircraft during the work.
The primary purpose of capturing moose is to outfit them with a GPS radio collar, which will allow biologists to assess annual survival rates of the species in the study area. The collars will also provide information about how moose use the landscape. Additionally, Department staff will collect samples from the captured moose to estimate pregnancy rates and to evaluate them for disease and parasites, like ticks.
“Our overall goal is 80 collared animals, but we anticipate several years of captures to achieve that level” said WDFW Ungulate Specialist Samantha Bundick. “In future years we’ll deploy additional collars, and the existing collars will help us find moose during surveys, regardless of winter conditions.”
Collars will remain on the moose for approximately six years, after which they will detach.
Over the life of the project, WDFW biologists will combine data from captures, radio collars, and aerial surveys to evaluate the moose population’s performance and identify key factors influencing population status and trend. Ultimately, this effort will assist wildlife managers in setting hunting seasons and harvest levels for moose.
In Washington, the demand for moose hunting opportunities far exceeds the availability of moose in the state. To restrict harvest to levels that ensure population sustainability, moose hunting is only available by special permit to a limited number of successful applicants.
“Moose usually occur in lower densities than other ungulates like deer or elk so we have to be really careful with their harvest,” said Bundick. “The better the information we have, the better we can be at managing harvest to provide ample hunting opportunity while also supporting large and productive moose populations for the enjoyment of all Washingtonians.”
Washington’s moose belong to a subspecies called “Shiras” moose, which is physically smaller than more northern-dwelling moose. Bulls weigh between 850 and 1,100 pounds and adult females weigh between 600 and 800 pounds. During the first half of the 20th century, there were few records of moose within the state. However, moose successfully colonized the northeast part of the state and were considered well established there by the 1970s.
Since then, the population has grown and moose have naturally expanded to other areas. Today the majority of moose in Washington reside in the Selkirk and Kettle Mountains (Pend Oreille, Stevens, Ferry, and Spokane counties) with smaller populations in the north Cascades, Okanogan, and Blue Mountains. In 2022, a moose was spotted as far west as Mount Rainier National Park. Generally, moose prefer forested habitat with alders, willows, and other woody vegetation. They have expanded their geographic range in some states, but most locations include cold winters with seasonal snow cover.
