Adult Female Grizzly Bear (Ursus arctos horribillis) Abundance and Distribution in Montana Fish, Wildlife, and Parks Region 2
Bachelor of Science
School or Department
Forestry and Conservation
Faculty Mentor Department
Forestry and Conservation, College of
Grizzly bear, Montana, Abundance, Distribution, Ursus Arctos
Other Animal Sciences
Grizzly bears (Ursus arctos horribilis) are currently listed as threatened under the Endangered Species Act. Their status makes it crucial to understand the population status and trends of grizzly bears in Western Montana. The question we aimed to answer was: How many adult female grizzlies were there in Montana Fish, Wildlife, and Parks (FWP) Region 2 during 2021? To answer this, we conducted an estimate of adult female grizzly bears in Montana Fish, Wildlife and Parks Region 2 in 2021 using photos and confirmed reports. Our study focused on females because they are readily identifiable and are an important indicator of the population’s current and future health, especially females with cubs. Additionally, reports of females with cubs are always recorded by FWP, but reports of male bears are usually not recorded unless there is a conflict. We used confirmed reports, incidental video recordings and photos to estimate the population and examine how this compares with other similar studies. This area is especially crucial to study because Region 2 contains fragments of 3 out of the 6 recovery zones in the lower 48. Our goals were to 1) assess the current number of female grizzlies in Region 2; 2) determine whether the population is increasing, decreasing, or stable; and 3) determine whether the use of human reports and camera footage is a reliable technique to estimate the abundance of a population. Based on previous surveys, we hypothesized that there are about 139 female grizzlies in Montana FWP region 2. However, we knew our estimate was likely to underestimate the actual number of grizzlies as a result of individuals that were not seen or reported during 2021, so we predicted that our actual estimate would likely be fewer than 139. Ultimately, we estimated 29 distinct adult female grizzly bears in Montana FWP region 2, significantly below our hypothesis. While it is possible that grizzly population numbers are declining, our low estimate is likely, at least in part, due to us being unable to account for every single adult female grizzly bear.
Honors College Research Project
GLI Capstone Project
Ruta, Emily E., "Adult Female Grizzly Bear (Ursus arctos horribillis) Abundance and Distribution in Montana Fish, Wildlife, and Parks Region 2" (2022). Undergraduate Theses, Professional Papers, and Capstone Artifacts. 397.
© Copyright 2022 Emily E. Ruta