Excerpt from BCWF 2024 Annual Repot (shared at the 2025 AGM)
The Southern Interior Mule Deer (SIMDeer) project has been collaring mule deer in three study areas since 2018: Boundary, Cache Creek, and West Okanagan. The main goals of the project are to determine the limiting factors for mule deer in south-central B.C. and to provide management recommendations that might increase deer populations. To date, 322 adult females, 297 fawns, and 137 neonates have been captured. The team also measured pregnancy and fetal rates on a subset of adult females and found that 137 out of 146 individuals were pregnant and 78 out of 108 were carrying twins.
PhD student Chloe Wright successfully defended her dissertation at UBC Okanagan in 2024. During the first phase of the project, Dr. Wright found that:
. Adult female summer survival rates were 89 percent, adult female winter survival rates were 93 percent, fawn winter survival rates were 62 percent, and neonate survival rates to 12-weeks of age were 41 percent.
. The predominant cause of death for adults and fawns was cougar predation, followed by coyote predation.
. Both habitat and annual weather patterns were affecting mule deer survival and population growth in southcentral B.C.
. Mortality risk increased in the winter when deer used areas with higher road densities and when they experienced harsher winters characterized by deep snow and colder temperatures.
. Adult deer that used recent burns and recent cut blocks more often had a reduced mortality risk in the summer.
. Drought in the summer increased adult mortality risk.
Her dissertation provided management recommendations to increase mule deer survival, such as reducing road densities on winter range.
Chloe has passed the torch on to PhD student Mitch Brunet to continue work. Mitch is working to leverage existing data from past capture efforts, while incorporating additional data to delve deeper into factors affecting mule deer survival. Sampling key forage plants to map resource availability for deer relative to landscape disturbance has begun.
In 2024, the team continued to monitor 240 adult mule deer and have begun collaring white-tailed deer in the West Okanagan and Boundary study areas. White-tailed deer are an important addition to help understand factors that may worsen effects on mule deer because whitetails are potential competitors of mule deer and could support more abundant predator populations. Our team will continue monitoring mule deer mortality sources relative to nutrition, risk of predation and competitors, and to identify management actions to improve mule deer conservation.
Respectfully submitted by Mitch Brunet
The Mule Deer Camera Project
The Southern Interior Mule Deer camera project aims to better understand how B.C.'s changing landscapes, and our presence on them, can influence mule deer behavior, distribution, and their interactions with other species.
Between 2019-2022, we installed 230 motion-sensing camera sites across 30,000 square kilometres of B.C.'s Southern Interior, with the help of more than 500 citizen scientists, including hundreds of BCWF members. We collected more than 2.6 million images, including half a million images of mule deer alone, and we detected 15 medium-to-large mammal species native to the region.
With this collection, we are now looking into potential mechanisms behind mule deer declines in southern B.C. Focusing on the times that mule deer and other animals are active, we're testing whether deer aversion to human disturbances can create "time traps" in which deer increase the time they spend around major predators to avoid perceived human risks. To address this question, we're comparing the activity patterns of mule deer in disturbed and undisturbed settings and measuring how much overlap deer share with their primary predator, cougar, to determine their risk of encounters.
In addition, we are investigating the drivers underling how mule deer use their summer and winter ranges. We're measuring how topography, fires, logging, roads, and interactions with other species influence where mule deer occur in each season. Data analyses are being completed by University of Idaho PhD candidate Sam Foster. we anticipate completion of the camera project by the summer of 2025.
Respectfully submitted by Samuel Foster
