Photo of SIM deer in spring

Spring 2021 Update about the Southern Interior Mule Deer Project

The Southern Interior Mule Deer (SIM Deer) Project is an ongoing, collaborative multi-year project covering an area roughly the size of a small country in order to collect scientific data on why SIM deer populations are decreasing. The project is a collaboration with the Okanagan Nation Alliance, The University of BC Okanagan, The University of Idaho and the British Columbia Fish and Wildlife Branch. 

The project has a total of 225 camera sites and over 800,000 mapped SIM deer locations (from collared deer) across 40,000 square kilometres, in West Okanagan, Boundary and Cache Creek regions 

The study is unique because the camera trap and collaring data together should provide insight on how highly complex animal interactions and different human-caused landscape disturbances may be negatively affecting the Southern Interior mule deer population. 

Human-caused landscape disturbances include: unusually high density of secondary roads in the Southern Interior of B.C., changes in fire patterns with significantly fewer low-intensity fires in the area (fires are often followed by higher quality forage), cut blocks and more. 

Next year preliminary results from our extensive trap camera research should be available, and by late 2022 the data analysis of collared deer migration, survival, and mortality should be complete. 

Capture and Collar  

We are meeting our collaring goals for all deer age groups and have collected over 800,000 locations, mapping the movement of females and juveniles between summer and winter ranges and landscape features. In the last year, 137 additional adults and fawns have been captured and collared. We have added: 6 adults18 fawns and 21 neonates to the West Okanagan study area; 3 adults, 19 fawns and 20 neonates in the Boundary study area; and 12 adults, 18 fawns and 20 neonates to the Cache Creek study area. Since the program began three years ago, 382 deer have been collared (including deer whose collars failed or fell off as designed).  

We incorporated collaring of neonates into the project more recently. Historically, the technology required for capturing and collaring neonates was prohibitively expensive, but we have implemented very recent methodology in neonate collaring, allowing the project to collect survival data on neonates much more affordably. Data on survival of neonates allows us to more accurately estimate one-year survival rates. The data also helps determine how maternal winter and summer range affects neonate survival (how landscape affects neonate survival).  

 

Survival and Mortality 

So far results indicate adult survival rates are different by region but not by year. To date we have investigated 155 mortalities. Annual adult female survival for the last three years in the West Okanagan was 85%, Boundary was 75%, and Cache Creek was 86%. Average fawn survival for the last three years from December to June in West Okanagan was 64%, in Boundary was 66%, and in Cache Creek was 63%. However, overwinter fawn survival differs by region and significantly by year, and more data is being collected to analyse why fawn survival varies significantly from year to year.   

The collars notify us if a deer has been stationary for 4-6 hours, indicating a mortality. We try to reach that collar location within 48 hours and complete a mortality investigation. If the reason for mortality is clear, we record the cause of death and collect the jaw and femur to estimate body condition and age of the deer when it died. If there is no obvious reason for death (i.e. no predator sign in the area)we conduct either a field or lab necropsy. Deaths are only recorded as “unknown” if there are almost no remains, and no other evidence to establish probable cause of death. 

All female adult and 6-month-old fawn mortalities since the start of the project: 

Mortality Cause Number 

Accident 1
Black Bear 2
Canid 6
Cougar 42
Coyote 8
Drowning 1
Grizzly Bear 1
Harvest 2
Health 2
Probably Cougar 8
Predation 2
Probable Bear 1
Probable Coyote 7
Probably Wolf 1
Starvation 2
Unknown 15
Vehicle 5
Wolf 6

 

All neonate mortalities from the first 15 weeks of life (not included in the above table): 

Mortality Cause Number 

Bear 10
Black Bear 3
Cougar 1
Exposure 1
Health 2
Lynx spp 1
Probably coyote 1
Predation 3
Probably Bear 5
Probably Cougar 1
Unknown 15
Harvest unknown

It is possible to look at these numbers and blame predators for deer population decline, but research shows that in regions of North American where there are no predators, survival numbers are very similar (please watch our Mule Deer Webinar from November 2020). 

Camera Trapping 

In 2020 our volunteers spent 1,450 hours and covered 25,000 km, maintaining and moving cameras, often to some of the most hard-to-reach areas in Southern B.C.  

Between April and June, we will again be moving the cameras to summer range, topping up and replacing batteries, removing data cards, repairing and replacing cameras. The cameras will be moved one final time in the fall of 2021 and collected in the spring of 2022. 

If you’d like to help and enjoy looking at pictures of wildlife, please send an email to samuelfoster@uidaho.edu to help sort the 1,000,000 photos of wildlife taken by our cameras 

To donate, visit BCWF Ways to Give and select Southern Interior Mule Deer Project under designation, and we will issue you a tax receipt. 

Thanks 

The Southern Interior Mule Deer Projects is the largest collaborative wildlife research project in British Columbia. It would not happen without our collaborators, funders and volunteersThis year, we especially want to thank Brian Hancock, David Carleton and Grant Hiebert for their work coordinating 100 volunteers. 

 

 

 

 

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