1/22/2016 2:44:30 AM
Polar Bear Body Condition Index
Can you tell how healthy a polar bear is just by looking at it? How do you describe how fat or skinny a bear is?
Polar Bears International, in collaboration with partners, has developed a Body Condition Index (BCI) card to help answer those questions.
Bears need stored fat to survive and reproduce, and fat is indicative of overall health and condition. It's hard to quantify how much fat a bear has in the field without handling the animal and having the right technology at hand.
That's where the BCI comes into play. The BCI provides a standardized way to rate bears in the field through visual observation, and in some cases palpation, or touch (if they are safely sedated!). Over time, records of body condition across years and regions will help us monitor individual condition, as well as how broader populations may be affected by large-scale environmental change, including loss of sea ice due to climate change.
The original project was conceived by PBI collaborator Diana Weinhardt and completed in conjunction with Steve Amstrup and Geoff York when they worked for the U.S. Geological Survey in 2007. (Both Amstrup and York now work for PBl.)
"After hearing suggestions for improvements over the ensuing years, I led an effort to revise the card in 2015," York said.
The BCI is based on veterinary body condition cards common for livestock and domestic pets and informed by a paper on body condition by Ian Stirling, Gregory W. Thiemann, and Evan Richardson.
In the abstract to the paper, Quantitative Support for a Subjective Fatness Index for Immobilized Polar Bears (Journal Of Wildlife Management, January 2008), the researchers wrote, "Our data demonstrate that the FI (fatness index) rating accurately reflects overall body condition, regardless of polar bear age, sex, or nutritional phase. We suggest that continued field use of the FI rating could provide valuable information on ecological effects of large-scale environmental change on polar bear populations."
York worked with wildlife illustrator Emily Damstra and a team of volunteer advisors from the International Union for the Conservation of Nature/Polar Bear Specialist Group . They used photographs of wild bears from several regions and in various body conditions to refine the illustrations.
The initial audience was research scientists in the field—the BCI helped ensure that everyone was using the same criteria to assess polar bears across their range. That audience has grown and now the BCI is used by hunters, polar bear deterrence staff, Arctic workers, Arctic visitors, and is available for use by Arctic residents.
PBI will use the card in our Body Condition Project—a program to gather information on the body condition of polar bears during the Western Hudson Bay migration each fall.
To the back of the card, PBI added a bear safety primer. "The bear-safety aspect targets visitors to polar bear country as part of our ongoing efforts to reduce bear human conflict," York said. "We have also made the revised BCI card available to government partners for use in their own outreach efforts and under their own logos."
In areas where polar bears are still legally harvested by Arctic peoples, many governments collaborate with hunters to obtain biological samples and other information, such as body condition, from harvested animals. The BCI card is also useful for people working or recreating in polar bear country in an effort to provide more significant information to bear encounter reports.
BCI collaborators and advisors
Geoff York, Polar Bears International
Steve Amstrup, Polar Bears International
Andrew Derocher, University of Alberta
Marty Obbard, Ontario Ministry of Natural Resources and Forestry
Todd Atwood, U.S. Geological Survey
Eric Regehr, U.S. Fish and Wildlife Service
Kristin Laidre, University of Washington
Ian Stirling, University of Alberta
Gregory W. Thiemann, York University
Evan Richardson, Environment Canada