By: Bobby Bond, Georgia DNR Wildlife Biologist
Co-authors: Mike Hooker, Casey Gray and Dr. Michael Chamberlain from the University of Georgia, and John Bowers, Georgia DNR Game Management Chief
In 2012, the Georgia Wildlife Resources Division (WRD), the Georgia Department of Transportation (GDOT) and the University of Georgia Warnell School of Forestry and Natural Resources (UGA) partnered to begin an extensive research project on black bears in central Georgia, the state’s smallest population of bears. This scientific effort was initiated by GDOT’s need to examine the potential impacts of the pending Highway 96 expansion on black bear movements. This provided WRD the opportunity to join the research process without having to fund an entire project alone. Previous WRD research on black bears in middle Georgia occurred from 2003-2006; however, questions remained related to various aspects of the central Georgia black bear population. Specifically, more information on reproductive ecology (female denning, litter size, recruitment, effects of burning, etc.) and population parameters was needed.
Since May 2012, UGA has monitored the movement patterns of more than 40 black bears in central Georgia using GPS tracking collars. Advanced technologies are allowing researchers to locate black bears at a rate as intense as 1 location every 5 minutes. This fine-scale location data is providing insight on how these bears move in relation to Highway 96 between Bonaire, Ga. and Interstate 16. This data also allows researchers to evaluate habitat use across the range of the central Georgia black bear population.
Of the 18 female black bears UGA has monitored in 2014, three (3) had newborn cubs in the den, seven (7) did not produce young this year, and eight (8) females from 2013 should still have yearlings with them from 2013. It’s also noteworthy that 2 of the 3 females that produced cubs in 2014 also produced cubs in 2013 but lost those cubs and thus re-bred. During 2013, litter size averaged 1.9 cubs/litter, whereas during 2014 the average litter size was 1.6 cubs/litter. Typically black bears give birth to around 2 cubs and raise them until they are 2 years old. Litter sizes of 3-4 bears are not typical but do occur. However, most of those larger litters will result in only 1-2 cubs being recruited into the population. Therefore, most black bears only produce cubs every 2-3 years.
Part of this ongoing study was to estimate the population size. Knowing the exact population size is not necessary and is fiscally and logistically unattainable. Wildlife biologists use scientific techniques to monitor a variety of biological aspects of a wildlife population and how these indices inform changes in the population. This is why we use estimated population sizes and indices to manage wildlife populations. The portion of the study to estimate the size of the bear population used barbed wire hair snares and capture-recapture techniques to estimate the number of bears in central Georgia. UGA researchers constructed 129 hair snares throughout the study area (from south of the Houston County Landfill to I-16 in Twiggs County) that were baited. Hair snares were checked weekly for 2 months during the summers of 2012 and 2013, and more than 6,000 hair samples were collected for DNA analysis. Initial modeling results estimate the central Georgia bear population to number ~150 individuals. However, this is only after one year of data collection. A better estimate will be available in the future after a few more years of data collection. Typically, wildlife models get better with additional data.
The next phase of the project will be to move the population estimate research to north of I-16 in Twiggs and Wilkinson counties, primarily to determine relative bear numbers in that portion of the state.
VIDEO: The video shows the UGA researchers crawling into another sow’s den site, the difficulty of getting to it,
the sow’s cubs of the year, and collaring and collecting data from the sow and cubs.