While many hunters were gearing up for the 2021 firearms deer season, agents of the North Dakota Game & Fish Department (NDG&F) were completing aerial surveys of the state’s mule deer populations in the western portion of the state and compiling the data tracking the numbers and health of the state’s popular herd. Unfortunately, a number of factors including lack of forage, lack of cover and a spike in EHD mortality for the state’s muleys likely impacted the results of the survey and well being of the species.
Fawn-to-Doe Ratio Drops
The results of the survey, published in early November evidenced a significant drop in the number of fawns in comparison to the adult does observed in the aerial efforts of the agency. The count of 60 fawns per 100 does represented a more than 25 percent drop over the 82-to-100 observed last year and nearly a third less than the long-term average of 88-to-100. According to NDG&F Big Game Management Supervisor Bruce Stillings, the drought played a big role in both fawning and recruitment shortcomings in the spring and summer of this year.
“We’re finding that this extended drought is going to be just as negative to mule deer and fawn production as those extreme winters that we recently experienced in 2008 through 2010. That lack of moisture resulting in lack of forage which results in mule deer adults being in poorer body condition and those adult does are just not as able to produce a healthy fawn and get them through to six months of age when we do our surveys. Combine that with vegetative conditions from the drought, it has also led
to poor fawning conditions,” Stillings explains, suggesting predation of those fawns was heightened this spring and summer without the usual concealment of healthy grass and shrub cover.
Antler Growth Affected
The number of total mule deer counted in the 2021 survey was 2,163 up slightly from the 2,116 observed in flyovers from 2020 and down from 2019 totals when 2,218 were tallied. The ratio of bucks-to-does was 38-to-100, similar to the 2020 results when the ratio was 36-to-100. However, what stood out to observers counting buck mule deer in the survey was the noticeable decrease in antler size among those males that were 1.5 years old. Where normally these deer would be sporting sizeable two-tine forks at this point in their life, many exhibited just a single spike. This limited antler production
signaled environmental stress and lack of quality forage according to Stillings.
“Typically, a yearling male mule deer will have a nice, forked antler and this year observers recorded more single spikes, more so than normal. This is certainly an indicator of poor forage quality, nutritional stress being put on those younger animals, and producing the single spike instead of a forked antler,” Stillings states, adding this likely won’t impact antler growth ability in the future if conditions improve, “it’s going to be determined and reset based on nutritional conditions this spring and summer coming up in 2022, so it could certainly change for those spikes that were produced this year,” he concluded.
Hoping For Stabilization
While the lower numbers, particularly the fawn-to-doe ratio, are at a low comparable to 2012, coming out of the difficult winters of 2008 through 2011, Stillings and agents of the NDG&F are hoping for a stabilization of that drop in the near term rather than a rebound, as the recovery of populations of mule deer which were seen in 2013 through 2020, often lag and turning counts upward only comes after a few years of population losses, as recent history shows. The impact of EHD also was felt in the state’s mule deer herd this year, despite the species’ better resistance to the virus than the state’s herd of
whitetailed deer which were severely hit by the disease this summer and fall.
“It's going to take multiple seasons of improved forage conditions for those deer to improve their body condition to see the results of better fawn production. For instance, the winters of 2008 through 2010, we didn’t see that fawn production bottom out until actually 2012, and then from there it started going up. So, even with improved habitat conditions, we could still be seeing that lag effect,” Stillings advises.
Spring surveys of the state’s mule deer population will ultimately decide the number of tags issued for the animals’ firearms season in the fall of 2022. However, Stillings cautions that there was a curtailing of tags in 2012 and 2013 following the decreased fall survey results on a similar scale in 2010 and 2011. Such a drop may signal that an already coveted firearms tag for mule deer in the state’s western units will be an even tougher get next year, requiring a longer wait and more preference points in the annual
lottery held each June.
By: Nick Simonson