October 25, 2022
In 1971, Bowhunter Conservation Editor Dr. Dave Samuel penned his first column for the magazine, entitled “Woods and Water.” Over 50 years later, he’s still writing his popular column (long since renamed “Know Hunting”).
The topic of his first article was the need to harvest antlerless deer. This was not a popular topic back then, and it still meets some resistance from hunters to this very day.
Back in the 1970s, many deer herds across the country were managed by buck-only laws. I was 10 years old at that time, yet I still vividly remember the guys in our hunting camp saying, “The state wildlife department is insane if they want us to shoot does. But, if they’re going to issue doe tags, we’ll do our best to fill them because we need the venison!” Make no mistake about it, in many parts of the country, killing antlerless deer was beneath the sportsmanship of many hunters well into the 1990s.
Ironically, 25 years later, one of my first columns for Bowhunter was entitled, “The Basics Of Doe Management.” The ABCs of deer education Dr. Dave was writing about in the 1970s was slowly becoming accepted into the average bowhunter’s mindset.
As deer numbers started to increase across the country during the 90s, so did the number of hunters becoming more selective about exactly what they wanted to shoot. The emergence of quality deer management and the QDMA (now called the National Deer Association) also entered the picture at about this same time, which caused many hunters to advocate for better habitat, healthier herds, and older age classes of bucks.
As a result, the biggest unknown from the viewpoint of hunters was: Just how many adult does should be taken in relationship to the existing habitat? I clearly remember telling landowners and hunters, “Once you shoot enough does that you have scared yourself silly, do me and the habitat a favor and shoot some more!” Although this was sound advice for the vast majority of hunters and hunting properties back then, things started to change in many parts of the country as we entered into the 2000s.
These days, the expansion of coyotes east of the Mississippi has caused many hunters to consider backing off their antlerless harvests — especially in the Southeast. A perfect example is South Carolina, where according to state wildlife officials their deer population is down roughly 27%.
Statistics from South Carolina’s Department of Natural Resources show that between 2002 and 2015 the deer population in the state was declining. According to SCDNR, the overall reduction in deer harvest is likely attributable to a number of factors, including habitat change, long-term drought, two decades of aggressive antlerless deer harvest, and the complete colonization of the state by coyotes and their impact on fawn survival.
Prior to the 1970s, various range maps listed coyotes as a species that lived primarily west of the Mississippi River. Today, most every state in the continental U.S. has coyotes — the Eastern Shore of Maryland, Delaware, and South Jersey might be the last bastions of “coyote free” habitat, but it’s simply a matter of time before that changes.
For reasons still unknown, the expansion of coyote numbers in the Midwest and Northeast has not (repeat, not) significantly impacted deer-recruitment rates. Will this change in the future? Maybe, but this is only speculation.
With fewer adult does available across the landscape, many hunters ask, “Assuming you have an adult doe with two fawns or a single adult doe, which antlerless deer is best to shoot?”
Many biologists would answer, “If you’re trying to increase your deer herd, take the lone adult doe. The reasoning is because if the doe doesn’t have any fawns, she’s most likely a bad mother. Another assumption many of us believed is that a doe becomes a better mother as she increases in age, thus improving her offspring’s chance of survival. Biologists and hunters all “assumed” these two theories were true? But, where’s the data?
As of last year, hardly any data existed. Then, Dr. John Kilgo, from the U.S. Forest Service Southern Research Station, presented a seminar at the Southeast Deer Study Group entitled, “Some Mothers Are Just Better Than Others: Maternal Variation In Fawn-Rearing Success.” Although his sample size of 19 does was relatively small, his findings were very interesting.
Kilgo and his colleagues were trying to determine whether individual does can learn from past fawning experiences in becoming more successful mothers. In other words: Can past success or failure in rearing at least one fawn affect future success/failure in fawn survival?
Kilgo’s data showed that if a doe successfully raised one or two of her fawns, her odds of success in raising future fawns were good. Whereas unsuccessful mothers were almost always not as productive in future years in their efforts to raise fawns to six months of age.
As for older does being better mothers, Kilgo’s results showed, “Although maternal age had a slightly positive effect on future success regardless of past success or failure, odds of future success or failure depended more on initial success or failure. Does that failed during the first year of monitoring were 40% more likely to fail in the future, whereas those that were successful in the first year of monitoring were 22% more likely to be successful in the future.”
In a separate study, Graduate Research Assistant Tristan Swartout from the Auburn University Deer Laboratory monitored the breeding history of 36 does that were present within their facility.
Like Kilgo, Swartout also found variations between does; some does only recruit a fawn every few years, while other does may be recruiting fawns consecutively for up to seven years.
The Auburn data showed that if a doe recruited fawns the year prior, she recruited over 1.4 times as many fawns the next season. Swartout showed 40 mothers that recruited fawns consecutively in their lifetime, which was 47% of all known mothers. However, these 40 females recruited 75% of our fawns from 2008 to 2019.
Some noteworthy mothers within the Auburn facility included one female that recruited nine fawns in eight seasons; one female that recruited at least one fawn for seven consecutive seasons; and one female that recruited five fawns in a two-year span (triplets the first year, twins the second year).
Swartout’s results showed that peak recruiting appears to be at six to seven years of age. This follows other research, which suggested reproductive ability in does peaks at three to seven years of age. Interestingly, the Auburn facility has much older does still recruiting fawns, and 16 known cases of does recruiting a fawn after 10 years of age.
As Dr. Kilgo and Tristan Swartout suggest: If you’re concerned about reduced recruitment or declining deer numbers, advising hunters to consider the taking of antlerless deer only when other deer (and smaller deer) are present may help in determining which does to shoot. The goal is to help hunters tell the difference between successful and unsuccessful mothers. As the data from both studies show, unsuccessful mothers (no fawns present) have a much better chance of remaining unproductive mothers in the future than successful ones (fawns present). If given the choice, adult does with no fawns are the ones you want to target.