New behavioral research reveals trends

New behavioral research shows that there is more variability in those little spotted whitetail fawns than previously thought.

Observed and recorded variances in the newborns literally have their genesis in that miraculous and complex biological factory called the whitetail doe.

The conclusion is: larger, more dominant does produce larger fawns, partially because the more fit, big doe dominates the choicest terrain and best pickings at the food source.

But that’s not the whole story.

Among other things, new scientific understandings from Mississippi State University have a direct bearing on which doe to shoot to put in the freezer.

Over the years I have generally hunted hard during archery season to arrow the biggest long-nosed doe, figuring mainly that there was significantly more meat on a 140-pound doe than one that would barely tip the scales at 100 pounds dressed.

And the guys at the deer camp down through the years, ragged on anyone that shoots a small deer. You know, “Hey…yuck, yuck, yuck…you could put that one in your game pouch.”

But if that alpha doe produces the biggest fawn, and therefore the largest does and bucks down the line, maybe our old reflex notion of shooting the biggest is counterintuitive, and not so wise or even practical.

Yes, shooting the biggest doe does immediately put more meat on the table. But perhaps the taking of the largest doe diminishes the quality of the local whitetail herd on our hunting properties and we would be better served to, in effect, weed out the smaller ones.

The largest does tend to produce the largest bucks, according to this research.

We know that the variability in fawns at birth is quite dramatic, as baby deer at birth will average from four to ten pounds, according to a spectrum of various researchers.

Outliers, those odd balls in every behavioral study, vary even more. A few fawns, typically birthed by fawns themselves, weigh only three pounds. And then there are the tankers that are over 10.

As in humans, whitetail babies evidence a significant size difference.

In my own family and friends, two twins were born at two pounds apiece while my old employer, a big man, was over 13 pounds at parturition.

Not only does this size difference of fawns at birth give us pause to consider our hunting goals, the fact also discredits the old whitetail fawn measurement scale which determines the date of the prior rut.

Game departments from Canadian providences to certain states here in the USA, along with whitetail deer associations have each sworn allegiance to the 100% accuracy of the fetus measurement ruler. But for the scale to be accurate, it assumes that all fetal fawns are the same size at the same time throughout pregnancy with the same growth rate.

Game departments have measured fetal fawns extracted from road-killed does to determine the date of the prior breeding peak when the fetus was conceived.

Now, after this new research, doubts cloud the horizon on the efficacy of the fetal scale accuracy due to the significant disparity of the size of fawns (not to mention the accuracy of the scale in the first place due to the small selection of pregnant does with known breeding dates killed to measure the fetus to get a timeline base.)

Fawns vary in size for other reasons too, one being they often have different fathers. DNA research has shown that over 25% of wild twins fawns and triplet whitetails have different sires.

Of course there has always been a noticeable size difference between a buck and doe fawn, with the male being slightly larger. Our game camera pictures in May and June show us that.

Some of this newest deer research stretches our common understandings of whitetails and thereby our interpretation of nature itself.

Doe body mass has been shown to even effect longevity in the fawn.

In other words, deer born to big, mature does have a better chance of living longer than those born to those small late fawns; not to mention eventual body size at maturity, growth rate, the probability of reproduction themselves, litter size, and the ability to administer post and pre-natal care.

Expressed in a different way, big mature does are generally better moms and produce bigger and stronger, more dominant fawns that have a leg up on the competition, those not as fortunate, born to younger and lighter mothers, lowest on the whitetail pecking order.

Fawns usually have a sibling, sometimes one and sometimes even two and once in a while three. So fawns are born singly, as twins, or as triplets/quadruplets, hitting the ground en masse, overwhelming their predators.

Sure, a number are gobbled up by coyotes and black bears, hit by mowing machinery, and squashed by cars. But because whitetails rut mainly at certain peaks, the fawns are on the ground in mass floods. A successful tactic indeed.

The last two years, here in Western New York (2017 and 2018,) we experienced two main rut or breeding peaks during hunting season, one around Halloween and one in mid-November.

Since the gestation time for whitetails is always about 200 days, give or take a few, we subsequently had two main flushes of fawns as expected, one hitting the ground in mid-May (reflecting the early late October breeding) and the other in early June showing the result of the mid-November rut.

So if we want to improve our deer herd in a number of ways, according to this newest research, we should seriously consider shooting smaller does, instead of always waiting “for the big one.”

Oak Duke writes a weekly column appearing on the Outdoors page.