May fawns tell us about the 2022 rut, 'flood the market' and protect the population

Some years we see and hear about fawn sightings early in May. And then other years, as was the case this spring, we see them later.

Fawns started hitting the ground en masse during the middle of May this year. Of course there are outliers, a few fawns that are born earlier and some very late.

The major flush of whitetail fawns varies its timing each year depending upon the previous year’s peak rut, which fluctuates from year to year, up to about three weeks.

So this year's fawn drop points to the arithmetical fact that we had an early November rut last year, which seemed to peak in the Southern Tier of New York state then, flowing into the second week of November, and tailing off through the gun season by Thanksgiving.

Last year (2022) we did experience a minor, secondary rut peak at the end of the first week of December. Of course fawns conceived then have not hit the ground yet, as of this writing.

But sure enough, these witnessed mid-May fawn sightings across the state validate last fall’s rut predictions for an early November rut peak for hunters.

The gestation period lasts about 200 days

The gestation period for the whitetail deer is a fact and spans about 200 days, give or take a few days.

Known variances from the 200-day pregnancy period in whitetail deer are partially due to environmental factors (like a tough winter, or an unusually mild, warm winter), health and age of the doe, and genetic variance.

As we know, a woman’s gestation period is nine months, but children are sometimes born a bit earlier or later than that target date. Recent DNA research has shown us that whitetails often have multiple conceptions.

Recent whitetail studies in fact indicate a significant percentage (25%) of twin fawns, and even triplets have different fathers.

So twin fawns we observe could very well have been sired by different bucks.

In the past, deer researchers had postulated that fawns are always born at the same time each year and used breeding formulations based on fetal measurements, many taken from road-killed doe.

However, questions arose about the veracity of measuring dead fetuses taken from road-killed doe as a way to backdate the rut. Differences in size of the two fetuses may have been in part due to having multiple sires, not to mention the aforementioned health of the doe and winter climate.

Various whitetail fetal studies have shown to have shaky correlations on size related to age.

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Regional climates impact when fawns are born

A mid-November rut produces newborn fawns in mid-May, when many spring turkey hunters are still hunting for the elusive tom.

Though in some gobbler seasons, fawns are seen by gobbler hunters throughout most of May, because on those years we had an earlier peak rut, occurring in late October and the first days of November.

Seems like what works best for whitetails here in the Northeast is when fawns are not born too early or too late.

A severe cold snap, with freezing temps and snow in late April, challenges the survival of early fawns.

And if fawns were born too late, say, past July, they would still be spotted and trying to forage in an early November snowstorm. And their diminutive size makes winter survival in a tough year problematical.

A mid to late-May fawn crop seems about ideal for the Northeast, not too early and not too late.

But other areas of the country have different peak rut dates tuned by their environments and the ecological factors.

For instance, Mississippi has a December peak rut as an ideal date so that fawns are born in late June.

Deer along the Mississippi delta never had to worry about an early or late winter, but instead their fawn drop needed to dodge massive flooding from the Mississippi River.

Sometimes in May, the ”Big Muddy” flood waters historically spread out for many miles in the low country (especially prior to the extensive levee and flood control system).

If fawns were born in Mississippi in May, survival some years would be very challenging.

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Newborn fawns have strength in numbers

Whitetails drop their fawns at nearly the same time and as a result, many predators are overwhelmed by all the fawns.

If fawns were born in a trickle, say at a steady pace through a two month period, predators could put a severe dent in the whitetail population.

Instead, whitetails, in a way, overwhelm northeast predators such as coyotes, fishers and black bears by dropping all their fawns at virtually the same time.

Though many are lost to predation (some studies track up to 50% or more as the attrition rate of fawns in certain areas) many still make it.

— Oak Duke writes a weekly column.

This article originally appeared on The Evening Tribune: What May fawns tell us about the 2022 rut keep populations steady