Northeast: Late fawn drop validates last season’s mid-November rut

Sean Wuller | June 3, 2015 | Hunting Land Whitetail Hunting

Last fall hunters in the Northeast felt the whitetail rut was delayed by a few weeks.  This spring they are being proven correct as the fawn-drop seems to point toward a mid-to-late November conception.  The following is taken from the Wellsville Daily Reporter in New York.

Fawn 300by: Oak Duke, Wellsville Daily Reporter

Spring turkey hunters this year have not noticed whitetail fawns to the degree that they often do in May. Is there reason to be concerned?

Where are the fawns?

Last gobbler season (in 2014), hunters took note and chronicled many fawns as we hoofed it through the springtime woods in our pursuit of the elusive tom.

The annual fawn drop date each year points towards an irrefutable fact that the whitetail rut’s peak varies from year to year as much as three weeks.

The sudden flurry of fawn sightings last May across the state validated those rut prognosticators who noted the 2013 season rut peaked early, near the final week of October, about the middle of the short (compared to other states) New York state archery season, around Halloween.

But last fall (2014), the whitetail rut or breeding time, peaked in mid-November, just at the tail end of the archery season and during the beginning of the NY Southern zone rifle season. That’s about three weeks later than the prior year.

The gestation period for the whitetail deer is about 200 days, give or take a few. Like most mammals and women, parturition, or birth is not set by a perfect biological clock that synchronizes perfectly from individual to individual. Some doe drop their fawns in 205 days, others in 199.

A known variance from the 200-day pregnancy period in whitetail deer is partially due to environmental factors (like a tough winter, or an unusually mild, warm winter;) health and age of the doe, and nature’s variance. So 200 days is about average.

As we know, a woman’s gestation period is nine months, but children are often born early or later than that target date.

New DNA research has really thrown a curve ball into the basic two-dimensional computation of fawn birth! Toss in multiple conceptions. Recent whitetail studies indicate a large percentage (25 percent and up) of twin fawns, and triplets have different fathers. And many were conceived on different days.

So when we say that does drop their fawns seven months from conception is about as fine-tuned as we can get.

(It needs to be mentioned that the cloud of questions hovering over the vaunted fetal aging studies, has one more significant modifier now, thanks to real DNA science.) Fetal aging studies measure the fetus and compare it to a known scale to determine fetal age, and then backdate to determine the timing of the prior rut.

A number of state agencies and deer groups believe in the results of the fetal aging method and determine hunting seasons accordingly; despite the preponderance of questions that have proven the fetal measurement conclusions are suspect.  For the rest of the story…