Posted on March 21, 2017

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March column

Editor’s note: Anyone wishing to send a question for future Ask The Deer Tracker posts can e-mail it to, rgbernier@gmail.com

Q. – This past fall while on stand I witness quite a parade of deer one special afternoon. The first deer by was a doe quickly followed up by a mature buck. Both animals were out of bow range. Five minutes later, two more bucks came by with noses to the ground, oblivious to anything around them. Finally, 15-minutes later a spike buck brought up the rear following the gang. My question is how much estrous scent does a doe emit and at what distance can a buck smell that aroma?
D. G. – Akron, OH

A. – A whitetail’s nose is quite remarkable when it comes to picking up scent, but it depends on how much humidity there is in the air to determine the distance that smell can be detected. Once a doe nears and enters estrous she produces a unique scent in her urine that chemically heralds her breeding status. The doe, like a female dog that is in heat, will drip, or spot, as she moves about. Is that enough scent on the ground to attract that many bucks? Yes and no. Understand that the pheromones within any urine quickly evaporate once introduced to the atmosphere. Deer biologist Karl Miller has conducted field research on artificial breeding for 20-years, bringing does into estrous. Collecting vaginal mucus from an ovulating doe, Miller placed the substance in mock scrapes on numerous occasions and to date has never gotten bucks to pay much attention to it. Because a buck cannot follow the exact doe in heat simply by sight, he must scent track her. Once a buck tests the urine deposited by a doe by lip curling and determines she’s about ready to breed, the chase is on. Each deer has an odor unique only to them that is recognizable to other deer. I believe, much like Miller, that as the buck trails an estrous doe he is following the scent left by her inter-digital gland. If it were different it would be nearly impossible for the buck to continue the chase based on spotting, there just isn’t enough dripping. As far as the bucks bringing up the rear, like curious school boys hoping for some action they are following both the doe and attending bucks scent left on the forest floor.

Q. – As a follow up question, does that mean a doe’s urine is the means by which a buck determines her breeding status and is that the key to the rut?

A. – First of all, there are a number of variables that go into the entire rut sequence. The biggest is the hormonal change that occurs in both bucks and does throughout the autumn. With decreasing light, testosterone begins flowing in the males, topping out by November 1. For does, progesterone levels drop and estrogen rises rapidly, especially as she nears estrous. Hormone levels change in urine just as they do in blood. From mid-October to mid-December bucks are indeed urine testers. They are ready to breed from the moment the velvet is peeled from their antlers. Unfortunately for them, the does are not. This prolonged lag in breeding provides for the build up, scrapes, rubs, sparring, fighting, seeking and chasing does. The closer breeding gets, the more a buck will be in a state of perpetual motion. As they cruise through the woods they will stick their nose into every puddle of doe urine they come in contact with and test it. This process is technically called flehmening, whereby a buck draws the urine into two small holes located inside the roof of his mouth. Consequently, when he gets the right scent he will literally go ballistic in an attempt to get to the source of that aroma.
Indeed, urine plays a big role in communicating to a buck the status of a doe, but it is certainly not what I would classify as the key to the rut. To ensure prodigy each year, everything works in concert with the trigger that sets the whole breeding process into motion: decreasing light and the second full moon after the autumn equinox. As far as how far a buck can smell a doe in estrous, it would have as much to do with atmospheric conditions, wind velocity, thermals and location as anything else. As to how much scent that doe emits and whether or not the trailing buck is following that scent alone is something that may never be known.

Q. – It is difficult to admit that last fall I shot a deer during our rifle season, wounded it and failed to recover the animal. I solicited help from three friends and despite our best effort we lost the blood trail. How many people do you feel is ideal when it comes to tracking a wounded deer, or any animal for that matter?
K. H. – Underhill, VT

A. – It is my opinion that four people tracking a wounded deer is far too many for the job. Ideally, two would be all that is needed. You need someone that is quick at picking out subtle details and able to spot blood on any surface. The best way to tackle this is to have the best individual at reading sign to follow the trail while the person behind watches the surroundings for the animal. When you come to a spot where the blood seems to have disappeared, the trailing person stays on the last spot of blood while the tracker does half circles fanning out further and further until the next spot is located.

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