Hunt with the wind in your face. It's a familiar maxim among hunters, based on a complex collection of scientific facts and theory that's been boiled down to a T-shirt slogan. But for many reasons, it works.

Sight is the primary sense used by humans. A hunter visually locates a deer, evaluates the safety, legality and physics of the shot and decides whether to take it.

But scientists and deer experts believe that when a white-tailed deer reconnoiters its environment, it perceives the world quite differently.

Deer eyes are made for night vision. With fewer of the color detectors than are built into the human eye, deer in daylight probably see patterns of blacks, whites, grays and maybe some neutral color tones, placing a priority on detecting movement.

But through the deer's long nasal passages and a secondary scent organ, they smell a far wider range of information than hunters perceive with their eyes. Hunters who understand how and what deer smell have a better chance of adapting to deer's ever-changing, unseen environment.

"They have so many membranes in their nasal passages that collect scent. It's difficult to fool a whitetail's nose," said Abby Abbondanza, former lead singer of The Povertyneck Hillbillies. Still moonlighting in a solo music career, Abbondanza is a professional hunter for the "Bullseye Outdoor Adventures" hunting show on cable TV's Sportsman Channel (next air dates are in the third and fourth quarter of 2010).

Recent scientific advances enable researchers to chart the properties that mammals, including deer, can actually detect through smell. But Jeannine Fleegle, a biologist in the Pennsylvania Game Commission's deer and elk section, said science has no idea how deer interpret those smells.

"They can smell your coffee, but what does that mean to them?" she said. "In suburban areas and near farms they smell humans every day, but what do they think when they smell a human in a place where there shouldn't be humans? During the rut, when they're focused on reproduction, do they interpret what they smell any differently?"

The shortening of days stimulates the hypothalamus section of a deer's brain, triggering a reproductive phase and activating the vomeronasal organ, which senses chemical compounds that can't be detected by the nose. Bucks and does have the organ.

"You see a lot of tongues out during the rut," said Fleegle. "They're forcing scent up to that organ. We don't know what those nonvaporized compounds are that they're detecting, but they're very small nondissolved compounds suspended in the air."

During the rut, males and females visit scrapes, which are marked by urine and the signature lipid excretions of the tarsal glands, located on the insides of their back legs.

"They're communicating at the scrapes," said Fleegle. "The scent is telling who's visiting the area, the deer's social status, reproductive status and probably other things, too."

Hunters who position themselves just downwind of scrapes during the rut will see more deer. But just as deer communicate among themselves through scent, many hunters unintentionally communicate their presence to the deer.

"I'm a stickler on scent," said Abbondanza. "If you're careless about your hygiene, the deer will know. First thing I do is take a scent-free shower. They actually make a scent-free toothpaste ... some guys brush their teeth with baking soda. I wash my hunting clothes about every three trips, more if they get sweaty. Keep your hunting clothes in a scent-free container and don't put them on until you get to where you're going to hunt."

Once you've minimized your scent, consider wind direction, elevation and the use of masking or attracting scents.

"The deer are going to come into a food plot with the wind in their faces," said Abbondanza. "Position yourself so you can watch that spot from downwind."

Higher stands keep human scents above deer's detection zone. Abbondanza sets his stands higher than usual at 22-25 feet.

While some hunters swear by doe-in-estrus scent, others question what the canned scent of an unfamiliar doe might mean to a buck.

"When a buck goes to a place where a doe has just urinated to asses where she is in her cycle," said Fleegle, "I guarantee it smells a lot different than urine that's been sitting in a bottle for months."

Many hunters prefer masking scents, particularly raccoon and fox.

"That's always a good cover-up -- it'll help lessen the chance of your getting busted," said Abbondanza. "I spray the bottom of my boots when I walk in. I only use doe estrus scent during the heart of the rut -- a week, week and a half window. Because otherwise, you're spooking them."

Awareness of the deer's complex world of olfactory communication can dramatically improve a hunters chances.

"You can't be 100 percent scent-free and you're never going to fool a whitetail 100 percent," said Abbondanza, "But since I started doing this, I see so many more deer -- so many more mature deer."

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