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Deer rely on three basic characteristics to determine safety: visual observation, cover, and wind advantage. Often, you will find bedding areas on elevations with an exceptional view. This is not by chance, but rather by necessity. A deer’s vision is far superior to yours, and they will position themselves so that any approaching predator can be seen from a distance, typically on their downwind side.
Additionally, deer will take cover and blend in with their surroundings to avoid detection. Cover can be found at the base of trees, along cedar or pine thickets, in heavy brush or grassland, and many other ground formations where they also have sight and wind to their advantage. Cover will often be found near food and water sources that are accessible with small daytime movements, but only if the view and wind provide for it.
Lastly, these elevations and cover areas will also include a wind component that gives the deer an advantage over anything approaching from upwind. With a keen sense of smell, considered to be 100 times more sensitive than humans, deer will often move out of an area long before an approaching hunter or predator gets close enough for the kill.
Success in the whitetail woods for bow hunters typically relies on closing the distance between themselves and deer to less than 40 yards. While much of the clothing and scent technology available today can help mask or hide your odor, there is no substitute for taking advantage of the wind when planning your hunt. A careful hunter will not only consider the wind direction and speed when entering the field, but also understand how structure, terrain, creek and river bottoms, and thermal air currents can contribute to alerting deer of your presence.
Scent and odor that originate from you spread away over distance as they are carried by wind and air currents. This is often referred to as your scent cone. Your scent or odor is merely molecules or particles that emanate from your body and disperse with the wind. These particles are heavier than air, resulting in them settling closer to the ground where they can be detected by deer and other game. Your setup height above ground can make a difference in the distance your odor settles on the ground, and there are also factors like wind speed and direction that help decide where your scent falls. Let’s take a look at each of these to help you become more aware of how your actions impact your success.
Thermal Air Currents
Perhaps one of the last things I learned about air movement, which has become the most relevant to my personal success, is thermal air currents. During the deer season, the warming and cooling of air causes it to move vertically, in addition to the horizontal component caused by wind. The morning sun heats exposed valleys and lower lying areas first, causing warm air to rise from bottoms into cooler wooded canopies or up gradual slopes. This is evident by the fact that frost and dew usually burn off fields first while still present in forested areas. In the evening as the air begins to cool, thermals will force the air down a slope back toward the bottoms. These rising and falling air currents can carry your scent up and down a hillside, leaving you exposed to the sensitive nose of any deer.
For this reason, I subscribe to the Hi/Low theory of hunting. Where practical, hunt higher elevations in the morning, and lower lying areas in the evening. This allows you to get above the thermal currents where the prevailing wind direction and speed are the main considerations for morning hunts, while also taking advantage of deer traffic to elevated bedding areas. By hunting the lower elevations in the afternoon, the thermals can’t carry your scent across game trails that are traversed when deer are returning to food, typically in these lower lying areas. Again, this allows you to choose your setup based primarily on the wind direction near game trails that enter these feeding areas.
Structure and Terrain
Hunters will often select a stand location based on what they consider to be a prevailing or forecasted wind. However, the prevailing wind and resulting wind direction can be different depending on the terrain and structure of the places you hunt. Each component of the forest and field has the ability to resist, interrupt, or redirect the flow of air. For example, dense thickets of brush, especially in full foliage, or rocky formations can block large portions of the wind. This will redirect that moving air mass along the path of least resistance, funneling your scent to the nearest exit point. And, if this volume of air mass is concentrated through a smaller exit, the wind velocity will increase, pushing your scent further out into an opening.
A rolling hillside or field can channel your scent over a distance of small peaks and valleys and move it as much as 90 degrees. Each piece of contour serves as an opportunity to shift the wind slightly over a distance, pushing your scent to places you’d never expect. In the same way that a rolling ball on a sloped surface causes it to arc across a plane, small undulations and changes in ground contour can carry scent in a sweeping arc at varying degrees. This, coupled with thermal currents, can wreak havoc in the field if ignored.
Scent carrying through a timber area is also difficult to follow. While smaller trees provide little resistance to the wind, every tree serves as a divider of your scent over the wooded area. And, larger trees block some amount of wind, allowing your scent to settle behind them, while also dividing your odor across the space. Each point of resistance in the forest provides another opportunity to divide your scent and, much like ground contour, will push your scent cone to wider angles from your position.
Creek and River Bottoms
Air flow never stops around moving water, even on the calmest days. The turbulence caused by the movement of water creates a corresponding downstream air current, along with an upward air flow from evaporation and heat loss. Deer need water everyday, and if you’re not careful about the locations you select that are in proximity of moving water, you could end up passing time watching leaves change color. Just like the thermal air currents and wind we’ve discussed, air movement caused by flowing water will grab particles of your scent and carry them downstream. Each twist and turn of the river bottom provides another opportunity for particles of your scent to be detected along the banks.
High and Swirling Winds
While many hunters avoid the field on blustery days, high winds provide a definite advantage to hunters. High winds tend to keep deer in close quarters for longer periods. They will find places out of the gusting wind where there’s more consistency in order to remain in their comfort zone, and move later in the day when winds typically subside. Making an approach into bedding areas in a strong wind can allow you to close to much shorter distances. Stronger winds will mask most approaching noise and quickly push your scent away, allowing you to be well within shooting distance when movement begins.
Swirling winds can be mistaken for the action of thermal currents. As evening approaches and the prevailing wind subsides, many hunters sense slight changes in wind direction and interpret that as wind shift. The night cooling is drawing air back into low lying areas, and can overtake the prevailing wind, resulting in what you think is a wind shift. Most likely, you’re just another victim of thermal air currents.
So What’s a Hunter to do?
Scout, organize and execute your game plan. Learn how to read satellite and topographical maps of the places you hunt, label the most important features on your property maps (food, bedding, water, browse, mast, etc.), pay attention to wildlife patterns that develop from your trail camera pictures (travel direction, time of day, groups), position your stands and blinds to take advantage of changing weather and wind conditions, and keep a record of your experience afield for future reference.
In the pre-season, visit your preferred hunting locations during various weather and wind conditions and use a powder wind indicator product to see exactly how the wind is reacting. You can also use colored smoke to get a better feel for the effects over greater distances. Pay attention to your scent cone, the spread of your powder/color over distance, and adjust your stand/blind placement accordingly. By taking the time to understand how the wind reacts under different conditions, you’ll be better prepared when the moment of truth presents itself.
A cautious approach to your stand will always maximize your hunt. Avoid walking trails or accesses where the wind can push your scent into bedding areas, or open approaches when deer are still feeding in fields. You may need to cover twice the distance to get to your preferred location, but you’ll never see the deer you bumped out when you go in the wrong way.
Be careful about what you contact in the field and the way you store your gear. Deer can detect your scent from a sapling you pushed out of the way on a trail, the fuel on your boots from the service station, or the coffee you drank before you got out of the truck. Not only do your clothes and gear hold odor particles, but your breath and bodily secretions can also be a dead giveaway. Carry an odor eliminating spray and/or deodorant stick in your pack and use them on your way into and at your setup.
And what do you do when the wind isn’t optimum? The simple answer is to leave. Once you recognize that the conditions are not desirable for a location, it is important to make an adjustment or vacate the area. Once alerted to your presence, a mature deer will recognize the danger and avoid that area for an indeterminate period of time. If repeatedly ignored, deer will change their normal patterns and avoid areas where human scent is frequently detected.
Lastly, use a program like huntLINX from OutdoorTrackerSystems.com to help you organize all of this information and plan for success. Being able enter, save, catalogue, retrieve, and reference your game plan will help you make better decisions about how and where you spend your time afield. Success usually doesn’t happen by chance, and those of us with a better game plan will prevail more often.