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Two things cause lower concentrations of scent; dissipation and dispersal.
Because scent molecules evaporate (dissipate) at different rates (based
on the wind speed, temperature and humidity) the longer it has been from
the time the scent was left the less there is, and consequently the less
alarmed the animals are. Scent left in the air and carried in the wind
is spread out (dispersed) by the action of the wind. The farther scent
is blown from it's source the less there is, and the less alarmed the
animals are.
Sights
Deer depend to a great extent on their sight to alert them of danger.
Their sight allows them to move at night, and during the low light conditions
of dawn and dusk when they feel most secure. While most hunters know this
they have a hard time translating it into whitetail terms because we don't
think in terms of light factors, we think in terms of time of day or hours.
Humans rely heavily on that piece of technology worn on the wrist called
a watch, but deer don't have watches or clocks. So, what tells a deer
what time to get up in the evening and begin feeding and what time to
head back to bed in the morning? Deer do have a circadian clock in their
brains. The amount of chemicals in a particular portion of their brain
allows them to know approximately what time it is. But, although this
clock may tell them it is time to move, the urge to move is overridden
by the need for security. And one of the primary factors that affects
the deer's security is light. Older deer, bucks in particular, usually
wait until the light factor is right before moving. I don't know exactly
what the light factor (or lack of light) is that tells deer when it is
safe to move and feed. But, it is definitely low light conditions resembling
the conditions at sundown and sunrise.
Anything that causes the light factor to resemble twilight or darkness
can cause deer to begin moving. This includes clouds, fog, rain, sleet,
snow and leaves. Yes, leaves. Remember that deer often bed in heavy timber
where the leaves on trees and shrubs provide shade which makes it darker
in wooded areas than it is in open areas. When there are leaves on the
trees deer feel secure in wooded areas and begin moving and feeding a
couple of hours before sundown. But, they don't usually move into low
brushy areas or open fields until the light factor there resembles twilight.
Vegetation
Because leaves have the ability to alter the light factor there is a shift
in deer movement that occurs every fall that most hunters fail to recognize.
Once the leaves fall wooded areas no longer provide as much shade as they
did earlier in the season. Consequently the deer begin to move in wooded
areas and along travel lanes about a half hour later than they did while
the leaves were on the trees. The hunter who has been watching deer appear
at 6:30 along a wooded trail for a week and then plans to hunt the trail
a week or two later can be in for a big surprise. If the leaves have fallen
the deer probably won't show up until about 7:00, which may be after legal
hunting hours.
Available Light
As I mentioned earlier, anything that creates a reduction in the current
light factor, making it resemble twilight conditions, may cause deer to
begin moving earlier in the evening, and staying later in the morning
than normal. These low light factors can cause bucks to make the mistake
that hunters dream of. Clouds, fog, mist, light rain or light snow often
cause deer to move into open areas up to a half hour earlier in the evening
and a half hour later in the morning than normal, which means they may
move during legal shooting hours. While the light conditions affect all
deer they may be different for individual deer. I have kept a detailed
record of individual deer movement times, including the subdominant and
dominant bucks in my area. The data shows that bucks in general begin
to move later in the evening and leave open areas earlier in the morning
than the does.
Travel Route Changes
Because vegetation causes a change in the light factor, leaves, or the
lack of leaves, cause other changes in deer movement patterns. The travel
route of a deer is governed by two major factors, the path of least resistance
and the need for security. Just like humans a deer doesn't normally plow
through hip deep mud, brush too thick to get through, or up extremely
steep inclines. But, this desire to travel in the area of least resistance
is overridden by the need for security. Deer normally travel in areas
where they are not easily seen. This security need is also different for
each deer. Bucks wear headgear and are more noticeable than does, which
makes them more susceptible to being killed and eaten by predators and
man. Because of this bucks usually travel, not on the doe highways, but
on their own routes, often paralleling the doe trails. These buck trails
often wind through heavy cover in gullies, creek bottoms, overgrown roads,
or where they area out of sight of the top or bottom of the hill.
Early in the year when leaves are still on brush and trees the deer feel
secure moving in vegetation paralleling open areas. But, once the leaves
fall deer can easily see the open area and they feel insecure. This causes
them to move farther into cover. After the leaves fall deer often move
later than they did when the leaves were on the trees. This really hit
home with me while hunting a trail that paralleled a road. Early in the
season the deer used a trail about seventy-five yards from the road. During
the week the leaves fell the deer moved to a trail twenty yards from the
road, farther into the woods. I couldn't understand why the deer stopped
using the original trail until I got down from my stand and stood on the
first trail where I could see the cars driving past. When I stood on the
second trail I could no longer see the cars. With the leaves gone the
deer felt more secure on the second trail, which was farther into the
woods.
Wind
Strong winds can carry scents to a deer and cause alarm. Strong winds
can also cause scent to bounce of trees in thick woods, making it difficult
for deer to determine which direction the scent came from. In either case
strong winds make deer uneasy and hard to hunt. Winds between 10 and 15
miles per hour cause deer to seek shelter in areas with less wind. They
stay in low areas, heavy cover or the downwind sides of hills and woods,
where they can smell and determine scent direction better while moving
and feeding. They may not leave their bedding areas during high winds
With their large rotating ears deer hear better than humans, and they
probably hear every sound around them. But, when high winds rattle tree
branches and leaves it makes it difficult for deer to distinguish one
sound from another, and they become nervous. The point is that a deer's
survivability depends on it's ability to smell and hear. When high winds
make it difficult for deer to hear or smell properly they do not move
far from secure areas. When they do move it is usually in areas where
there is less wind and less noise.
Thermal Currents
Thermals, air currents that move up and down the contours of the land,
affect deer movement because they also carry scent. Thermal currents usually
move uphill as the temperature warms during the morning and move downhill
as temperatures fall during the evening. Deer take advantage of this by
bedding on hillsides during the day where they catch scents on the uphill
currents. When the deer begin to move toward feeding areas in the late
afternoon they often move downhill, which allows them to detect scent
on the currents that are still moving uphill. During the night deer often
bed in low areas where they can detect any scents on downhill thermals
currents. As the deer move uphill toward their daytime bedding areas at
sunrise they detect scents on the thermals which are moving downhill.
If you are interested in more hunting tips, more biology and behavior,
click on Trinity Mountain Outdoor News and T.R.'s Hunting Tips at www.TRMichels.com.
If you have questions about log on to the T.R.'s Tips message board. To
find out when the rut begins, peaks and ends in your area click on Whitetail
Rut Dates Chart.
This article is an
excerpt from the Addict's Manual ($19.95 + $5.00 S&H), by T.R. Michels.
T.R. Michels is a
nationally recognized game researcher/wildlife behaviorist, outdoor writer
and speaker. He is the author of the Whitetail, Elk, Duck & Goose,
and Turkey Addict's Manuals. His latest products are the 2003 Revised
Edition of the Whitetail Addict's Manual, the 2003 Revised Edition of
the Elk Addict's Manual; and the 2003 Revised Edition of the Duck &
Goose Addict's Manual. For a catalog of books and other hunting products
contact: T.R. Michels, Trinity Mountain Outdoors, PO Box 284, Wanamingo,
MN 55983, USA. Phone: 507-824-3296, E-mail: TRMichels@yahoo.com, Internet
Site: www.TRMichels.com
T.R. Michels, Trinity
Mountain Outdoors
PO Box 284, Wanamingo, MN 55983
507-824-3296 trmichels@yahoo.com
SS 474-54-8219
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