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HomeArticlesKevin A. GardnerThermal PursuitThermal Pursuit

Author: Kevin A. Gardner

In past articles we have covered a variety of topics that affect animal movement and survival such as barometric pressure, food and nutritional requirements, even migration and redistribution techniques that wildlife use strategically. All of which, when sequentially analyzed and fully understood, start to point us in the direction we need to go to find what we seek. These variables, as it were, are all pieces of a large puzzle that can be constructed, and when put together correctly, allow a full understanding of what is going on around you in the outdoors. One really big and intricate part of that puzzle that we have not yet covered is the variable of weather or climatic conditions and how those conditions affect all activity.

When referring to weather or climatic conditions, wind, rain, sleet, snow, heat, up drafts, down drafts, and so on, play a big role in where and when animals will hold themselves. These weather conditions, as they interact with the terrain, create conditions for wildlife that range from fair to unbearable. The prevailing conditions and their fluctuations within a specified area are referred to as the areas Thermal Dynamics. Thermal Dynamics are not necessarily referring to heat or the process of insulating from heat, although that is the most common perception. When animals seek shelter from thermal conditions, these areas become what are referred to as areas of thermal cover.

Even in the blistering heat of summer, when an animal takes refuge in a shaded area, the animal is utilizing the areas thermal dynamics, only in this case it is thermal cover to escape heat. While in this refuge from extreme heat, the animal is still experiencing heat, just at a much lesser temperature than that from which it came. Ambient (surrounding) or prevailing conditions are measured in degree’s of thermal heat, even if in negative Fahrenheit units. To clarify, thermal cover, is meant to describe areas providing either heat retaining or cooling conditions, through naturally insulating vegetation as required to counter degrees of ambient temperature.

Having an idea of an area’s thermal cover density is essential to understanding how necessity will play out for the animals that reside in that location. It may seem a challenge to believe that wildlife will rationalize the use of thermal cover extremes as to not place them into a situation they cannot survive in, but it is true. We are told how important food, water and cover are, and that is also the truth, but indeed too much thermal cover area is equally as bad as too little.

Animals can identify an area that may have too much cover in winter and not enough in the summer and react by moving accordingly as to not place their food and water sources out of reasonable reach. What is a reasonable reach is dependent upon how much energy resources the animals have available at that time to expend. Those resources become quite obviously less as winter progresses and fetal growth plays on energy reserves and agility. Determining the thermal value of an area to animals can be as simple as getting out in the weather extremes and learning how cover is utilized when weather fronts approach, stall and eventually pass. Imagine the value of knowing how your herd reacts in each of these situations.

Exploring movement through analyzing things like tracks and scat piles during adverse conditions will reveal how animals react to prevailing variables and will point to how and to what extent available thermal cover is used. There is no substitute for this exploration as it is the best teacher and guide to knowing when and where to look for animals at any time of year. This is how you learn things about an area, for example, the velocity of winds as they pass through. Wind is such an important aspect of thermal dynamics, in that it can be a bigger detriment to some animals than extreme cold, but in turn can be needed as much or more by the same animal

An animal that is suspended above ground by a set of long legs is more susceptible to wind and wind velocity depleting valuable body heat, than one with shorter or no legs at all. The less cold air passing over, under and around the animal lessens the dissipation of valuable body heat. To the opposite, during hot summer months, wind helps cool the animal and keeps bugs and other parasites moving along and not plaguing birthing and antler growth processes. Another double-edged sword effect in winter is that this potentially dangerous wind is such a valuable resource to the animals that a void of it would also be detrimental. A lack of wind to blow away new snow causes unmanageable snow-pack that covers needed food, and requires greater resources to reach it. As with everything in nature, another great example that there needs to be a balance for a habitat to thrive.

To simplify, big game animals need a combination of thermal cover and open, windy areas within reasonable proximity of each other. This is especially true of grazers that rely largely on being able to paw down to ground vegetation as a food source. You will experience a higher success rate of studying them if you understand that this is the mindset of a deer in the more extreme months of winter.

It is also not a challenge to predict that when animals like deer take up this type of complacent behavior in such a limited or confined area, how vulnerable they can become to competition, even within the herd. This niche area essentially becomes a wildlife preserve in itself, being essentially a confluence of the best available conditions that create the habitat. The same conditions deer need to survive are also the required habitat of all kinds of animals. Think about exactly how many of these type of “special” areas may exist in your hunting region. I would venture that realistically the number is pretty few, but every area has them.

These areas also become key hunting areas for all predators during cold and challenging times. There will be greater pressure on every living thing in the area to not only find enough food, but to not become a food source. Spring thaws will reveal the drama that had ultimately played out as the result of many animals living within a close environment.

When studying an animal that is a ruminant, such as elk, you should understand that they will have the ability to lengthen the distance between the food and cover source. By design the animal can continue to get nutrients from food consumed at periods many hours earlier, as stomach contents are regurgitated and chewed further to break down fiber and absorb nutrients through saliva. This facilitates greater mobility and lessens the need for food and cover adjacency.

Another example of animals using thermal dynamics is that during the winter months in North America, the earth shifts in such a way that south facing slopes get the greatest amount of sunlight and the least exposure to incoming fronts. These areas provide another excellent location to find animals during the days immediately following heavy snowfall periods. Animals are spending a great deal of the late winter and early spring months in these areas during key periods of gestation, lactation and for the males, the beginning of new antler development. With this information, you can plan an approach for observing a herd or seeking cast antlers as spring approaches.

As snows melt, the uncovered food sources that were passed over during the hay-days of fall are now seemingly succulent buffets as the animals follow the retreating snow-line. Once again the traditional areas can become riddled with activity as animals start to redistribute themselves back to areas they occupy most of the year.

Bucks and bulls further pull themselves away from the females as they form bachelor bands that they will stick with until the pre-rut. They will begin to migrate to their favorite thermal cover for antler development, open hillsides and open forest with little or no obstacles to bump or damage delicately forming antlers. The females will begin to retreat to the birthing areas, which are often the same places that the breeding occurred, providing high visibility to approaching predators and cover, such as high grasses, lots of freshwater, and good amounts of thermal sunlight that is essential to growing fawns. Plan your scouting in conjunction with this process as well, if you want further predictability in your animals come fall and the rut.

Taking the time to explore and become objective about what is happening around you is truly a best practice for becoming a proficient observer and locator of wildlife. Monitoring weather and seeking to understand how it affects animals at all times of the year will be a key to predicting their movement and ultimately their location at any time.


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