A Deers Eyes & Sunlight
A deer's eyes are built to function best in low light - the gray light just before sunrise and just after sunset. Deer can "see in the dark," but not quite as well as they can during gray light. However, because they lack UV filters in their eyes, deer don't see as well as we do in full sunlight.
If you watch deer activity in an unhunted environment, open fields and food plots fill up with deer as soon as the sun sets. In hunted areas, deer generally don't enter fields until after dark.
The yellowish UV filters humans have in their eyes make our full daylight vision much crisper and sharper than a deer's vision (similar to how yellow-tinted shooting glasses or scope filters make things look "crisper"). Deer do not have these filters because the filters interfere with low-light and night vision. Another reason humans have UV filters in their eyes is to protect against long-term ultraviolet radiation damage from the sun. Deer do not live long enough for this to be a problem for them.
A Deers Home Range
Deer home ranges are highly variable and are affected by a number of factors, including: habitat, herd density, geographic region, habitat diversity, etc. Plus, there is a lot of confusion concerning the difference between an "annual" home range and "seasonal" home range. A deer's annual home range (the area it covers in an entire year) can be quite large, yet it's seasonal home range (the area the deer covers during a particular season of the year) can be amazingly small.
Deer basically have a "range" just large enough to meet all of their needs. Traveling long distances is bad for survival (burns excess energy and increases exposure to predators). If they can meet all of their needs in a very small area, they will do so. That is why -as habitat managers - we work hard to create highly diverse habitat, especially when working on small managed properties. If the habitat is diverse, the deer will travel less and they will spend the majority of their time on the small property. When the habitat is highly diverse, we've seen individual deer have summer ranges of as little as 20-30 acres, simply because they didn't need to travel any further. However, in large, homogeneous habitat areas, such as thousands of acres of similar age hardwoods, deer may need to travel great distances to meet their needs.
Blue Tongue Disease
Blue tongue (BT) and Epizootic Hemorrhagic Disease (EHD) are the two forms of Hemorrhagic Disease (HD).
Both forms of HD are spread by a midge (a small biting fly). Although HD does not spread from deer to deer, high concentrations of deer are known to increase the likelihood of an outbreak (simply because there are more hosts for the midges to feed on). Weather conditions also play a part in outbreaks, with warm, wet summers contributing to outbreaks (good conditions for midge reproduction).
In TN, there are localized outbreaks of HD nearly every year. But since the state's herds are exposed to the disease on a fairly regular basis, these outbreaks rarely cause massive die-offs. Some deer will die, while others become very sick. These outbreaks usually occur in late summer, and HD victims can often be found lying dead along creeks, streams and ponds, as the fever caused by the disease drives them to water. Deer that survive HD often display cracked or deformed hooves.
Camera Census ~ How To Do It
One camera for every 160 acres is the minimum recommended camera density (on a baited census) to still produce statistically viable numbers. However, to ensure I'm getting a good census, I try to get my camera density a little tighter, say one camera for every 100 or 120 acres.
When placed over bait, the camera delay should start at 10 minutes and then be adjusted if too many pictures of the same animal appear. Of course, that will depend on how long the local deer stay at a bait station. I've seen hungry deer stay at a station for 40-50 minutes per visit. In that situation, a camera delay of at least 20 minutes is required. But if the average stay is 5-10 minutes, a 10 minute delay works perfect. The cameras should run for *at least* 10 consecutive days. Fourteen days is better. Start pre-baiting the area for 10 days in advance of the start of the census.
For locating the camera station, after dividing the area into the appropriate sized blocks (whatever the camera density is going to be), then subdivide each block in thirds both longitudinally and latitudinally. Hence, each block is subdivided into 9 sub-units (3x3). Choose the central sub-unit for locating the census site. The bait station can be anywhere within that central sub-unit. This allows some flexibility while still maintaining the appropriate spatial design.
You might find some interesting differences between pre and post-season censuses. It is commonplace for pre-season censuses to slightly favor bucks, while post-season censuses slightly favor does. For this reason - if you have the time - I highly recommend you conduct both each year, and only compare pre-season census data to other pre-season data, and like-wise for post-season comparisons.
I recommend you use the maximum exposures you can buy (generally 36). I also recommend Kodak 400 speed film for automatic cameras (most forgiving of different exposure rates). On a non-baited census (or just placing the camera along a trail) I like a longer exposure film such as 800 speed (Kodak 800 for automatic zoom cameras). The 800 speed will give you twice the "flash" distance at night as 400 will. However, with a baited camera location, most of the deer will be right in front of the camera so the 400 speed will work fine. But also make sure you don't place the camera too far from the bait. I prefer 12-15 yards away. This sounds too close until you look at the pictures.
At first, check the film every day to see how many exposures are used in a 24 hour period. Then you can adjust how often you need to recheck the camera and bait.
A couple more tips:
1) Point the camera north. You don't want the sun shining into the sensor.
2) Take some advice from a "Master Baiter" (don't you love that nickname) and spread light trails of bait radiating out from the main source - like spokes extending from a hub. Just dribble a handful of bait every 4 or 5 steps, out about 50-60 yards in several directions from the main bait. This will give a "food trail" for deer to follow to the main bait pile.
Know Your Game!
Diseases and Anomalies of Whitetailed Deer
Epizootic Hemorrhagic Diseased
Epizootic Hemorrhagic Diseased (EHD), a viral disease of white-tailed deer (WTD) spread by biting insects (midges), is commonly encountered from late summer through early winter. EHD occurs in two forms. In the acute (late summer) form, affected deer are found weak or dead with a swelled head, neck, and tongue. The lungs are normally hemorrhagic and "wet," and there may be ulceration and hemorrhage on the tongue, esophagus, and forestomachs. In the chronic (fall/winter) form, deer become thin or emaciated, with healing ulcers in the digestive tract. They usually have deformed and/or sloughing hooves.
Anthrax, caused by the spore-forming bacteria Bacillus anthracis, is a rapidly fatal septicemic disease of all hoofed animals. Other species, including humans, may also be infected. Affected animals are generally found dead, but in good body condition. There may be a bloody discharge coming from body openings (e.g. mouth, nose, anus, and genital tract), and a lack of rigor mortis. When exposed to air, the organism forms very resistant spores that may reside in the soil for decades. If you suspect anthrax, DO NOT open the carcass, and seek assistance immediately. Transmission to humans is usually through scratches and skin wounds, but inhalation and ingestion have produced rapidly fatal human infections. If you suspect that you have been exposed to anthrax, seek medical attention immediately.
Cutaneous fibromas are benign, viral-induced skin tumors that are rarely life threatening unless located near the eyes or mouth where they impede sight or foraging. The tumors are "wart-like," up to 8 inches in length, and hairless. Occasionally, they become ulcerated and infected. Their presence, unless severely contaminated, does not render the carcass unfit for consumption.
Parasitism is common in all wildlife but rarely represents a cause of mortality (death loss). However, in combination with other factors (e.g. poor habitat, crowding, malnutrition, harassment, other stresses) parasitism may contribute to poor herd health. Animal parasites are frequently separated into ectoparasites (external) and endoparasites (internal).
Ectoparasites that infest the skin of WTD include numerous species of ticks, mites (mange), and lice. These agents may cause localized or widespread irritation that may lead to secondary infections. Infestation is frequently accompanied by hair-loss, redness, and crusting of the skin and ear canals. Perhaps more important are the diseases that these parasites may spread to humans (i.e. Lyme Disease or borreliosis).
Endoparasites include numerous species of roundworms, flukes, and insect larvae (bots) that invade various body systems of WTD and are frequently encountered when field dressing carcasses.
Nasal bots (Cephanemyia spp.) are the 1-3 cm long tan or white fly larvae that may be found in the upper nasal passages of WTD. The eggs are laid in the hair surrounding the muzzle, and bots move into the nasal passage during part of their cycle. Nasal bots do not pose a health threat to deer.
Lung worms (Dictyocaulus) of WTD are similar to those of domestic cattle. Clusters and lumps of thread-like worms (up to 6 cm in length) may be found in trachea, bronchi, and, rarely, in smaller airways. Heavy infestation may lead to pneumonia and death. Generally, losses due to lung worms are associated with multiple factors and are indicative of overcrowding.
Other nematodes include the arterial worm (Eleaphora) and stomach worm (Hemonchus). These are several centimeters in length and less than 2 millimeters in diameter. Heavy infestations by these can cause disease and poor-health in the herd. Eleaphora inhabit the carotid arteries in the neck and induce facial swelling and oral feed impaction. Hemonchus lives in the abomasum ("true stomach") and may produce anemia, gastric hemorrhage, and emaciation.
The large liver fluke (Fascioloides magna) is seen in WTD and domestic cattle. They are "leaf-shaped," up to 5 cm long, and found in thick-walled spaces within the liver. Heavy infestations may lead to ill health and secondary liver scarring, but they usually do not cause major losses in WTD.
Disease and parasites are part of the natural environment and are expected to be present to some degree in all populations. The effects of these organisms may range from negligible to high levels of mortality.
Nutritional deficiencies reduce the capacity of an animal to resist infection. Significant mortality from disease or heavy parasite loads is usually an indicator that populations have exceeded the carrying capacity of the habitat and that nutritional levels are inadequate. In fact, abomasal parasites counts (APCs) are a proven method of herd health evaluation with high APC values indicating overpopulation.
Habitat management practices such as food plots, soil fertilization, controlled burning, and timber management can often improve nutritional levels. However, food plots may also facilitate the spread of disease or parasites by concentrating feeding activity into small areas. Prevention is the only practical solution for combating disease and parasite problems. Veterinary treatment of wild populations is impractical. Improving herd health by harvesting enough female animals to maintain the population at or below the carrying capacity of the habitat, combined with good habitat management practices, is the only effective option.
The term anomaly is used to describe genetic abnormalities that are present in animals before birth. Anomalies are rare in wild deer populations, since individuals with severe abnormalities seldom survive. Anomalies have little impact on deer populations and are of interest only because of their uniqueness and the curiosity they generate. Anomalies of wild deer that are occasionally observed by sportsmen fall into three general categories: (1) color, (2) skeletal, and (3) antlers.
Abnormal coloration is the most obvious observed in wild deer. This includes albinism (the absence of all pigment in the hair and skin), melanism (excessive amounts of dark pigment in the hair and skin), and piebald (unpigmented spots). Piebald animals are by far the most widespread of this group. Since the white coloration of albino or piebald deer makes these animals more visible, they are subject to higher than normal predation rates while young. Piebald deer with a large proportion of white often have shorter than normal legs and dorsal bowing of the nasal bone (Roman nose). Albinism and melanism are extremely rare.
Wild deer with serious skeletal defects are seldom observed since such animals have a poor chance of survival. Shortened legs and Roman nose were mentioned as occurring in conjunction with the piebald condition. Normal colored deer are occasionally seen with a Roman nose. Animals with shortened lower jaws also occur. Abnormalities of the teeth are not conditions that would normally be observed, but due to the large number of jawbones being removed for age determination, more hunters are seeing these conditions. Abnormalities of the teeth that have been noted are the presence of extra teeth (usually a vestigial canine tooth), a missing tooth, or a tooth turned at an abnormal angle.
Unusual antler characteristics are so frequent that there is a separate class provided for them in trophy record books. The exact cause for atypical racks is not fully known, but possible causes are sex hormone imbalances, injury or infection during the velvet stage of antler development, and inherited traits. A few causes of bucks with a third antler and of males with no antler pedicels have been recorded. Several reports of "antlered does" being killed by hunters are heard each year. Such animals usually have polished antlers, and the vast majority of these are male pseudo-hermaphrodites that have external sex organs resembling a female, but have male organs internally. The rare, antlered doe, with a normal female reproductive tract, has velvet-covered antlers.
Anomalies have little impact on deer populations. However, anomalies occur more frequently in high deer populations. At higher population levels, more fawns are born, increasing the chances of unusual traits occurring. An increased number of observations of abnormal animals in a herd should be interpreted as an indicator that the herd may have surpassed optimum population levels, especially if accompanied by declines in average weights, antler, and reproduction indices.
The above information reproduced from MSUcares.com, the web site of the Mississippi State University Extension Service
Dropping Size ~ Buck or Doe?
Some will tell you that big pellets come from a buck, while small pellets are from a doe.
However, pellet size is determined by what the deer are eating, and pellets from an individual deer can vary in size dramatically depending on the diet.
Genetics and Antlers of Whitetailed Deer
The role of genetics in antler development is one of the most misunderstood areas of deer management. Many of the public think that genetics and inbreeding are the reasons that big bucks of yesteryear are no longer common place. We do know that genetics is an extremely important component of the deer management formula. However, genetics is just one of the factors that governs antler development. Age, nutrition, disease, and injury are often more important contributors to a buck's antlers than is genetics.
To understand the role that genetics plays in antler development it is first necessary to understand the contributions other factors make to a buck's antlers. Most importantly, the animal has to have adequate nutrition. Without adequate nutrition a buck with the genetic background to become the world record white-tailed buck might be less than average. An example of the importance of nutrition was demonstrated by a nine year-old buck that was acquired for breeding in the Mississippi State deer research facility. When acquired the buck had been in a private deer facility in Missouri and had been fed a mostly corn diet the previous year. It should be noted that corn is a very poor quality food for deer except during periods of high-energy drain during cold periods of the year. It is high in carbohydrates but low in protein (about 8 percent). On the corn diet, the animal grew an 8 point rack, had a 17 inch inside spread, 18 inch long main beams, and a gross Boone and Crockett score of about 115. After being in the Mississippi State pens for one year on a normal 16% protein ration, the animal's antlers increased to 21 points, a 27.5 inch inside spread, 28 inch main beams, and a gross Boone and Crockett score of 210.
Age can also effect a buck's antlers dramatically. Whitetailed deer do not achieve maturity until they are 5 to 8 years of age. Studies at Mississippi State have demonstrated the average buck achieves only about 10 percent of his potential antler development by age 1.5 years (when he completes his first set of antlers as an 18-month-old buck). We also have been able to demonstrate that there is little relationship between the first year antlers and the antler development a buck will have when he reaches the mature age classes of 5 years or older. This means a spike-antlered buck has a good chance of becoming a trophy-quality adult buck. By the time a buck has completed his second set of antlers he still has achieved only 25-35 percent of his potential antler development. At 3 years of age (few bucks live longer than this in Mississippi because of hunting pressure), a buck still only has achieved about 50 percent of his potential antler quality. It is not until 5 years of age that most bucks approach their full antler potential, and often, antlers don't reach their maximum size until 7 or 8 years of age (for captive animals raised under ideal conditions). Probably less than 1 out of 5,000 bucks would survive to the 6-year-old age class with the hunting pressure now across most of Mississippi. It is no wonder we don't see the quality of bucks that existed "back in the good old days," when hunting pressure was very low compared to today.
Another feature that may develop with age is an often-dramatic change in the conformation of a buck's antlers. Stories abound in sporting magazines about how hunters have pursued the same buck from a young age until they developed into full maturity. It is probably the exception, however, rather than the rule that a hunter could tell he was hunting the same buck from one year to the next. In watching our captive deer develop, a high percentage will experience significant antler conformation changes by the time they reach the older age classes and bear little if any resemblance to what their antlers looked like as 1, 2, or 3 year-olds. It is also the older age class bucks that begin to develop atypical points. A buck that has a perfectly symmetrical 8 point, as a three year-old, can conceivably have 16 or more points by age 6 years. However, some bucks develop their antler conformation at a relatively young age, and it certainly is not unusual for an 8 point yearling buck to remain an 8 point when mature.
Two other factors that effect a buck's antler conformation are injury and disease. Injury to a buck's antler while they are still in the velvet will often result in asymmetrical antlers with odd points, double main beams, or other abnormal characteristics. Generally, antler injuries of this type do not result in antler abnormalities the second and following years unless they occur near the base of the growing antler or to the skull. If the injury is near the base of the antler, the injury can result in abnormal development in subsequent years as well as the present year. Injury to other parts of the skeleton can also result in abnormal antler growth during subsequent years. It is well documented that skeletal injury to a hind leg will result in the opposite antler being malformed in the next and in subsequent antler growth periods. Injury to a front leg often results in the antler on the same side of the body being malformed.
Disease also can cause antler growth to be abnormal. The bluetongue and hemorrhagic diseases often occur during late summer when antlers are growing and cause antler growth to cease at that time. Bucks to which this occurs often have blackened, pithy antler tips for that year. Disease can also permanently restrict potential antler development. Nutritional and hemorrhagic can damage the digestive tract and prevent an animal from ever obtaining its optimum body condition and antler development.
Given proper nutrition, age and no injuries or debilitating diseases, it is genetics that determine the final development of a buck's antlers! Two deer can be raised together to 7 years of age under optimum nutrition and conditions. One may become a Boone and Crockett deer while the other may only develop into a mediocre 6 or 8 point deer. In this case, the genetic makeup Mother Nature gave them would determine the antler development. We know there are some geographical areas that consistently produce better quality antlers than others. We also know that, with the exception of antler injury, it is genetics that determines whether a buck will have typical or atypical antlers. Our research has shown that a buck does not always transmit his antler qualities to his offspring. For example, a buck with very poor antler qualities may produce offspring with very good antler qualities and vice versa. This means there is very little that can be done to practically manage genetics in a wild deer population because we cannot determine which deer will pass the superior genes to its offspring. Additionally, even if we could select a "superior" buck, 50 percent of the offspring's genetic information is supplied by the doe, and there is no way to identify the superior doe! Research at Mississippi State has demonstrated doe's are equally, or more important, than bucks to determining the offspring's antler qualities. This does not mean that we will not manage genetics of the white-tailed deer in the future. In fact, it is probable that we will do so through genetic introduction. However, we first need to better understand through research, such as that being conducted by Mississippi State, what is prudent and wise to do when considering manipulation of genetics in wild populations.
Crossbreeding Michigan and Mississippi Deer, a Research Update
In 1989, the first Michigan deer made the long journey from Houghton Lake, Michigan, to Starkville, Mississippi. A year later a group of Mississippi deer went north to Michigan. We have answered some of our questions in the intervening years. First, we have found that deer moved from the northern U.S. to the southern U.S. may have a difficult time adapting. Of 5 male and 10 female Michigan deer originally transported to the Mississippi State University research facility, only 5 females survived to 1994. Six of the Michigan deer died as fawns from the viral hemorrhagic disease, and 4 deer died at 2-3 years of age from pneumonia. In the same period, none of the native Mississippi deer in the Mississippi State facility died from hemorrhagic disease and no similar cases of pneumonia were seen. This suggests that the Michigan deer lack immunities to some of the diseases common in the southern U.S.
Surprisingly, the southern deer seem to have adapted quite well to the northern U.S. Although three Mississippi deer died from incidental injuries soon after their transfer to Michigan, most adapted very well to the colder climate.
The most obvious visual difference between the two races of deer is skeletal size. On average, the Mississippi deer are considerably smaller in stature than their northern counterparts. Within the same age classes, Michigan deer outweighed the Mississippi deer by an average of 25 to 30 lbs. for does and 25 to 50 lbs. for bucks.
Although body size differences were dramatic, other less obvious differences may ultimately prove more significant to the biology of the white-tailed deer. Two events we are paying close attention to are fawning dates and the timing of antler events.
One surprise finding was that the Mississippi buck in Michigan was not able to breed Michigan does at their normal breeding time. The buck was not ready to breed the does in their normal first heat cycle. As a result, the does bred by the Mississippi buck had fawns one month later than normal.
Except for those Michigan does bred by the displaced Mississippi buck, fawning dates of Michigan does have averaged almost 7 weeks earlier than Mississippi does. However, both Mississippi and Michigan does had fawns an average of 3 weeks earlier when in Michigan than in Mississippi.
Timing of the rut can be related to the buck's physical performance. This is seen when we examine the timing of antler events. Hardening of the antlers and shedding of antler velvet averaged almost a month later for Mississippi deer than Michigan deer, whether in Mississippi or in Michigan. Similarly, the casting of antlers averaged a month later for Mississippi deer.
Interestingly, the seasonal event of molting from winter-to-summer and summer-to-winter coat has not been different between the two races of deer. However, we have seen later molting for both races of deer when in Michigan compared to Mississippi, with molts occurring almost three weeks earlier in Mississippi than in Michigan.
It is well documented that daylight length regulates the timing of molting and reproductive events of deer. The preliminary findings of this study suggest that the photoperiod differences between the two locations are causing these normal seasonal events of reproduction and molting to occur three weeks earlier or later, depending on the geographic location. However, what is surprising about our results is that reproduction appears not only to be governed by photo-period signals, but also by a genetic clock which causes the two races of deer to respond at different times to the same photoperiod signals. The test of this finding will result in how the crossbred offspring from the two races of deer respond.
Initial results of reproductive activity from crossbred offspring seem to be confirming a genetic linkage is occurring for reproductive timing. The crossbred does followed so far have had fawning dates between the two parent races.
Much research remains to be conducted in the area of genetics. The results should provide many exciting new discoveries about the importance of genetics and environment to the white-tailed deer.
What is the importance about this study to the average sportsperson? The answer relates to the practice of wildlife management in every state in the country. All states have had native wildlife introduced, or reintroduced, at some time, from other geographic locations. Some of these relocations have been harmful and some beneficial to the gene pools of resident wildlife species. It is foolhardy to think that genetics will be an unimportant component of wildlife management in the future. In fact, genetics have historically been important on a large scale. With this in mind, it is extremely important we find out how genetics effects traits important to survival, reproduction, growth, and other qualities of wildlife. What better place or species to start with than our favorite game species, the white-tailed deer! Hopefully, the results of this and other studies will allow us the opportunity to wisely manage attempts involving the genetic manipulation of our native game species.
Survival Rate and Cause of Death of Adult Bucks in Mississippi
Quality Deer Management (QDM) is being practiced on many hunting clubs and on public lands in Mississippi. Because with QDM young bucks are passed over by hunters and allowed to live to older age classes, it is important to know the survival rates of adult bucks when subject to hunting mortality. A study funded by Mississippi Department of Wildlife and Fisheries (MDWFP), participating hunting clubs, Anderson Tully Company, and Deer Hunting Magazine, has helped to address this question.
We implemented a study to find the answer to the question, "what happens if young bucks are let go by hunters?" From 1989-1994, a total of 320 deer were captured on 16 study areas. Radio transmitters were placed on 167 adult bucks. Mortality occurred for 92 of the transmitter collared animals with 72 (78 percent) dying from gunshot, 12 (13 percent) from unknown causes, 6 (7 percent) capture related, 1 (1 percent) from meningitis and 1 (1 percent) from pneumonia.
These preliminary results indicate that adult bucks in Mississippi have very low natural mortality rates. If protected from hunting mortality as yearlings, there is an extremely high probability that the same buck will live to an older age class. Thus, protecting these young bucks should not greatly reduce the hunter's bag. Instead, protecting young bucks improves the quality of the deer herd and the hunting experience.
What Has Happened to the Rut?
The two men in the coffee shop were in a dilemma. They had always scheduled a week's vacation the first part of January. For many years, that was the week the deer moved the most and hunting seemed at its best. The last couple of years, however, the deer hunting had not been the same. In earlier years, they could always count on the bucks to be chasing does at that time. It seemed things changed the year after they had agreed to follow a biologist's recommendations and start harvesting many does. Now they were not so sure they had done the right thing. They were seeing fewer deer and the hunting definitely did not seem as good as before. However, they had to admit the deer they did harvest were in better condition and all the does seemed to have two fawns.
The conversation was just about to change subjects when another man who belonged to their hunting club entered the restaurant. They had not seen their friend since before last hunting season. The conversation turned back to hunting, and they asked what sort of hunting season their friend had. They were surprised to hear that he thought the last season had been the best he ever had. He had always taken his vacation the week before Christmas. He could not remember when he had seen so much deer activity. He had killed a heavy-beamed 10 point on Christmas Eve morning as it chased a doe past his stand.
The situation just described is happening all over the South. The dates might range from October through January, but the rut is changing. To understand why, we need to examine what determines the rut.
The rut is the period when breeding occurs. It is determined by when the does enter estrus, or heat. In much of Mississippi and Alabama the rut can be as late as the first couple weeks of January. Recent research has indicated that the rut is controlled largely by genetics. In fact, deer can be found somewhere in North America breeding in every month of the year.
We know that the rut can be modified by changing the photoperiod, or hours of day-length, a deer is exposed to. This is because of a photo-sensitive gland known as the pineal gland found at the base of the brain. This gland is actually derived embryologically from a third eye. The pineal gland controls the reproductive centers of the brain and serves as a "biological clock." We believe that genetics sets this biological clock, but photoperiod regulates when the clock starts or stops.
A scientist named Richard Goss demonstrated the importance of photoperiod. Dr. Goss found that if deer were placed in controlled rooms and the number of dark versus light hours in the day were regulated, the reproductive period of deer could be changed. In fact, deer transported to the Southern Hemisphere (New Zealand or Australia) from the Northern Hemisphere will actually change their reproductive cycles by 6 months.
Despite the importance of photoperiod as a regulator of the rut, photoperiod changes do not explain the changing rut currently experienced by many hunting clubs. Annual changes can occur due to slight changes in the weather, but it does not account for the magnitude of change we see in some areas. In fact, although the timing of the rut has changed for some hunting clubs, others in the same areas have not changed. So what is causing this change?
Many clubs harvest an average of 70 percent of the antlered bucks annually. This pressure on adult bucks produces a heavy distortion of sex ratios, and we believe this results in too few bucks to breed the receptive does on their first estrous cycle. When a doe comes into estrous, or heat, she is receptive to a buck for a period of about 24 hours. If she is not bred in that period or does not become pregnant, she will not come into estrous again for another 22-28 day period.
We have seen a changing rut where hunter harvest has shifted from heavy buck and light doe harvest to heavy doe and moderate buck harvest. An early 1990's study at Mississippi State University found that hunting clubs that harvested at least as many does as bucks had average breeding dates at least 2 weeks earlier than those that did not have equal sex harvest. Some clubs that have been practicing equal-sex deer harvest for many years have actually shifted the rut as much as a month earlier.
Hunting clubs now engaged in QDM (showing restraint in harvest of yearling and 2-year old bucks and harvesting an adequate number of does) have seen many positive changes in their deer herd. Not only has it provided more venison for the table, but also the chance to harvest 3-year old and older bucks in numbers never before experienced. Because fawning is earlier, fawns develop earlier and experience higher survival and better growth rates.
With proper management, the end result is everyone wins. Hunters have an earlier rut to hunt. The deer herd and habitat are in better condition. It seems contrary to what many hunters were raised to believe; i.e. shooting as many does as bucks. However, we now know doe harvest is required if we want to maintain deer herds in their most productive state. Most deer herds in the South have increased to the point that they will seriously damage their habitat, health, and productivity unless adequate antlerless harvest is practiced. Hunters should be aware that adequate antlerless harvest will change the period of the rut. Thus, start now in planning an earlier vacation for the future!
The above information reproduced from MSUcares.com, the web site of the Mississippi State University Extension Service