Antlerless Deer Managment

October 30, 2013 by  
Filed under Managment Tips

Quality Deer Management Association

The purpose of this article is to discuss in more detail the specifics of antlerless harvest and how to apply this information to your hunting area.

Before discussing specific aspects of antlerless harvest, it is necessary to define the term. In most states, an antlerless deer is defined as one without visible, hardened antler above the hairline during the hunting season. A few states classify spike bucks with less than a certain length of antlers as antlerless. For the purpose of this article, antlerless deer are defined as female deer of all ages and male deer less than one year old ? commonly referred to as button bucks, buck fawns, or nubbin bucks.

Why?

The obvious first question regarding antlerless harvest is why. Much has been written and researched on this topic, and many of the key reasons are listed below.

1. To reduce deer density.

In many areas, whitetail populations are at or above the carrying capacity of the land, and herd reduction or stabilization is needed. This can only be achieved through the harvest of adult does the reproductive segment of the herd. Ironically, one of the greatest obstacles to the acceptance of doe harvest by some hunters is the adage, I won’t shoot a doe because it would be like killing three deer. While on the surface this would be true assuming the doe was mature (generally 2 1/2 years old or older) and carrying twin fawns it demonstrates a lack of understanding of deer biology. Numerous studies have shown that as deer herds approach carrying capacity, reproductive success and fawn recruitment rates decline. In other words, fewer fawns are actually recruited into the pre-hunting season population than could be recruited from a smaller, but healthier herd.

2. To balance the sex ratio.

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Distorted adult sex ratios are common under traditional management programs featuring heavy buck harvests and inadequate doe harvests. Given that fawns are born in approximately equal sex ratios (if not slightly favoring males), the only way to achieve and maintain a balanced adult sex ratio is through antlerless harvests. Since bucks have higher natural mortality rates due to fighting, post-rut stress, larger home ranges, and other factors, the sex ratio will eventually slightly favor does, even in unhunted populations. With the added hunting mortality on bucks, in most cases more does than bucks must be harvested annually to maintain a balanced population. This is especially true in the early stages of many QDM programs.

3. To make room for and improve the quality of young bucks.

A goal of most QDM programs is the protection of young bucks. However, protecting a group of animals (i.e., yearling bucks) that has historically been harvested only compounds existing deer density problems unless an adequate number of antlerless deer are harvested. Most bucks protected under QDM are 1 1/2 and 2 1/2 years old, and these bucks consume nearly 1 1/2 times as much as a doe of the same age. This should be considered when calculating annual doe harvest needs.

4. To reduce the harvest pressure on young bucks and provide additional venison.

Let’s face it, deer hunters like to harvest deer, especially the first one of the season. I suspect there is something deep inside hunters that becomes satisfied when the freezer is full of venison. Consequently, by harvesting a doe early in the season, this helps relieve the pressure on both the hunter and the young bucks in the area.

5. To increase reproductive success and fawn recruitment.

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In areas where deer populations exceed the carrying capacity of the habitat, doe reproductive rates as well as fawn survival and recruitment rates suffer. In such areas, reducing herd density through antlerless harvests often results in increased herd health and, consequently, increased reproductive success. In other words, a smaller herd can produce more and healthier fawns with higher survival rates. This is why many moderate-density herds managed under QDM guidelines can sustain much higher annual antlerless harvest rates than high-density herds under traditional management.

6. To provide reproductive data.

Until someone can prove that bucks give birth to fawns, only pregnant does can provide valuable reproductive data. Such data typically includes evidence of lactation (in milk) and the presence of fetuses. Lactation data provides evidence that the doe produced one or more fawns from the previous year, while fetal information provides evidence of breeding during the year of harvest. Lactation data is especially useful on yearling does because this provides evidence they bred as fawns an indication of a healthy herd. In many parts of the whitetail’s range, late hunting seasons enable the collection of measurable fetuses from harvested does. Fetuses typically are not measurable until 40 days after conception. As such, fetuses from does bred in mid-November would not be measurable until late-December or early January.

7. To reduce dispersal of young bucks.

Research suggests that active doe harvests reduce the average home range size of young bucks (5 to18 months old) and the percent of yearling bucks that disperse from their birth area. Both result in more bucks staying closer to home instead of dispersing the typical one- to five-mile range found in most studies.

8. To reduce negative impacts of white-tailed deer.

Active antlerless harvests also provide benefits to society. Increased antlerless harvests typically result in a lower overall deer population. Less deer results in fewer deer-vehicle collisions, reduced crop and ornamental damage, and fewer overall negative interactions with humans.

When?

The best time of the hunting season to harvest antlerless deer is another important consideration. This decision, at least as it applies to adult does, should be based on the health and survival of their orphaned fawns. Typically, a whitetail fawn is weanable between 60 to 90 days after birth. Most hunting seasons are set with this in mind. As such, the majority of fawns (except those born very late) are weanable by the beginning of the hunting season.

Two studies have produced conflicting information on the survival rates of orphaned fawns. A Georgia study concluded that orphaned fawns had higher survival rates due to decreased dispersal and greater familiarity with their birth area. In contrast, a Texas study concluded that orphaned fawns had lower survival rates perhaps due to increased vulnerability to coyote predation. In addition to differences in predator abundance in these two studies, the average age of fawns at time of orphaning also differed. The fawns in the Texas study were orphaned in November, which meant they were approximately four to five months old. Fawns in the Georgia study were orphaned over an extended period of the hunting season with most being over six months of age.

Given these two studies, I would suggest harvesting antlerless early in the hunting season, except in areas with extremely high predator populations (coyotes and bobcats) or in areas with extremely late breeding periods resulting in fawns being less than 60 days old at the beginning of hunting season. In most areas, fawns will exceed 40 pounds live weight by this age.

Benefits of Early Antlerless Harvests

1. To reduce harvest of buck fawns.

One benefit of early antlerless harvest is the reduction of mistakenly harvested buck fawns. This is due to the drastic size difference between adult does and fawns early in the season. As the season progresses, fawns, especially buck fawns, begin resembling yearling does in body size and shape, making mistakes more likely. In addition, fawns are usually traveling with their mothers early in the season (versus being separated during the breeding season), which allows for a direct size comparison.

2. To increase nutrition available to other deer.

Harvesting does early also results in increased nutrition for the remaining animals. For example, since the average deer consumes around six pounds of forage per day, simply harvesting 10 does two months earlier than normal would result in the saving of 3,600 pounds of forage (10 does X 6 lbs/day X 60 days). That’s more than most one-acre food plots can produce during the same period. Importantly, removing deer early leaves forage during the critical stress period of late-winter through early spring.

3. To improve the sex ratio prior to the rut.

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While impossible in some areas due to season timing, harvesting does before the rut provides numerous benefits. First, the adult sex ratio becomes more balanced resulting in a higher number of does breeding on their first estrous (heat) cycle. This results in a healthier and more consistent fawn crop. Fewer does during the breeding season also reduces the energy expended by adult bucks. In other words, bucks have fewer does to breed and don’t have to waste precious energy chasing and breeding does that will only be harvested later.

4. To increase competition for breeding.

Under traditional management programs with high deer densities and young buck age structures, nearly all bucks actively participate in breeding. This is not to infer that young bucks have poor genetics, because genetics don’t change after conception. However, it is Mother Nature’s way for competition to exist among rival adult bucks, which results in the dominant bucks doing the majority of the breeding. Consequently, early antlerless harvests improve the adult sex ratio prior to the rut, resulting in increased competition for breeding.

5. To ensure the antlerless harvest goal is achieved.

A final, yet important, benefit of early antlerless harvests is to ensure that the antlerless harvest goal for a property is achieved. All too often when hunters wait until late in the season to begin harvesting antlerless deer, they fail to meet their harvest goal. This is due to many factors. Like bucks, does react to hunting pressure by changing their travel patterns, especially during daylight. Even where does are not harvested early in the season, they can become quite difficult to harvest late in the season. Also, it often becomes difficult to get enough hunter participation late in the season. The rut is over, the weather is lousy, the holidays are approaching, and some hunters have a freezer full of venison from deer taken earlier in the season. To make matters worse, those who are actively harvesting antlerless deer often begin to panic as the season draws near and make poor harvest decisions. This generally results in a higher than normal percentage of button bucks and/or small yearling bucks in the harvest both mistaken for does. Another concern in areas with very late seasons is the harvest of mature bucks that have already cast their antlers. This is especially common in years of poor nutrition (e.g., mast failures, food plot failures, etc.) The investment required to produce a mature buck is far too high to harvest them by mistake late in the season.

How Many?

The number of does that should be taken from a given property depends on numerous variables. It can vary from property to property and even from year to year on the same property. Some factors that influence antlerless harvest include: property size, shape and habitat quality, management goals, deer density, herd sex ratio, herd productivity, and management practices on adjacent properties. Given the complexity of this subject, it is highly recommended that you seek advice from a professional wildlife biologist familiar with your area. Within a few years, you can generally establish a baseline harvest level that can be adjusted as needed in relation to changes in habitat quality and/or seasonal conditions.

Throughout much of the whitetail’s range, deer densities range from 20 to 50 per square mile. In these areas, the harvest of one antlerless deer per 30 to 125 acres is generally required to maintain herds in a healthy condition. Within this range, most deer managers recommend a harvest rate of around one per 50 to 100 acres.

However, in highly productive areas or in the early stages of a QDM program, more aggressive harvests may be required. For example, in highly productive or highly overpopulated areas, a harvest as high as one antlerless deer per 10 acres may be required. In contrast, in low-density areas or extremely low-quality areas, a harvest of one per 150 to 200 acres, or possibly even no antlerless harvest, may be warranted. Again, seek advice from a wildlife biologist before implementing an antlerless harvest program.

Which Ones?

Which antlerless deer to harvest fawns, yearlings, or adults is another consideration. In general, I recommend the first one that offers a good harvest opportunity. This is because in many areas it is difficult to harvest enough antlerless deer, and every harvest opportunity wasted only complicates this situation. When multiple antlerless deer are present, I recommend harvesting the dominant, adult doe. One reason for harvesting adult does is that fewer buck fawns will be harvested by mistake due to the difference in body size. Another reason is because adult does are the most reproductive segment of the herd. In other words, harvesting adult does lowers the population faster than harvesting fawns and yearlings, which either don’t breed or produce fewer fawns. Fewer buck fawns in the harvest results in more bucks surviving to maturity

A dominant doe is the leader of her family group and generally the oldest. They can be identified if there is sufficient time to watch interactions among members of her group. The dominant doe generally leads her group from bedding to feeding areas and also is more likely to display aggressive behaviors toward other members of her group at feeding areas.

Hopefully, this information will help clarify the why, when, how many, and which ones of the antlerless harvest dilemma. For more information on separating antlerless deer in the field, I encourage you to obtain a copy of QDMA’s poster, How to Sex and Age Live Antlerless White-tailed Deer, available for $9.95, plus S/H, by calling 800-209-3337.

Brian Murphy is a wildlife biologist and executive director of the Quality Deer Management Association. For more information, contact the QDMA at (800) 209-3337 or www.QDMA.com

Originally posted 2009-12-23 22:36:14. Republished by Blog Post Promoter

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