From the Field

Connecting YOU with Wildlife – Pennsylvania Game Commission


Factors in Determining State Game Land Food Plots

Cost

When deciding what to plant for wildlife on state game lands, our primary motivation is getting the best bang for our (your) dollar. Budgets for lime, seed and fertilizer never seem to be enough, so, in some cases what we plant is governed by what we’ve received as donations. These donations can range from corn, wheat or oats to turnips, rape or sunflowers.

Wildlife Benefit

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Along with cost we also consider a crop’s usability by multiple species.  A typical mixture might include legumes such as birdsfoot trefoil, alfalfa and two or three types of clover to ensure viability. Some types of clover are more drought-resistant than others

Choice Legumes

 

Legumes are often selected because they grow well and quickly in Pennsylvania’s climate and soils and because virtually all species of wildlife utilize them.  These plants are eaten by most birds and mammals. Also, legumes promote large populations of insects. Young game birds require large amounts of protein, which can be obtained through a diet high in insects. Legumes provide a year-round food source and, if properly cared for, a field can last four to five years.

Winter Availability

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Brassicas (species such as turnips, kale and rape) are planted later in the year and make a great winter food source for larger animals such as deer and bear.

Typical agricultural crops such as corn, soybeans and buckwheat are rarely planted for a number of reasons. While such plantings are heavily utilized by deer, they tend to be used during a time of year when natural foods are most abundant and are completely consumed by the time wildlife needs them most, mid to late winter. Also, these plants are annuals and require replanting each spring.

Cover Crops

In almost all cases, a cover crop of either wheat (late summer, early fall) or oats (spring) is sewn with the chosen food plot mix to serve as a buffer between the time when soil is bare and the emergence/establishment of the chosen crop. These plants are also eaten by wildlife and help to prevent soil erosion. The seeds from the cover crops will eventually provide seed heads for various bird species to utilize.

Variables

As you can see, there are many variables to consider when deciding what the Game Commission food and cover crews plant in the state game land food plots. Costs to plant and maintain, crop viability, availability to wildlife during high need seasons, and usefulness to multiple species all factor in agency decisions.

By Art Hamley, Pennsylvania Game Commission Land Management Group Supervisor

Photos By Hal Korber

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Gypsy Moths

In a recent blog post, I discussed the benefits of a warm and dry period in the spring that was beneficial for the development of acorns. We received numerous comments since that posting about a different benefactor of that warm, dry spell this spring. It is causing a bit of concern.

gypsy moth caterpillar

Gypsy Moth Introduction

The gypsy moth was accidentally introduced into Massachusetts in 1869 by a French scientist trying to find a disease-resistant caterpillar to increase the output of silk. Since first being detected in Pennsylvania in Luzerne and Lackawanna counties in 1932, the gypsy moth has wreaked havoc on Pennsylvania’s forests, killing millions of oak trees along the way. The gypsy moth is now one of the most destructive insects in the eastern United States. It is one of many foliage-eating pests that cause an estimated $868 million in annual damages in the United States.

Effect on State Game Lands

State game lands suffered tremendous impacts from gypsy moths in the 1980s and 1990s. Tens of thousands of acres of oak forest experienced significant defoliation. Many of these areas had salvage harvests done to make use of the dead timber, which combined with other factors, helped to regenerate forests that were no longer dominated by our important oak species. The management of these declining oak forests is still one of the most pressing challenges facing foresters today.

Treatment

Defoliation that occurs in multiple years can often stress trees to the point where mortality can be noticed on a large scale. Therefore, pest suppression efforts for gypsy moth are an important part of active habitat management on our state game lands. In a recent outbreak in 2008-2009, state game lands suffered more than 100,000 acres of severe defoliation. Funding constraints only permitted us to spray the most important areas. In 2008, pest-suppression treatments occurred on more than 43,000 acres of state game land forests at a cost of more than $1.3 million. In 2009, the Game Commission spent another $554,000 to spray more than 22,000 acres of state game land forests. Even though we have not seen a widespread outbreak since that time, our habitat managers have been vigilant in conducting yearly suppression efforts ranging from 5,000 to 13,000 acres of state game land forests across the entire state.

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Gypsy Moth Egg Masses Photo: Bugwood.org

Outbreaks

Gypsy moth outbreaks seem to run on a 10 to 12 year cycle. We cannot afford to spray every affected acre, so we must try to anticipate where the gypsy moths will show up (based on what we have seen in the past). We then try to direct active forest management so that healthy regeneration of desired species can be established before widespread mortality makes it much harder to do so. The Game Commission also collaborates with the Department of Conservation and Natural Resources and the United States Forest Service on research projects to try to identify other ways to combat this ever present and destructive pest of Pennsylvania’s forests.

Natural Control

Spraying insecticides is not the only help we have in controlling gypsy moth populations; natural factors are also very important. Since the 1980s, the fungus Entomophaga maimaiga has had a large impact on gypsy moth populations. This fungus needs cool and wet weather to negatively impact gypsy moth populations. The caterpillar larvae can feed and may cause some defoliation, but they usually die before completing the life cycle resulting in much fewer adult insects and egg masses. However in years with warm and dry periods that coincide with leaf-out in the spring, the caterpillars can do massive and widespread damage because the fungus is not as prevalent in the forest. NPV, or nucleopolyhedrosis virus, can also help to collapse expanding gypsy moth populations.

Oak Regeneration

We lost thousands of acres of oak saw timber from numerous state game lands in the 2008-2009 outbreak, most notably in Centre County. It’s not all bad news however. Salvage operations once again allowed many of the dead trees to be used by industry to produce important forest products, especially firewood. Since the deer population was in balance in many of these areas, we have also observed very good oak regeneration (in contrast to the results of the 1980s and 1990s) and some of these young forests are now supporting booming populations of grouse, snowshoe hares, and white-tailed deer. As with most things in nature, there are always winners and losers; a warm, dry spring spell can remind us of that.

More information:

Pennsylvania DCNR – Gypsy moth 

Gypsy Moth in North America

By Dave Gustafson and Paul Lupo, Pennsylvania Game Commission Forestry Division


Who’s Their Daddy?

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Game Commission Photo: Jacob Dingel

Do only top-ranking bucks breed does?

For decades, people believed the white-tailed deer mating system was a dominance-based breeding hierarchy. In other words, most offspring were sired by a few dominant males. For white-tailed deer, this meant – or at least we presumed – the top-ranking buck (based on physical traits like age, body mass, and antler size) had breeding rights to any and all females he encountered. No questions asked.

Behavioral observations set the stage for this theory of the whitetail mating system. But what happens when we aren’t watching? Thanks to genetic technology, we now realize that we only read the first chapter on white-tailed deer breeding ecology.

Multiple Paternity in White-tailed Deer

In 2002, the next chapter was revealed. That’s when an article in the Journal of Mammalogy was published titled “Multiple Paternity in White-tailed Deer Revealed by DNA Microsatellites.” This paper documented multiple paternity in captive white-tailed deer. In litters of two or more fawns, 26 percent of them had different fathers.

This discovery raised the bigger question: does multiple paternity – and female promiscuity – occur in wild, free-ranging deer populations? The answer came two years later. In 2004, the first case of multiple paternity in free-ranging white-tailed deer was documented in Michigan (Journal of Mammalogy, “Paternity Assignment for White-tailed Deer: Mating Across Age Classes and Multiple Paternity”). Here, 22 percent of litters with two or more fawns had different fathers.

This research also showed the oldest males did not monopolize breeding; thus, shattering the belief that a few dominant males do all breeding. Since this initial finding, multiple paternity has been documented in every free-ranging white-tailed deer population that has been tested.

Twenty to twenty-five percent of all those twins out there are only that in the most basic sense of the word- two offspring produced from a single pregnancy.

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Game Commission Photo: Jacob Dingel

Interesting Fawn Data

Most does birth two fawns in the spring. Triplets have been documented but are far less common.

From past embryo counts in Pennsylvania:

Two-year-old does: 34% carried a single embryo, 64% carried twins, and 3% carried triplets

Adult does (> 3 years old): 22% carried a single embryo, 73% carried twins, and 5% carried triplets.

By: J.T. Fleegle

Wildlife Biologist, Deer & Elk Management Section

Pennsylvania Game Commission