Why Predator Control Matters for Deer Populations
June 03, 2016
It's almost fawning season throughout most of the whitetails' range. Many hunters don't get as excited as I do about fawning season, but it is the key to hunts years from now.
For example, my goals for the 2013 season include tagging a 4-year-old buck. My odds of success are strongly influenced by the number of male fawns that survived during spring of 2009. Bucks that will be 4 years old during 2013 were 3 years old during 2012, 2 years old during 2011, 1 year old during 2010 and were born during 2009.
When I was in graduate school during the late 80s and early 90s, I never heard a lecture about predator control being a technique to improve fawn survival. During that time, coyotes were either nonexistent in most eastern states, or a novelty. I remember a fellow grad student who was using trail cameras (primitive devices compared to current models) to study turkeys using food plots in the mountains of North Carolina. He got a picture of a coyote and it was BIG news! I believe he only got one picture of a coyote during two years of monitoring food plots with trail cameras.
There was no coyote season in North Carolina when I was in grad school. However, coyotes are now so common throughout North Carolina that the state just changed its regulations to allow night hunting.
Similar increases in predator abundance have occurred across the nation in recent years. Several states that totally protected bears, wolves, mountain lions, bobcats, and yes, coyotes, 10-20 years ago now have hunting seasons for those species. For example, Arkansas has a very popular black bear season, and Missouri is currently determining its population of bears to prepare to have a season.
Interestingly, predator populations have expanded even as acres of available habitat decreased significantly. It doesn't take a scientist to figure out that more predators on less land likely results in more interactions between predators and prey. As a result, researchers have become quite interested in studying the impacts of predators on whitetail populations.
Benefits of Predator Control
I was involved with one such project where Cory VanGilder, a University of Georgia grad student, monitored fawn survival on approximately 2,000 acres in northeast Alabama. In short, a trapper removed 22 coyotes and 10 bobcats from the property between February and July of 2007.
Scent stations, scat surveys and other methods were used to monitor predator abundance, and it was determined the number of coyotes and bobcats decreased significantly during the fawning season following trapping (fawns are born later in that area than throughout most of the whitetails' range).
Hunters reported a 217 percent increase in fawn observations compared to the season before predators were reduced on that property. A trail-camera survey (the most reliable technique to estimate the number of deer in most habitat types) showed a 193 percent increase in fawns surviving to February compared to the February before predator reduction. Other research projects in other states have showed similar increases in fawn survival for whitetails, antelope and even waterfowl.
The Stress Factor
What's not as well studied is the stress caused on surviving deer by overabundant predator populations. Fortunately, some researchers did intensively study the health and behavior of elk when wolves were first released into Yellowstone and compared their health and vigilance (level of awareness) to elk in a portion of the park that was still free of wolves.
Briefly, the elk in Yellowstone were very healthy just before wolves were released. The massive Yellowstone fires had opened up the forest canopy and resulted in huge amounts of quality browse being produced. Simply stated, there was more quality forage in Yellowstone than had been present in decades.
Despite that, cow elk (and bison) where the wolves were released quickly began to lose weight and show other signs of stress. This was because the elk changed from spending about 10 percent of their time being vigilant to spending 45 percent of their time being vigilant. Apparently, they were scared to put their heads down and eat!
Don't let anyone mislead you. Predators kill fawns (and some adult deer), and can certainly cause surviving deer to have a much-reduced level of health. In addition, abundant predator populations can cause deer to be so alert they are extremely tough to observe.