Effects of drought challenge hunters

By David Hart

 Blame it on bad luck, God’s will, or just a string of unfortunate weather patterns, but much of the United States has been ravaged by a prolonged period of drought. Reservoirs are drying up, crops refuse to grow and deer hunters are wondering what it all means.

One obvious impact of a long, hot, dry spell is the noticeable effects on food plots. Getting one started when there’s little rain is difficult enough; keeping it green is perhaps just as difficult. Plenty of hunters who have invested time and money in food plots have been defeated by a long dry spell that has withered crops, natural vegetation and food plots.

“The most important thing you can do is to make sure you give your food plots the right nutrients to begin with," says Whitetail Institute vice-president Steve Scott. "Healthy plants will survive the stress of a drought much better than plants that don’t have the proper fertilizer and pH level in the soil. It’s also important to match your seed choice with the soil type. Imperial Clover will grow much better during dry years in heavy bottomland soil than it will in well-drained soil on a hilltop or slope. Alfa-Rack tends to do better in drier soils.”

To meet the challenges of a weather pattern that seem to be the norm rather than the exception, the Whitetail Institute developed a new blend that includes a variety of plants capable of withstanding low levels of moisture. Extreme, a mix of extremely hardy plants, can prosper with as little as 15 inches of rain per year. Compare that to a 30-inch annual rainfall requirement to grow a healthy stand of other perennial crops, and it’s obvious that Extreme lives up to its name.

Scott says hunters who want to help deer during periods of sparse rainfall would be better off sticking with a few proven plants. “I would lean toward a higher percentage of food plot acres being planted in annuals if I were in a region that was subject to drought, but you need at least some moisture to get the seed going and the seedling needs moisture to get a healthy start,” Scott says. “If it rains once and then doesn’t rain for three months, there isn’t much you can plant that will survive. Even if it does, there’s a good chance it won’t be very attractive to deer.”

Scott also says it’s a bad idea to practice any kind of maintenance on a food plot during extreme weather conditions. Dry plants are stressed plants, and mowing or spraying can be detrimental or even deadly to food plots.

“Most plants go dormant during dry periods, so spraying may just be a waste of money and mowing can end up killing the plants you are trying to save,” he explains.

Fortunately, water — or specifically, the lack of water — is rarely a limiting factor for whitetail survival in their traditional range. There is always a pond, a creek or some man-made water source within reach. Even if there isn’t, whitetails can often find water in the most unlikely sources. David Hewitt, a research scientist at the Caesar Kleberg Wildlife Research Center in Kingsville, Texas, says whitetails in southern Texas have been known to consume large quantities of prickly pear cactus, a succulent plant common throughout the region. He said the weight of prickly pear is comprised of up to 90 percent water, and in dry times, cactus can make up as much of half of a deer’s diet. However, it’s not very high in protein and is only moderate in nutrition, he says.

Although individuals can survive dry weather, periods of drought can have a significant impact on an entire deer herd according to Hewitt. The research center is part of the Texas A&M University’s Kingsville campus and is in a region known for major shifts in weather patterns. Like much of the country, southern Texas has been ravaged by a prolonged drought.

“The biggest impact of a drought is in fawn recruitment," he says. "Without sufficient rainfall in spring and early summer, fawn survival rates can fall to as low as four or five fawns per 100 does. The obvious impact is that you’ll have fewer mature deer in the following years. On the other hand, we’ve seen fawn ratios as high as 80 per 100 does during wet springs and early summers.”

The primary reason for low fawn recruitment is the general decrease in the nutrition of the forage. Less moisture means plants grow slower or not at all and therefore produce less nutrition. Hewitt says a drought that persists into fall also translates into unhealthy does, which can mean lower birth rates. Does don’t breed or don’t carry a fetus to term in drier winters.

If they give birth in a dry spring or early summer, does are often in poor condition and produce less milk. As a result, fawns automatically have a lower chance of survival. That, combined with poor forage quality when fawns are weaned, can mean certain death. As Hewitt notes, however, wet years can mean a boom in whitetails.

“There is some speculation that in wetter years, there is more cover, so newborn fawns are less prone to predation,” he says. “It makes sense, but I don’t know of any studies that have looked at that directly. I would say that the biggest benefit of significant rainfall is in the forage quality.”

Bucks are also stressed by the decrease in nutrition forage provides during a dry spring and summer. Conventional wisdom would suggest that antler growth is stunted during a spring/summer drought because generally, antler growth is secondary to a whitetail’s survival. A buck will first put on body mass before it puts energy into growing antler mass. Hewitt recalls one study that examined the correlation between the number of whitetails entered into Boone & Crockett Club’s record book with weather patterns and found a direct link to a decrease in antler size to periods of dry weather. He also noted another study conducted in Texas that found a similar connection.

“The researchers found about a 15-point (Boone & Crockett score) difference between dry springs and wet springs” he said.

A study of red deer in southeastern Spain also found a direct correlation between annual rainfall and antler size. According to the study’s authors, “The lowest quality animals were obtained during the hunting season from October 1995 to February 1996, which coincided with the end of an extended period of drought. The best trophies were harvested during the 1996 to 1997 season, the period of highest rainfall during the study. Thus environmental conditions can have a major influence on antler size.”

Two years ago, Alabama experienced its worst drought on record, and the next year was significantly dry. Keith Guyse, the Alabama Department of Conservation and Natural Resources, Chief Deer Biologist said despite the severe conditions, there was no noticeable difference in deer body weights or antler size based on the data he gathered from hunt clubs and other cooperators. Guyse notes that his observations aren’t scientific and aren’t necessarily a good indication of how dry weather affects whitetails. However, he said he did not hear of any concern from the state’s hunters about the state’s deer herd during the severe drought.

Even if there was a noticeable difference in body weights, antler size or the number of fawns during or directly after extended periods of dry weather, there isn’t much hunters can do about it, Hewitt concludes. Whatever the reason, dry weather comes and goes and whitetails and the hunters who pursue them just have to play the hand they are dealt.