Will harvesting “spike” white-tailed deer help grow bigger bucks? The foundation of many wildlife management plans are often built on one side of the other of the argument with solid reasoning either way. This age-old question among white-tailed deer hunters, ranchers, and managers, is actually a question of two parts– 1. are spike white-tailed bucks genetically inferior and, if so, 2. will culling spike bucks improve the antler size among the white-tailed deer herd. To thoroughly but briefly deconstruct the sides, we must clearly define some terminology, clarify some misnomers on the topic, and breakdown when and how the reasons ‘to cull or not to cull’ situationally apply.

Using the Texas Parks & Wildlife Department definition, a spike in the case of this writing is a white-tailed deer buck with at least one unbranched antler.¹ Our definition of an unbranched antler is a single beam or tine and does not include “cactus”, perruque, or broken antlers. We are excluding these from our criteria because cactus or perruque antlered bucks are often associated with testicular and/or testosterone related issues and broken antlers are often environmentally related (fighting, hit by a car, etc.). Deer with antlers that have not broke through the skin of the scalp are often called “nubbin” or “button” bucks are considered antlerless, not spike bucks. Culling is the act of selectively removing an animal from the population as a means of controlling or removing undesirable characteristics (bad genetics, diseases, etc.). And lastly, just so we’re clear, bigger bucks is not indicative of body size or mass… Although good body condition can be an indication of good health, our definition of bigger bucks is white tailed deer with larger, better scoring bone (antlers) on their heads.

Myths

Now to dispel a couple of myths. One common misconception about white-tailed deer spikes is this idea that “once a spike, always a spike”. This is simply not true; not that a spike couldn’t be a spike it’s whole life, but most in fact are only a spike for their first set of antlers and progressively get larger, better scoring antlers each year with age and nutrition.² A study in south Texas conducted by Stephen F. Austin State University researchers found that the average spike with 3 legal points or less at 1.5 years old will be at or above the herd average number of points and Boone and Crocket score by 3.5–5.5 years old.² Another major misconception is that all (or most) spikes are caused by poor antler genetics. The genetic aspect certainly plays a role, but in actuality, there are numerous reasons that can cause spike antlers among white-tailed deer at any stage of life. This may include injuries or infections at the antler pedicle (the base of the skull where antlers regenerate from each antler growing season) from fighting, motor vehicle collisions, or casting previous year’s antlers, opposite hind limb injuries, nutritional deficiencies, antler breakage, testicular injuries or infections, testosterone issues, harsh weather conditions during buck fawn gestation, or simply age.^1,3,4 In fact, a large portion of single spike-antlered bucks (one antler has branches and one is a spike) are caused by good ol’ nature and nurture (environmental and/or health) rather than genetics.

One study conducted in Alabama found that 62% of single spike-antlered bucks were caused by external factors like those described above.³ Furthermore, 92% of white-tailed bucks with two spike antlers are a yearling (about 1.5 years old) with their first set of antlers.¹ But, just because most double-sided spike bucks are yearlings does not mean most yearlings are spikes; only about 25%–33% of yearlings are spikes.¹

In south Texas, predation of white-tailed deer (Odocoileus virginianus) fawns and nesting game birds like wild turkeys (Maleagris gallopavo) and bobwhite quail (Colinus virginianus) is a common threat during the late winter, spring, and early summer months. During this time of year, new mothers and young are most vulnerable⁶– a fact of life that predators rely on as a primary source of nutrition for their own young survival. Fawn and nest predation includes both mammalian and avian culprits, but avian predators are more difficult to manage from a regulatory aspect. Mammalian predators of frequent concern include, but are not limited to, coyotes (Canis latrans), raccoons (Procyon lotor), bobcats (Lynx rufus), grey foxes (Urocyon cinereoargenteus), hog-nosed skunks (Conepatus leuconotus), opossums (Didelphis virginiana), badgers (Taxidea taxus), feral hogs (Sus scrofa), nine-banded armadillos (Dasypus novemcinctus), feral cats (Felis catus), and feral dogs (Canis familiaris) ^2,3,4,6. Although the effects of mammalian predator management on nesting success and survival is largely unknown, there has been evidence showing it results in significant improvements for fawn survival and recruitment³.

There are many methods for controlling predator population sizes, but snare trapping on fence-lines is a time- and cost-effective method that is often utilized for trapping mammalian predators like coyotes in southern Texas⁵. A snare is one of the oldest and most rudimentary traps, constructed from a simple wire or cable loop with a locking device that creates a cinch effect– as the animal pulls harder, the loop locks tighter and tighter around the animal’s body^1,5. Snares can, however, be set for more species-specific captures, if desired, with cable stops (allows smaller animals to escape and larger animals to avoid leg catches) and trap set design (loop size, cable-size, trap placement location, etc.)¹.

When one thinks of the old west, the mind’s eye may see cowboys and Indians in a gunfight, or maybe the transcontinental railroad cutting across the country, or a prospector panning for gold… but I think of bison. The great beasts of the plains, once millions strong in herds a mile wide that continued onward as steady as time, and nearly lost to the hands of greed and negligence. The dismal history of bison prefaced, what is often considered, one of the great conservation successes and led to bison becoming the national mammal of United States of America. But were those conservation efforts to save this iconic species actually successful– it depends on the perspective and definition of success.

North American plains bison (Bison bison) went through an extreme genetic bottleneck when the population was decimated by indiscriminate commercial hunting and disease epidemics introduced by domesticated cattle. The remaining bison were protected, and the species recovered before physical extinction, but random cross-breeding and intentional efforts to hybridize cattle and bison by ranchers and wildlife managers became rampant. Cattle ranchers were hybridizing bison and cattle to produce a “beefalo” that was heartier and more durable than cattle but with a higher quality beef than bison. When these hybrids bred back to bison, they became visibly indistinguishable from pure bison¹. As a result, wildlife managers also contributed to spread hybridized bison, often unintentionally by integrating hybridized bison into pure bison herds but occasionally intentionally to bolster bison genetics against diseases without changing the physical appearance. After generations of visually indistinguishable hybrid bison contributing to the gene pool of the population, it was thought there were only a few genetically pure herds remaining such as the Yellowstone, Custer, Wind Cave, and Castle Rock (Vermejo) Herds. Unfortunately, with the use of advanced genetic sequencing techniques, a recent study from Texas A&M University indicated that even the genetically pure herds are in fact infested with cattle genes³. This essentially means that pure North American plains bison are genetically extinct, including those bison in the Texas state bison herd at the Caprock Canyons State Park. So was the conservation effort to save bison a success? Genetically, no. Ecologically, yes, because although the remaining bison are not 100% pure, they appear as if they were pure and are still on the landscape fulfilling the ecological role. So, if we, as wildlife managers, consider the saving of bison a success, do we consider them native wildlife or exotic livestock?

At a national level, bison are considered a wildlife resource that the United States Department of the Interior actively works to restore on Native American reservation and national forest/park land⁵. At the state level, only six states (Alaska, Arizona, Montana, Utah, South Dakota, and Wyoming²) recognize bison as a game animal with regulated seasons and bag limits. In Texas, however, similar to many of the remaining 44 states, bison are considered livestock, regulated by the states’ livestock health agencies (i.e.- Texas Animal Health Commission) and propagated by private ranches for meat, fiber, hunting, or other purposes³. Bison, as “exotic livestock” in Texas, are not subject to hunting regulatory seasons, methods of take, or bag limits. The harvest of bison is legally equivalent to butchering a domestic livestock animal (cow, sheep, goat, hog, etc.), and the live sale and/or movement of bison is regulated similarly to domestic livestock, albeit with less disease surveillance (i.e.- trichomoniasis testing exemption). Despite these considerations, there is a heritage wild bison herd managed at the Caprock Canyons State Park in Briscoe County, Texas– the Official State Bison Herd of Texas.

The animals belonging to the Texas State Bison herd are descendants of the last wild Texas bison known to survive, which were rescued, adopted, and raised by Molly and Charles Goodnight in the late 1870’s. The handful of young bison were the genesis of the private Goodnight Bison Herd on the Goodnight’s JA Ranch in Armstrong County. Decades later, the bison herd was donated by the JA Ranch to the state of Texas and moved to the Caprock Canyons State Park in 1997 to become what is now the Texas State Bison Herd⁴. Occasionally these animals are rounded up for genetic culling and general health checks to keep the herd as healthy and genetically robust as possible⁴, but for the most part, the herd is managed as a wildlife resource at the park.

All this circles back to show the answer to the question, “Are bison native or exotic to Texas?”, is complicated and not-at-all straight-forward. From a cultural perspective, bison are the National Mammal of the United States and a religious symbol to many Native American cultures. From a historical perspective, the bison range included Texas and bison were never completely physically exterminated from the landscape. From a genetic perspective, pure American plains bison are likely genetically extinct. And from a regulatory perspective, bison are exotic hoof-stock in Texas.