Axis bucks in the shade.
Many exotic big game species, such as sika, fallow, and axis deer, prefer and consume the same forbs and browse as white-tailed deer. Keeping this in mind, it’s then obvious that white-tailed deer and exotic ungulates compete for limited resources on the lands in which they live. This may not be of great concern until habitat conditions become degraded, which you never want to happen. In overpopulated areas, or during periods of stress such as drought or winter, this further increases the competition both between and within these different species in the same area — whitetail compete with whitetail, exotics with exotics, and whitetail with exotics. Everyone has to eat!
Unlike white-tailed deer, many exotics have the ability to also utilize grass when the quantity and quality of forbs and browse is low. White-tailed are browsers, not grazers, so they can’t digest grass readily — so they can’t switch. During these periods of stress, white-tailed deer are forced to survive on the remaining lower quality forbs and browse and become malnourished (lower body weights, smaller antlers, poor reproduction rates) while exotics do not suffer the same effects of malnutrition.
To add insult to injury, many species of exotics are also much more aggressive than white-tailed deer and can monopolize supplemental feeding stations, as many of you have probably witnessed. If your objective is to produce the best quality white-tailed deer possible, then competition for food resources needs to be minimal and I suggests that exotics not be stocked in areas with white-tailed deer.
If there is a real desire to have exotics for year-round hunting activity, an additional source of hunting income, or to provide a more diverse hunting experience, then I suggest stocking exotic ungulates in areas where you DO NOT want to focus on white-tailed deer. If you stock them together, remember that the carrying capacity of the land includes ALL animals! You can raise trophy deer with exotics — just not as many.
Lastly, if you are looking for an exotic ungulate that is primarily a grazer at all times and provides very minimal competition with white-tailed deer, then I recommend blackbuck antelope. They are grazers, have high reproduction, and if you are creative around a stove or grill, they are even fine to eat or make into sausage.