Although a large componenet of turkey management is habitat management, proper harvest is critical. In fact, properly managing the hunting of any game population is essential, not only from threat of over-harvest, but also from under-harvest. Because turkey populations can be difficult to estimate, many state agencies use harvest data and other surveys as indices of population size and trends. Based on these data, managers can estimate average population sizes. There are some problems with using harvest numbers as an index of abundance for management, but in general harvest data shows population trends over time.
Turkey numbers, like any wildlife population, rise and decline over time because of environmental cycles. There are several reasons for increases and declines. Turkey populations can boom and fill available habitats if habitat is sufficient. After a peak, populations usually contract and settle to lower, but relatively stable levels in balance with local environmental conditions. Even with that said, there is still much year-to-year variation in turkey numbers due to annual variation in precipiation and natural food production.
Declines in turkey numbers may be more pronounced in some local areas. Reasons for this include cold wet spring weather, tough winters, and changes in habitat quantity and quality. In areas where open habitats such as agricultural fields, hayfields, old fields, thickets, and young forests have been lost due to development and vegetative succession, there are fewer turkeys. In areas with a larger proportion of “big woods” turkeys will persist, but at lower densities than areas with a mix of mature timber, early successional habitats, and agriculture.
Predation can play a role in limiting turkey populations, but it is more likely that the problem is poor habitat quality that makes birds, their nests, and broods more vulnerable to predation. Turkeys have evolved behaviors and reproductive strategies to cope with turkey predators, but in highly fragmented landscapes predators may be more efficient in finding turkeys and their nests. This is particularly true for nest predators such as raccoons, skunks, and opossums. In areas with poor brood habitat quality, such as low stem densities or poor overhead cover, turkeys and poults may be more vulnerable to avian predators such as hawks and owls. In these cases, habitat management is critical for long term turkey management and viable turkey hunting. Larger predators, such as coyotes, may impact turkeys or other game birds on a small scale, but it is unclear whether they can affect turkey populations in large regions.
Hunter participation during the spring and fall turkey hunting seasons can also impact turkey populations. Many states have seen declining turkey hunters.This could be due to poor recruitment of new hunters, a lack of interest in fall hunting by existing hunters, or a preference for other types of hunting, such as hunting white-tailed deer.