Wild turkeys and prescribed fire in the Southern Piney Woods

Compared to any other method of habitat management and manipulation for wild turkeys in the Southern Piney Woods, prescribed fire is by far the best, cheapest and most efficient. It is also the oldest, as humans have used fire to modify habitat almost as long as we have existed. Biologists, foresters and land managers have recognized the utility of prescribed fire for wild turkey habitat management for nearly a century (Stoddard 1935). However, the use of prescribed fire is not without controversy, even among land managers and turkey hunters. Major concerns include the timing of fire — especially during the nesting season — and scale and frequency of fire.

BENEFITS

Land managers have long recognized the benefits of prescribed fire for wild turkeys. Stoddard (1963) said that “common sense control with fire of ground and understory cover” was in use by 1924 in numerous hunting preserves in southwest Georgia, and in coastal South Carolina to a lesser extent. Both of these areas retained wild turkeys even through the lowest points of regional populations, and both later served as reservoirs for restoration efforts. Stoddard also recognized the increased growth of forage plant species and the proliferation of insects in the years following controlled burns. He noted differences in plant communities resulting from varied return intervals as well.

G.A. Hurst (1981) noted that wild turkeys in pine forests benefit from the herbaceous growth and resulting insect abundance that follow prescribed fire. These increases are directly beneficial to wild turkeys, since insects, soft mast and vegetation make up most of their spring diet (Hurst 1992). 

Preference by wild turkey hens for nesting in recently burned areas (less than three years) is well-documented (Sisson et al. 1990, Still and Baumann 1990, Palmer and Hurst 1998, Martin et al. 2012, Little et al. 2014, Kilburg et al. 2014, Yeldell et al. 2017). The assumption is that these recently burned areas provide cover, forage and visibility. Wild turkey broods also use burned areas, with a preference for annually burned pine stands (Sisson et al. 1991).

An interesting benefit of prescribed fire for turkeys is the possible reduction of predation on wild turkey nests due to prescribed fire. Jones et al. (2004) wrote that southwest Georgia has shown that raccoons (widely implicated as turkey nest predators) used burned areas considerably less than expected.  This was especially true for areas burned after the previous growing season. Chamberlain et al. (2003) noted that short-rotation prescribed fire in pine-dominated landscapes apparently decreased habitat quality for raccoons, and he speculated that predation on ground-nesting birds may be lessened in these areas.

DORMANT SEASON

Dormant season prescribed fire has been a long-standing tradition in the southeast, and many land managers and turkey hunters have become so accustomed to winter and early spring burning that they view anything else with suspicion and alarm. However, natural fires in the southeast have historically been associated with lightning from summer thunderstorms (Komarek 1964, Cox and Widener 2006).  Much of the original fire-adapted groundcover was lost when farmers converted old growth forests to agriculture before the Civil War. As some of these fields were exhausted and abandoned, old-field succession occurred with a very different suite of species, which only burned well when they dried out in the winter. When this was combined with the fear of disturbing ground-nesting birds like bobwhite quail and wild turkeys, dormant-season fire emerged as seemingly the most efficient and prudent thing to do (Cox and Widener 2006). 

On U.S. Forest Service land in Mississippi in which the pine stands were burned during February and March (dormant season), Palmer and Hurst (1998) radio monitored 119 wild turkey hens during the preincubation period. Extensive monitoring of 13 hens in 1989 revealed that they used areas burned in the previous year more often than stands two to five years of age.  

Areas used by hens had lower groundcover, less woody vegetation and longer sighting distances. The authors noted that while the dormant season burns decreased woody cover and improved sighting distances, rapid growth of top-killed hardwoods occurred within two years, with a corresponding decline in wild turkey hen use in the preincubation period. Researchers noted the same preferences for nesting hens on a southwest Georgia study area burned from December through early May (Sisson et al. 1990). In this study, most nests were in areas that were one to two years post burn. Interestingly, no turkeys were located on winter-burned areas showing fresh green-up in January and February.

As in the aforementioned Mississippi study, the Georgia site exhibited rapid regrowth of dense groundcover following dormant season prescribed fire. This was particularly true for hardwood sprouts with well-developed root systems. Most unburned areas appeared too thick for turkey travel after one growing season, and were definitely too thick after two.
 

GROWING SEASON/LIGHTNING SEASON

Sisson and Speake (1994), in response to increased interest in growing-season fire and ongoing concerns about the effects on ground-nesting birds, evaluated the effects of growing-season fire on wild turkey brood habitat. Their study area in southwest Georgia was located in pine woodlands burned in late winter of the previous year. The radio-monitored hens on the study site showed high preference for nearby old fields and grazed woodlands, with no brood locations recorded in any of the spring burn plots. 

Pittman (2014), on the Ozark-St. Francis National Forest in Arkansas, investigated the effects of large-scale growing season burns and oak savanna restoration on wild turkey hens. Managers used prescribed fire and forest stand thinning in an effort to reproduce historical oak savanna habitat. In this project, GPS-monitored hens selected nest sites with high visual concealment, high percent slope and woody ground cover. The study found no clear relationship between early growing-season prescribed fire and nest selection, but the time between fires was an important factor in nest success. More time equals more vegetative cover and better nest concealment, until vegetation becomes so thick that hens will no longer use the area.

Little et al. (2014) examined the reproductive ecology of wild turkeys in south Georgia areas managed for longleaf pine restoration primarily by frequent prescribed fire. Prescribed fires on these areas were a mix of dormant- and growing-season burns, with the burning season stretching from January through July. Fire size was small, averaging only about 14 to 21 hectares, with a fire return interval of one to three years. Seventy-nine nests from 45 individual hens were monitored and 33 (42.3 percent) hatched. Most of the rest were lost to predation or observer-induced abandonment. 

Exposure to growing-season fire caused the loss of three nests (6.7 percent). Thirty-seven percent of the hens re-nested after nest loss and, of these, 43 percent hatched. Based on these results, the authors concluded that longleaf pine savanna management using frequent prescribed fire had minimal impact on wild turkey production.

Kilburg et al. (2014) also concluded that growing-season burns had minimal direct effect on turkey nest survival. This research took place on Fort Bragg Military Reservation in North Carolina. The authors calculated that about 6 percent of 30 monitored nests were exposed to fire and, of these, only one (3.3 percent) failed as a direct result of the burning. Predation was the primary cause of overall nest failure.

Komarek (1964), in recognizing the prominence of lightning-caused fire in shaping plant and animal communities, went so far as to say that “plant and animal communities have evolved largely as the effect of summer fires.”

Prescribed fire has been and will need to continue to play an instrumental role in wild turkey management and habitat management across the Southern Piney Woods. Not only will it be a valued tool, it will continue to be a controversial topic even with the historical and ongoing research conducted. These summaries provide a glimpse into the past research, providing solid information for future discussion while identifying the need for additional research.

— Mark Hatfield, NWTF director of conservation

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