Mortality of Adult Colinus virginianus L. (Northern Bobwhite) from Prescribed Fire James A. Martin1,*, William E. Palmer2, Dallas P. Grimes1, and John P. Carroll1 Abstract - Colinus virginianus (Northern Bobwhite) respond favorably to frequent disturbances in most physiographic regions of their population distribution. These disturbances maintain the vegetative composition and structure needed for survival and reproduction. Prescribed fire is an important habitat management tool if used according to proper prescriptions and objectives. However, under certain conditions, prescribed fire may have deleterious effects on populations and individuals. We describe a single observation of an individual Bobwhite killed by a prescribed fire event. To our knowledge, this is the first observation of its kind in the scientific literature. We believe this occurrence is uncommon under most conditions while conducting prescribed fires. However, managers should consider the fuel conditions, weather variables, and scale of fire before conducting prescribed fires for Bobwhite habitat enhancement. Based on this observation, other upland birds may be susceptible to direct mortality from prescribed fire events. Disturbances are essential to maintain vegetation in a composition and structure suitable for Colinus virginianus L. (Northern Bobwhite; hereafter Bobwhite) to survive and reproduce. Without disturbances, Bobwhite population growth rates become negative, and within a short-time frame (3–5 years), Bobwhites can become locally extinct (Engstrom et al. 1984). However, in areas of lower site productivity Bobwhites are well suited for late seral stages (Spears et al. 1993). Prescribed fire has been a habitat management tool (i.e., disturbance agent) for Bobwhites for almost a century (Stoddard 1931) and remains essential for sustaining Bobwhite populations throughout much of its range. Fire increases the abundance and availability of food, increases mobility through vegetation, maintains a vegetative structure conducive to escape and proper thermoregulation, and likely decreases parasite loads (Brennan et al. 1998, Cram et al. 2002). Fire behavior is very specific to the fuel being burned, weather conditions on the day of burn, time since previous burn, ignition techniques, and other variables. Bobwhite habitat managers often operate under the assumption that Bobwhites suffer no negative effects of the prescribed fire they ignite. Here we report an example of a direct mortality of an adult Bobwhite by a prescribed fire. The mortality event reported herein was observed on a private ranch in Osceola County, FL. The upland vegetation of the study area consisted of highly pyrogenic species, such as Serenoa repens Bartram (Saw Palmetto), Aristida spp. L. (Wiregrass), Andropogon spp. L. (Bluestem) and Schizachyrium spp. Nash (Creeping Bluestem), Ilex glabra Chapman (Gallberry), and Pinus palustrus Mill. (Longleaf Pine) litter. Fire frequencies on the property range from 2–3 years, with most patches burned every two years. In this instance, the patch burned had been burned 2 years previously, and this burn was conducted in late July 2008. As part of a long-term study investigating Bobwhite ecology, there were radiotagged Bobwhites interspersed throughout the study area. The necklace type radio-tags weighed approximately 6–7 g and were placed on birds weighing greater than 150 g. During the breeding season, these Bobwhites were monitored on a daily basis to assess daily survival rates and habitat use in relation to prescribed fire events. We initiated a prescribed burn of approximately 25 ha. Fuel moisture was high because of the high rainfall amounts in the weeks prior to the fire event. The burn unit was on the upwind side of a Taxodium distichum Rich. (Bald Cypress) drainage that was filled sufficiently Notes of the Southeastern Nat u ral ist, Issue 9/1, 2010 181 182 Southeastern Naturalist Notes Vol. 9, No. 1 with standing water and acted as a natural firebreak. Therefore, we ignited a head fire on the west side of the burn unit. The steady wind (11 km/hr) carried the fire swiftly towards the east boundary at a rate of approximately 26 chains/hr. Fire behavior was not extreme—fl ame height reached a maximum of 4 m. However, the high moisture levels in the fuel, high ambient temperature (35 °C), and high relative humidity created dense smoke conditions in the immediate vicinity of the leading edge of the fire. The day following the prescribed burn, we located all radio-tagged Bobwhites on the study area. We noted a mortality signal coming from the burn unit from the previous day. We used homing to locate a fire-scorched adult male Bobwhite. Evidently, this Bobwhite was overtaken by the fire or was disoriented by the extreme smoke, which resulted in inability to escape the fire. The morning of the fire, the Bobwhite had been located outside the burn unit (200 m away), indicating the Bobwhite was alive and moving around prior to the afternoon of the fire. Excluding the scorched feathers, the Bobwhite had no other signs of mortal wounds (e.g., puncture wounds from avian predator or broken vertebrae). The transmitter was scorched and slightly melted, but worked properly. There was no evidence that the Bobwhite had been tangled in the transmitter. We report only one localized event of an adult Bobwhite being killed as a result prescribed fire, but speculate that it may be a more common occurrence than realized in some situations. It is common practice in the southern US to burn large patches (>1000 ha) in a single event. Furthermore, to achieve these objectives, head-fires typically are used to speed up the process. We caution managers to consider the fuel and weather conditions and objectives of the burn before igniting such fires. Bobwhites are poor long-distance fl yers, and if forced to fl ush multiple times during hot weather conditions, they may be susceptible to perishing in a large-scale fire. We still strongly advocate the use of frequent prescribed fire as a habitat management tool, realizing that Bobwhite population growth rates are not likely affected by only a few deaths from prescribed fire. However, direct mortalities may be significant for low density and declining populations. Bobwhite populations are very sensitive to changes in adult mortality rates, especially just prior to or during the breeding season (Sandercock et al. 2008). More research needs to be conducted on fire scale and intensity in relation to Bobwhite behavior and demographics. We lack knowledge on the direct effects that fire behavior and ignition techniques have on Bobwhite individuals and populations. Researchers working on study areas managed by prescribed fire should consider the possibility that direct mortality might occur and develop methods to detect these events. In our instance, if we had not located Bobwhites daily, we could not have described the situation herein with any confidence. The carcass likely would have been scavenged with only the transmitter remaining. Acknowledgments. We thank the Ingram and Johnston families for providing a study site and funding for this research. We would also like to thank the University of Georgia, Tall Timbers Research Station, and Land Conservancy, Inc. for support. The editor and referees made considerable improvements to this manuscript. Literature Cited Brennan, L.A., R.T. Engstrom, W.E. Palmer, S.M. Herman, G.A. Hurst, L.W. Burger, and C.L. Hardy. 1998. Whither wildlife without fire? Transactions of North American Wildlife and Natural Resources Conference 63:402–414. Cram, D.S., R.E. Masters, F.S. Guthery, D.M. Engle, W.G. Montague. 2002. Northern Bobwhite population and habitat response to pine-grassland restoration. Journal of Wildlife Management 66:1031–1039. 2010 Southeastern Naturalist Notes 183 Engstrom, R.T., R.L. Crawford, and W.W. Baker. 1984. Breeding bird populations in relation to changing forest structure following fire exclusion: A 15-year study. Wilson Bulletin 96:437–450. Sandercock, B.K., W.E. Jensen, C.K. Williams, and R.D. Applegate. 2008. Demographic sensitivity of population change in the Northern Bobwhite: A life-stage simulation analysis. Journal of Wildlife Management 72:4, 970–982 Spears, G.S., F.S. Guthery, S.M. Rice, S.J. Demaso, and B. Zaiglin. 1993. Optimum seral stage for Northern Bobwhites as infl uenced by site productivity. Journal of Wildlife Management 57:805–811. Stoddard, H.L. 1931. The Bobwhite Quail: Its Habits, Preservation, and Increase. Charles Scribner’s Sons. New York, NY. 1Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30601. 2Tall Timbers Research Station and Land Conservancy, Inc, Tallahassee, FL 32312. *Corresponding author - martinj@warnell.uga.edu.