Fire Effects on Northern Bobwhites (Colinus virginianus)

Northern bobwhites, which are colloquially referred to as bobwhite quail or quail in the Southeast, are a popular and economically important game species throughout much of their range (Burger et al. 1999) and they inhabit a variety of habitat types throughout most of the eastern US (Brennan 1999).  Preferred vegetation types range from landscapes dominated by agricultural activities (Roseberry and Klimstra 1984), arid regions of western Texas and Oklahoma (Lehman 1984), and southern pine forests (Stoddard 1931, Rosene 1969).  This wide assortment of plant assemblages share a common habitat structure of a sparse to open overstory canopy coupled with an expansive herbaceous and shrubby ground cover.  In many of these habitats, especially forested areas, fire is an integral part of maintaining plant structure and composition suitable to northern bobwhites (Stoddard 1931, Speake 1967, Rosene 1969, Burger 2001).  In the 1920’s, Herbert Stoddard began the first research on the effects of prescribed fire on aspects of the bobwhite’s life history and habitat.  This work was conducted in pine forests of southern Georgia and northern Florida and demonstrated the benefits of fire to bobwhite populations.  This initial research was summarized and published in his classic book The Bobwhite Quail: its habits, preservation, and increase (Stoddard 1931).  Despite recognition of the beneficial influence fire has on bobwhite habitat and populations in general, details of the specific demographic pathways that fire maintained habitats influence bobwhite life history are less well known.

While the timing of natural fire likely varied throughout the bobwhite’s range, longleaf pine (Pinus palustris) ecosystems (Frost 1993) were historically maintained by natural fires in the late spring and early summer months of May and June (Komarek 1964).  Recent research is indicating that timing of fire during the year, whether in the traditional period of February and March or during the natural season from May to June, can have a profound impact on habitat structure, species presence and abundance, and can influence timing of critical life history events, such as flowering (Robbins and Myers 1992).  Prior to European settlement, bobwhite habitat in the Southeastern Coastal Plain was primarily dominated by the longleaf pine ecosystem prior to European colonization (Wahlenberg 1946, Frost 1993).  Longleaf pine habitats are characterized by an understory of mostly grasses, especially wiregrass (Aristida spp.) and broomsedge (Andropogon virginianus), and legume species plus scattered shrubby species.  The midstory was absent or minimal, and the overstory was predominantly longleaf pine, with slash pine (Pinus elliottii) occasionally on wetter sites (Peet and Allard 1993).  These areas were characterized as “park like” by early explorers and this habitat structure was maintained by frequent fire during late spring and early summer (McPherson 1997, Komarek 1964, Glitzenstein et al. 1995, Frost 1998).  Natural fire during this time of year was likely caused by increased lightning activity (Komarek 1964).  Fires between April and August are termed growing season fire (Robbins and Myers 1992).  These fires coincide with the breeding season of bobwhites (late May to September; Brennan 1999), and unfortunately their impact on bobwhite demography is not well understood.  

Research concerning direct influence of prescribed fires on bobwhites is minimal, although it is highly unlikely that natural or prescribed fire kills healthy, flight-capable bobwhites.  However, if eggs are present many, if not most, are certain to be destroyed by fire, and it is probable that flightless chicks (hatch to 14 days; Brennan 1999) are susceptible to fire caused mortality.  These specific topics have received little attention, and the impacts of these losses on bobwhite populations remains unknown. 

To better understand the effects of prescribed fire on bobwhite populations, we need to examine how fire alters the birds’ habitat and how changes translate into changes in bobwhite survival, reproduction, and movement.  To date, most studies have documented changes in apparent abundance of bobwhites in response to a single prescribed fire.  Studies of this type have been conducted throughout a variety of physiographic regions and consistently demonstrate the beneficial nature of prescribed fire to bobwhites, especially as compared to control plots where fire was excluded.  Recently, some research has focused on the influence of fire on bobwhite demography, specifically survival rates and nesting biology.  Although relatively few studies have been conducted, none have shown a consistent and negative effect of prescribed fire on bobwhite survival or nest success.  Considerable work has also evaluated how important bobwhite food plants are influenced by prescribed fire, particularly leguminous species, which are an important bobwhite food source.  Additionally, researchers are beginning to realize how long-term annual fire can negatively influence age structure of pine forests on areas managed exclusively for bobwhites.  Limited work has also been done on the relationship of exotic flora and fauna to fire, which may in turn influence bobwhite populations.  Despite being the focus of research for nearly eight decades, research gaps still remain concerning the influence fire has on the life history of northern bobwhites.