How Fire Seasons Create Better Habitat for Bachman’s Sparrow

By Michael Warren, Dr. Mark McConnell, and Dr. Kristine Evans

Bachman’s Sparrows (Peucaea aestivalis) are an endemic songbird to the continental United States, a Red Watchlist species of conservation concern across their range, and a Species of Greatest Conservation Need in Mississippi. They historically are associated with longleaf pine forests but also inhabit open pine forests across their range. They have strict habitat requirements that require quality, herbaceous, understory vegetation maintained by frequent prescribed fire. Much of their existing habitat suffers from hardwood encroachment in part because of dormant-season prescribed fires that have shifted open pine vegetation communities from their historic composition.

Research shows that growing-season prescribed fire can provide beneficial vegetation conditions, such as diverse, herbaceous understory for Bachman’s Sparrows compared to dormant-season fires. However, evidence of this effect is limited and has yet to be investigated with experimental manipulation.

Course of Action

We designed a field experiment to evaluate the impacts of seasonal fire on Bachman’s Sparrow populations and evaluate vegetation response. We conducted this study on Marion County Wildlife Management Area (WMA). Mississippi State University researchers and Mississippi Department of Wildlife, Fisheries, an Parks’ personnel cooperated to develop and implement a prescribed fire plan that equally distributed dormant-season (January-March) and growing-season (May-August) burning across the WMA in 2021.

Research Objectives

We conducted breeding (spring and summer) and wintering bird surveys using a combination of traditional methods, such as listening for songs and visual observations across fire treatments to estimate population occupancy rates and density of Bachman’s Sparrows. We also conducted targeted mist-netting to apply leg bands to Bachman’s Sparrows. Unique combinations of colored bands were applied to captured birds to allow identification of individual birds. This information was used to quantify known bird movements and habitat use in relation to burn timing. Lastly, we collected vegetation measurements to quantify changes in proportions of hardwood encroachment, forbs, grasses, understory biomass, bare ground, and invasive plant species. These vegetation data were collected because of their relationship to Bachman’s Sparrow habitat quality.