Effects of prescribed burning on swainson's warbler home‐range size and habitat use

Prescribed fire is an often-used tool for managing or manipulating wildlife habitats. However, studies on the effects of prescribed fire on conservation-priority songbirds are limited. We examined effects of low-intensity prescribed burns on vegetation structure and composition, and on habitat use of 45 radiotagged male Swainson's warblers (Limnothlypis swainsonii) during the 2008 and 2009 breeding seasons in the St. Francis National Forest in eastern Arkansas, USA. We found that home ranges in areas with extensive burning (>50% burned) were significantly larger (x¯ = 14.4 ha, SE = 3.5, n = 13) than home ranges in areas with partial burning (<50% burned; x¯ = 6.1 ha, SE = 1.3, n = 5) and unburned home ranges (x¯ = 8.5 ha, SE = 1.1, n = 27). Burning decreased understory vegetation density, leaf-litter depth, and cover, but had no effect on density of woody stems, including giant cane (Arundinaria gigantean; a native bamboo that is thought to benefit from fire). Swainson's warblers did not completely avoid burned regions of their home ranges, but individuals selected dense understory habitats in burned and unburned areas, and burning appeared to intensify selection for areas with less-variable litter depth. Low-intensity burning appeared to have minimal impacts on Swainson's warbler habitat use, but did result in increased home-range size, possibly to compensate for burn-impacted habitat patches and to enable warblers to acquire adequate food resources. Based on our findings, we suggest that high-intensity fires or frequent burning could have significant negative impacts on Swainson's warbler habitat. Also, prescribed burning alone was not sufficient to restore remnant populations of cane or a dense understory. We suggest management involving canopy openings in combination with low-intensity fire may more likely promote the development of dense understory habitat, including giant cane preferred by Swainson's warblers and other understory-dependent birds. © 2015 The Wildlife Society.