Density and habitat associations of Henslow's Sparrows wintering in saline soil barrens in southern Arkansas

Abstract

Although the habitat requirements of breeding populations of Henslow's Sparrow (Ammodramus henslowii) have been examined, less is known about their habitat requirements and ecology during the nonbreeding season. We estimated population densities and quantified habitat associations of Henslow's Sparrows wintering in saline soil barrens in southern Arkansas. Densities of Henslow's Sparrows in the saline soil barrens were similar to those in the Longleaf Pine (Pinus palustris) Ecosystem of the southeastern United States, considered by many to be their primary wintering habitat. Henslow's Sparrows were closely associated with open areas with greater cover of Aristida spp. and globe beaksedge (Rhynchospora globularis), greater stem density at 11–20 cm above ground, more lichens, more herbaceous cover, more bare ground, greater occurrence of little bluestem (Schizacyrium scoparium) as the tallest vegetation, less moss, and less shrub cover than randomly selected sites. In contrast to the results of studies conducted in the Longleaf Pine Ecosystem, the presence of Henslow's Sparrows in our study was not correlated with the height of the tallest vegetation. Our results indicate that saline soil barrens of southern Arkansas support a high density of wintering Henslow's Sparrows and do so for longer postdisturbance periods than longleaf pine savanna. We also found that stem density near the ground was similar to that reported from longleaf pine savanna, but only about half that observed on their breeding grounds. Areas used by Henslow's Sparrows had more lichen and less moss cover, suggesting that those areas were drier than random sites within the barrens. Further research is needed to determine if large populations of Henslow's Sparrows winter in other saline soil barrens and if fire influences habitat associations and densities in the barrens.

Local-scale Habitat Associations of Grassland Birds in Southwestern Minnesota

“…2007). Holimon et al (2008) indicated that saline soil barrens in southeastern Arkansas supported Henslow's Sparrows for longer time periods post-disturbance than longleaf pine savanna habitats. Densities found on the saline barrens were similar to those found in longleaf pine savannas in the southeastern U.S. Further research is needed to assess the importance of alternative habitats for wintering Henslow's Sparrows (Cooper 2007).…”

“…Site fidelity for wintering birds was high within a winter, but not between winters (Plentovich et al 1998, Bechtoldt andStouffer 2005). Other habitats where birds have been observed throughout the wintering range include moist, grassy areas associated with power line corridors, saline soil barrens, roadsides, and unmowed fields (Pruitt 1996;Holimon et al 2008). Use of power line corridors in South Carolina was associated with depressions located on relatively exposed plateaus (Paul Champlin, Clemson University, pers.…”

Regional variation in abundance and response to fire by Henslow's Sparrows in Louisiana

“…Because Henslow's Sparrows occupy different habitats, multiple studies are needed to determine the best management for specific regions. For example, Holimon et al (2008) found that Henslow's Sparrows were positively associated with bare ground in saline soil barrens in Arkansas, but sparrows were negatively associated with patchy ground cover in longleaf pine savannas in Mississippi (Brooks 2010). Holimon et al (2008) also found that litter depth and plant height were not important in predicting the occurrence of Henslow's Sparrows, whereas Carrie et al (2002) and Bechtoldt and Stouffer (2005) found the opposite.…”

“…For example, Holimon et al (2008) found that Henslow's Sparrows were positively associated with bare ground in saline soil barrens in Arkansas, but sparrows were negatively associated with patchy ground cover in longleaf pine savannas in Mississippi (Brooks 2010). Holimon et al (2008) also found that litter depth and plant height were not important in predicting the occurrence of Henslow's Sparrows, whereas Carrie et al (2002) and Bechtoldt and Stouffer (2005) found the opposite. Bechtoldt and Stouffer (2005) and Johnson (2006) found high densities of sparrows in drier upland and mesic low‐lying habitats, whereas other investigators found birds only in bogs (Plentovich et al 1999, Brooks 2010), perhaps due to differences in upland habitats, particularly differences in fire management, among studies.…”

“…These sites had sparse herbaceous layers and understories encroached by shrubs, making them clearly unsuitable for Henslow's Sparrows. Although a quadratic or linear decrease in bird abundances over time since disturbance applies to most disturbance‐dependent grasslands in Louisiana, small edaphic prairies may remain suitable for longer periods without disturbance (Holimon et al 2008).…”