Habitat-based distribution of breeding landbirds at Custer State Park in the Black Hills of South Dakota

In recent years, biologists have noticed a significant decline in the abundance of many migrant bird species nationwide. This change in abundance has been correlated to the decline of existing habitat or quality of habitat needed throughout the year. Although the most precipitous drop has occurred in grassland songbirds, there are limited studies on these non-game species. The Black Hills are located in the central United States, where both western and eastern bird species reside in summer. Custer State Park (CSP) is located in the southeastern Black Hills of South Dakota; its two major habitat types are pine-dominated coniferous forest and mixed grass prairie. The objectives of this study were to (1) construct a complete list of landbird species breeding within CSP, (2) identify bird species of management concern, (3) document breeding bird species' abundance and relationship to CSP habitat, and (4) relate this data to 2004-2006 Rocky Mountain Bird Observatory's northern Black Hills data. Preliminary surveys were conducted during the 2004 summer in all habitats. Point transect surveys were conducted during the 2005 summer focusing on comparison of three grassland types (native mixed grass prairie, post-burn grassland and prairie dog towns) and during the summer of 2006 focusing on coniferous forests and aquatic environments. All breeding songbirds were surveyed by foot from mid-May to late July and were stratified by major habitat types according to previously classified Aerial Stereo Photography analysis by CSP BOR map. Surveys of nocturnal breeders were conducted by vehicle during the winters starting mid-February of 2005 and 2006. Species density estimates were calculated using Program Distance and detailed habitat analysis measurements were analyzed using canonical correspondence analysis (CCA) stepwise comparison. I compared this data qualitatively with that of the northern Black Hills of South Dakota to provide baseline information to biologists for future management decisions. Confirmed breeding by 117 species of birds was documented in CSP during the 2004, 2005, and 2006 survey seasons. Six species were found in equal densities in all habitats, and thirty-two species showed a breeding habitat preference in the park, while twenty-two species were found using all of the major habitat types. Fire has had a profound impact on rejuvenation of forests and grasslands, and the movements of bird species (especially on Lewis' and red-headed woodpeckers) in and out of landscapes. I recommend CSP continue the present controlled burn regimes, natural control, and adaptive management in those areas. Riverine, marsh, aspen/birch woodlands and shrublands were found to increase species richness in the park, with greater than expected bird species counts based on percentage of land area represented in CSP. I recommend CSP continue study of aspen exclosures and controlled grazing of bison and elk. Several species of management concern, including red-headed woodpecker and McGillavry's warbler, used deciduous and riverine resources during summer months. I recommend CSP conduct furthur research on nest-success of low density species of management concern.