Bird community monitoring at Wilson’s Creek National Battlefield, Missouri: Status report 2008–2020

Abstract

Breeding bird surveys were initiated on Wilson’s Creek National Monument, Missouri, in 2008 to assess temporal changes in the species composition and abundance of birds on the park and to improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 38 variable circular plots located on a systematic grid of 400 x 400-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-min sampling period were recorded. In the 13 years since initiating our breeding bird survey, birds were surveyed on as many of the 38 variable circular plots as possible each year, resulting in 444 cumulative plot visits. Surveys have yielded records for 119 different species of birds. Ninety-eight of the species recorded are classified as permanent or summer residents to the area, 18 are classified as transients in the area, and 3 as winter residents to the area. Eight breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region in which Wilson’s Creek National Battlefield is located. Of the 98 breeding species recorded, 12 species in grassland habitat and 15 in woodland habitat occurred in numbers large enough to calculate annual abundances with some degree of confidence. Trends in abundance were classified as uncertain for most species, which means that no significant increases or decreases occurred but it is not certain that trends were <5% per year. The Indigo Bunting (Passerina cyanea) population in grassland habitat was stable. The Eastern Towhee (Pipilo erythrophthalmus) and Eastern Wood-pewee (Contopus virens) populations in woodland habitat were in moderate decline. Comparing population trends on the park with regional trends for the Central Hardwoods Bird Conservation Region suggests that the bird community at Wilson’s Creek National Battlefield is faring similarly to that of the region as a whole. Stable diversity, richness, and evenness values suggest that the park’s habitat has remained consistent in its ability to meet the requirements of many of the park’s breeding bird species. Any decline in species richness could reflect habitat management practices, but it could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on Wilson’s Creek National Battlefield as management and weather and climatic conditions change is essential for park management.