Investigating roadside bias in point-count surveys of grassland passerines

The North American Breeding Bird Survey (BBS) provides much essential information for assessing bird populations, but it is unknown how inherent assumptions of the BBS apply to grassland birds in the Northern Plains.  Understanding the effects of these assumptions on our understanding of grassland bird populations is essential given widespread declines of grassland birds as well as recent and impending petitions to list some species under the Endangered Species Act.  This project is assessing how occurrence and detection of grassland birds are influenced by roadside sampling, seasonal timing of surveys, and fine-grained habitat features such as fences and utility lines that are often associated with roads.  The study will improve inferences made from spatial models used to guide grassland bird conservation.  This study will also allow better interpretation of BBS results, improved understanding of population trends, will inform future population monitoring in the Northern Plains, and ultimately increase confidence in population data used in listing decisions.