Grassland birds throughout the United States have exhibited significant declines in the last three decades indicated no grassland bird species in the Upper Midwest were increasing in abundance. Continental and regional population declines are mirrored in Wisconsin with species like Henslow’s Sparrow, Grasshopper Sparrow, Eastern Meadowlark and others declining by 50 – 90% since 1970. Conservation groups, state and federal agencies within the Upper Midwest have long recognized these declines and have taken action, yet despite the value of these conservation actions, none of the grassland birds have halted their population declines or returned to population sizes of the 1970s. Within the conservation community there is growing recognition that species-specific abundance and density estimates are essential to inform the conservation and management of grassland birds. However, the amount of effort and resources required to monitor species across broad spatial extents can be extraordinary; data collection exclusively by professionals at state and regional scales is typically impracticable. This has motivated efforts to work with citizen scientists to collect the necessary data. The Breeding Bird Survey (BBS) is one such long-term, large-scale, avian dataset used by many researchers and managers to estimate population sizes across large geographic extents. For example, Partners in Flight (PIF) published The North American Landbird Conservation Plan reporting estimates for 448 species in the U.S. and Canada aimed at assessing species-specific conservation act. Although the BBS was designed to monitor regional and national population trends and not to produce population size estimates, it is the only standardized long-running dataset covering such a large geographic extent. Nevertheless, PIF has been dedicated to producing the best estimates possible. Since their first population estimates were reported in 2004, they have continued to review and update their analytical methods. Even so, PIF population size estimates are “crude first approximations” and should be used cautiously in any analysis aimed at planning. Consequently, there is a need for more robust estimates that can be used for conservation planning at state or regional scales. Our project proposes to compare PIF estimates at three scales of interest in Wisconsin; 1) statewide, 2) Wisconsin’s Bird Conservation Regions, and 3) focal grassland landscapes. We will base our population estimates from a statewide point count program initiated as part of Wisconsin’s 2nd Breeding Bird Atlas (BBA). We intend to analyze 20 species encompassing a wide range of abundances and breeding habitats, including Joint Venture focal species outlined in the UMRGL JV’s assessment of bird habitat objectives and landscape trends for WI – BCR 23 and 12 (Table 1). Furthermore, we will integrate BBA point-count data with BBS data to create a model that permits the sharing of information across space and between the two different data sources (hearafter called “shared model”) (Pacifici et al. 2017). Lastly, we will use the shared model to predict and map species densities for all focal species across our landscape classification scales in Wisconsin and scale up to predict Upper Mississippi River and Great Lakes region-wide estimates.
