Jason R. Bolenbaugh | Geology Reports

USGS2012

Population status and habitat associations of the King Rail in the midwestern United States

The migratory population of the King Rail ( Rallus elegans ) has declined dramatically during the past 50 years, emphasizing the need to document the distribution and status of this species to help guide conservation efforts. In an effort to guide King Rail breeding habitat protection and restoration, a landscape suitability index (LSI) model was developed for the Upper Mississippi River and Great Lakes Region Joint Venture (JV). To validate this model, 264 sites were surveyed across the JV region in 2008 and 2009 using the National Marshbird Monitoring protocol. Two other similarly collected data sets from Wisconsin (250 sites) and Ohio (259 sites) as well as data from the Cornell Laboratory of Ornithology's eBird database were added to our data set. Sampling effort was not uniform across the study area. King Rails were detected at 29 sites with the greatest concentration in southeastern Wisconsin and northeastern Illinois. Too few detections were made to validate the LSI model. King Rail detection sites tended to have microtopographic heterogeneity, more emergent herbaceous wetland vegetation and less woody vegetation. The migrant population of the King Rail is rare and warrants additional conservation efforts to achieve stated conservation population targets.

Illinois, Indiana, Iowa, Kansas, Michigan, Minneso↗

USGS2011

Secretive marsh aird species co-eccurrences and habitat associations across the midwest, USA

Because secretive marsh birds are difficult to detect, population status and habitat use for these birds are not well known. We conducted repeated surveys for secretive marsh birds across 264 sites in the Upper Mississippi River and Great Lakes Joint Venture region to estimate abundance, occupancy, and detection probabilities during the 2008 and 2009 breeding seasons. We identified species groups based on observed species co-occurrences. Two species, least bittern Ixobrychus exilis and American bittern Botaurus lentiginosus , co-occurred with other species less often than expected by chance, and two species groups, rails (Virginia rail Rallus limicola and sora Porzana carolina ) and open-water birds (pied-billed grebe Podilymbus podiceps , common moorhen Gallinula chloropus , and American coot Fulica americana ; coots were only surveyed in 2009), co-occurred more often than expected by chance. These groupings were consistent between years. We then estimated the relation of these species and groups to landscape and local site characteristics by using zero-inflated abundance models that accounted for incomplete detection. At the landscape level (5-km radius), the amount of emergent herbaceous wetland was positively associated with least bittern occupancy, whereas the amount of woody wetland was negatively associated with least bittern, rail, and open-water bird occupancy. At the local level, habitat variables that were associated with abundance were not consistent among groups or between years, with the exception that both least bitterns and open-water birds had a strong positive association between abundance and water-vegetation interspersion. Land managers interested in marsh bird management or conservation may want to consider focusing efforts on landscapes with high amounts of emergent herbaceous wetland and low amounts of woody wetland, and managing for high amounts of water-vegetation interspersion within the wetland.

Journal of Fish and Wildlife Management↗