Secretive Marsh Bird Densities and Habitat Associations in the Prairie Pothole Region

Abstract

After centuries of wetland modification, wetland-dependent wildlife are of high conservation concern. Particularly important are secretive marsh birds, a cryptic and understudied guild of wetland-dependent birds, many of which have experienced population declines concurrent with anthropogenic modification of wetlands. We used point-based sampling to investigate densities and habitat associations of secretive marsh birds at multiple spatial scales in the Prairie Pothole Region of North Dakota. We focused on five species for modeling. The most abundant species was Virginia Rail (Rallus limicola; 0.20 individual-ha SE = 0.04), followed by Sora (Porzana carolina; 0.13 individual-ha SE = 0.02), American Coot (Fulica americana; 0.08 individual-ha SE = 0.02), American Bittern (Botaurus lentiginosis; 0.07 individual-ha SE = 0.03), and Pied-billed Grebe (Podilymbus podiceps; 0.06 individual-ha SE = 0.01). Densities of all species were best explained by multi-scale models. Despite a few commonalities, secretive marsh birds have diverse habitat requirements and models suggest species-specific wetland complex management will likely be most effective. This information provides a baseline for species with previously unknown densities and informs conservation actions and policy for secretive marsh birds in the northern Great Plains.