National Wildlife Refuge System Protocol ...

This survey protocol provides standardized methods for monitoring secretive marsh birds during the breeding season on National Wildlife Refuges across North America. The standardized survey methods for marsh birds originated from suggestions during a workshop at Patuxent Wildlife Research Center (Ribic et al. 1999), and the methods were discussed and recommended for widespread use at a subsequent workshop at Patuxent (U.S. Fish and Wildlife Service 2006). The survey methods incorporate a 5-minute passive listening period followed by a series of 1-minute segments of call broadcasts to increase detection probability of focal marsh bird species. Several approaches that allow analysts to account for imperfect detection are provided. We include suggestions and guidance on probabilistic sampling designs and data analysis techniques to meet a variety of local and regional scale management objectives. Survey timing and associated costs will vary among refuges depending on logistics and the number and location of survey points.