Black rail inventory at Cape Lookout and Cape Hatteras national seashores

Abstract

The black rail (Laterallus jamaicensis) is the most secretive of the secretive marsh birds and one of the least understood species in North America. On the east coast, eastern black rails historically bred in tidal and freshwater marshes along the Atlantic coast from Massachusetts, south to Florida. Within the mid-Atlantic region suitable black rail habitat is concentrated in the high marsh along the upper elevational zone of salt marshes. This zone is dominated by salt meadow hay (Spartina patens), saltgrass (Distichlis spicata), and is often interspersed with shrubs such as marsh elder (Iva frutescens) or saltbush (Baccharis hamilifolia). North Carolina has been a stronghold for eastern black rails within the mid-Atlantic region, with the marsh complexes associated with the lower Pamlico sound supporting one of largest concentrations and highest densities of eastern black rails throughout their range. However, even within these marshes, eastern black rail populations have experienced declines marked by reductions in occupied sites and decline in numbers within historic strongholds. Evidenced by increasing confinement to the highest portions of the high marsh in recent years, sea-level rise and increased rates of high marsh inundation are likely a major contributing factor to declines. With the population of eastern black rails declining over 75% in the last 10-20 years, the U. S. Fish and Wildlife Service formally listed the eastern black rail as threatened under the endangered species act on 9 November 2020 (USFWS 2020). To fulfill the need for information to guide management decisions on projects at Cape Lookout and Cape Hatteras National Seashores and to aide in (potential?) future designations of critical habitat, we conducted widespread, systematic surveys for black rails and other secretive marsh birds within the parks during the breeding seasons of 2022 and 2023. A total of 1,222 surveys were conducted at 431 points over the course of 2 years. In addition to recording detections of all focal species, we recorded detections of 6 eastern black rails on North Core Banks where they were not previously known to occur. The population of black rails occupying the high marsh habitat on North Core Banks could account for 5-10% of the North Carolina black rail population and increase the known sites occupied within the state.