Assessment of black rail status in North Carolina, Interim report: Spring 2017
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. The eastern black rail (L. j. jamaicensis) is one of two subspecies that occur in North America. The form is listed as endangered in six states along the Atlantic Coast and is a candidate for federal listing. Black rails require dense vegetation for cover during all stages of their life cycle. They require wetlands with minimal water coverage during the breeding season. Historic population size was likely in the tens of thousands (25,000 to 100,000; Wetlands International) but is now believed to be in the low thousands to hundreds. Eastern black rails breed within three geographic areas within North America including the Atlantic Coast, the Gulf Coast and the Midwest. The Atlantic Coast has generally been considered to support the largest breeding population throughout the range with pairs mostly confined to the highest elevations within tidal salt marshes. Breeding range along the Atlantic Coast has contracted south more than 450 kilometers and the population is estimated to be declining by 9% annually. The primary driver of declines over the past three decades is believed to be sea-level rise and associated tidal inundation during the nesting season. North Carolina has long been recognized as a stronghold for black rails along the Atlantic Coast. The historic record of black rails in North Carolina is long and unusual being concentrated in the Piedmont and mountains in the late 1800s and early 1900s and along the outer coast over the past 40 years. Black rails appear to have thrived in the post-civil war agricultural setting but were lost along with this farming culture. Black rails have been recorded from 16 counties and breeding has been confirmed within five counties. The marsh complex in lower Pamlico Sound including Cedar Island and Piney Island has the distinction of supporting one of the largest concentrations and highest densities of black rails throughout their range. The black rail population in North Carolina appears to have declined dramatically since the 1970s. The number of calling birds within accessible parts of Cedar Island has declined from 80 to below 10. Birds have been lost from some historic sites and declined in others. Prior to 2014 no systematic surveys to assess the status and distribution in North Carolina had been conducted. During the 2015 and 2015 breeding seasons, a total of 262 points were surveyed for the presence of black rails within the outer Coastal Plain. Rails were detected within 20 (7.6%) including an estimated 22 individuals.
