Code
CCBTR-09-10
Publication Date
2009
Abstract
The Black Rail (Laterallus jamaicensis) may be the most endangered bird along the Atlantic Coast. Over the past 10-20 years, populations in Virginia and Maryland have declined more than 75% and have become dangerously low. There has been a reduction in both the number of breeding locations and a loss of individuals from historical strongholds. Recent evidence suggests that Black Rails may only breed in a dozen or fewer places in each state along the Atlantic coast. The reasons for the dramatic decline of the Black Rail are not completely understood but may be attributed to factors such as habitat loss and degradation, predation, low reproductive rates, overwinter survival, and environmental contaminants. Until this study, the status of the Black Rail in coastal Virginia had never been systematically determined. Information on the species occurrence only existed in the form of anecdotal accounts and a small collection of unpublished historical records. These accounts generally characterize Black Rails being patchily distributed within tidal salt marshes on the eastern shore of Virginia but its overall distribution within this region was poorly known. Basic abundance and distribution information are central to the development of an effective conservation strategy. The objective of this study was to determine the status and distribution of Black Rails in Virginia using a systematic, targeted survey effort. We established a network of 328 survey points throughout coastal Virginia within marshes containing historical occurrence records, and marshes with appropriate habitat. Surveys were conducted at night during the Black Rail breeding season in 2007 and 2008. Black Rails were only detected at 12 survey points (< 4 % of total). All detections were restricted to the bayside marshes of Accomack County on the Delmarva Peninsula. No Black Rails were detected on the seaside of the Delmarva Peninsula, the western shore of the Chesapeake Bay, along the James –York-or-Nansemond rivers, or Back Bay. The location of all Black Rail detections shared 4 primary characteristics; 1) being within the high marsh zone, 2) near the upland edge, 3) within a zone of scattered Red Cedars or pines, 4) and only where the upland matrix was composed of a block of pine forest. Black Rails use the highest elevation areas of salt marshes composed primarily of a cover Salt-meadow hay (Spartina alternifolora), salt-grass (Distichilis spicata), and black needlerush (Juncus romerianus). Black Rails appear to have retracted completely from their historical distribution along the seaside of the Delmarva Peninsula. Moreover, known population strongholds at locations such as the Saxis Wildlife Management area have been dramatically reduced compared to past accounts. Black Rails are only occupying a small fraction of the available habitat. Overall populations appear to be dangerously low and may be at a risk of extirpation in the Commonwealth of Virginia. The future of this species is uncertain because Black Rails occupy habitats that are vulnerable to land-use change, in close proximity to upland nest predators, and sensitive to changes in climate and sea-level rise.
Species
Black Rail
Source
Center for Conservation Biology Technical Report Series. College of William and Mary, Williamsburg, VA.
Pages
22
Recommended Citation
Wilson, M. D., B. D. Watts, and F. M. Smith. 2009. Status and Distribution of Black Rails in Virginia. CCBTR-09-10. Center for Conservation Biology Technical Report Series. College of William and Mary, Williamsburg, VA. 22 pp.
