Eastern Black Rail status assessment
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 listed as endangered in six eastern states and is a candidate for federal listing. Nearly all of what we know about the population exists in bits and pieces scattered throughout more than 100 years of literature, museum specimens and unpublished observations. The objective of this project is to identify, collect and compile all information pertaining to the breeding population along the Atlantic and Gulf coasts with the intention of developing the historical context needed to inform future conservation efforts.
The historic breeding range of the eastern black rail appears to have included coastal areas from south Texas north to the Newbury Marshes in Massachusetts and interior areas west to the eastern slope of the Appalachian Mountains. A total of 1,937 occurrence records were found within this area between 1836 and 2016. Credible evidence of occurrence was found for 21 of the 23 states including 174 counties, parishes and independent cities and 308 named properties. Based on breeding evidence and seasonality of occurrence 34 (19%) counties were classified as confirmed, 97 (56%) as probable breeding and 43 (25%) as possible breeding. Many of the named properties are well-known conservation lands including 46 (15%) national wildlife refuges, 44 (14%) state wildlife management areas, 26 (8%) state and municipal parks and many named lands managed by non-governmental conservation organizations.
A relatively soft estimate of current population size for black rails within the study area is 455 to 1,315 breeding pairs including ranges of 55 to 115 and 400 to 1,200 for the Northeast and Southeast regions respectively. More than 75% of the overall estimate is accounted for by South Carolina, Florida and Texas with the latter two having high uncertainty ratings due to extensive areas of potential habitat that have yet to be assessed. This collective estimate is approximately 40-50% lower than the estimate derived during the Southeast and Northeast black rail workshops held in 2014. The difference reflects ongoing declines, an increase in survey coverage of geographic gaps and a more thorough assessment of available information.
Black rails within northern areas have experienced a catastrophic decline including a contraction of the northern range limit from Massachusetts to New Jersey a distance of approximately 450 km. Study areas in New Jersey, Delaware, Maryland and North Carolina that were surveyed in the late 1980s and early 1990s and again over the past two years have documented a 64% decline in occupancy and an 89% decline in birds detected equating to a 9.2% annual rate of decline. Maryland has experienced a 13.8% annual rate of decline. South Carolina has experienced a 4.7% rate of decline over the same time period. No information is available to assess trends for areas south of South Carolina.
Black rails within the study area have primarily been documented within sites with tidal salt marsh as the primary habitat. Of the 308 properties with documented use, 186 (60%) were salt marshes, 49 (16%) were impoundments, 36 (12%) were freshwater wetlands, 20 (6%) were coastal prairies and 17 (6%) were grassy fields. Of the sites documented within salt marshes, 65 (35%) were along the lee side of barrier islands with the remaining in estuaries or along unprotected coastlines. Impoundments included waterfowl management units, rice fields, wetland restoration or mitigation sites, spoil deposition sites, abandoned mines and farm ponds.