Biologists play recordings in attempt to locate declining Black Rails
NORTHEASTERN N.C. — The black rail is perhaps the most imperiled bird species along the Atlantic Coast that most people have never seen. The bird’s obscurity is due, in part, to its size — about the size of a sparrow — and its secretive nature, preferring to hide among the tall grasses of freshwater and saltwater marshes during the day and foraging for insects and seeds at night.
However, wildlife biologists with the N.C. Wildlife Resources Commission aren’t seeing it either. Habitat degradation and loss, particularly of breeding sites, may have taken a toll on this smallest member of the rail family.
Over the last two years, Commission biologists have been working with the Center for Conservation Biology in Williamsburg, Virginia, to assess black rail populations in North Carolina. While the species is disappearing rapidly from sites in Virginia, North Carolina has been considered the birds’ stronghold, but even here, they are no longer present in areas they were found decades ago.
In 2014 and 2015, biologists surveyed 262 sites in North Carolina’s coastal counties to determine the presence of black rails. They selected survey locations based on the presence of habitat that black rails require and historical data that indicate black rails were detected there in the past. They also examined aerial and satellite photos along with National Wetland Inventory maps for presence of high marsh vegetation used by black rails. The high marsh is flooded on an irregular basis and is dominated by plant species such as salt-meadow hay and salt grass, mixed with black needlerush.
Because most of the sites selected for study are in remote locations, they were visited by boat and at night when black rails call most consistently and are easiest to detect.
Biologists played recordings of black rail vocalizations to get a response from live birds. This playback technique is standardized and used in other surveys for black rails in states along the Atlantic Coast.
From late April through June 2014, biologists surveyed 153 sites in Pamlico and Carteret counties, including Cedar Island National Wildlife Refuge, and this year, they surveyed 109 sites in Hyde, Dare, and Currituck counties. All rails were detected from mid-May through June.
During the 2014 surveys, biologists detected black rails at 15 of the 153 survey sites. Nine of the 15 sites were on N.C. Route 12, within the Cedar Island National Wildlife Refuge. They detected additional rails on James Creek, Jones Bay, South River and Willis Creek. In all, biologists detected 28 black rails.
Detections of black rails in 2015 surveys were disappointingly low, with biologists recording them at only five of the 109 new sites surveyed—Currituck Sound, Swanquarter National Wildlife Refuge, and three sites on the Atlantic Intracoastal Waterway.
Also in 2015, biologists with the U.S. Fish and Wildlife Service revisited 2014 survey sites in Cedar Island NWR along NC Route 12 to get a second year count of birds. They detected only four rails during the three visits in 2015, a number particularly concerning to biologists because the refuge has been known to have significant numbers of black rails in the past.
Without Intervention, Extirpation is Likely
According to the Center for Conservation Biology, black rails have been declining in the eastern United States for more than a century, experiencing a significant loss of breeding habitat as well as a sharp decline in numbers at their most critical strongholds. Recent surveys have shown an 80 percent loss of breeding sites in the Chesapeake Bay over the last 15 years.
“Without emergency management intervention, it is very possible that black rails will become extirpated in many portions of their range, including North Carolina, in our lifetime,” said Mike Wilson, senior biologist with the Center for Conservation Biology.
Sara Schweitzer, the Commission’s coastal waterbird biologist, and Mike Wilson are working together to propose experimental land management actions that may enhance habitat for the black rail. State and federal agencies could potentially manage public wetlands in ways that would provide better black rail habitat.
Despite low population numbers, the black rail is not federally listed under the Endangered Species Act, although it is listed as a species of special concern in North Carolina. Biologists recommend that the black rail be listed as a Species of Greatest Conservation Need in the next iteration of the N.C. Wildlife Action Plan.
The Commission and the Center for Conservation Biology, along with 17 other fish and wildlife agencies and conservation organizations, are members of the Eastern Black Rail Conservation and Management Working Group, which currently is working to create a Status Assessment and a Conservation Action Plan that will cover the Atlantic and Gulf coasts.
Research and management for the black rail in North Carolina are directed by the N.C. Wildlife Action Plan. The project is funded through the Nongame and Endangered Wildlife Fund and the Pittman-Robertson Fund, which is administered by the U.S. Fish and Wildlife Service. The Commission uses these funds and State Wildlife Grants to support nongame species research and management through its Wildlife Diversity Program.
Please credit Greg Lavaty.