Secrets of the Marsh: Eastern Black Rails and Other Elusive Birds Detected Through Inventory at Cape Lookout and Cape Hatteras National Seashores  

By Summer Boulais, I&M Science Communicator

Similar to a game of hide-and-seek, researchers went on a quest for secretive little birds on the seashores of North Carolina. Concealed in the salt marshes, eastern black rails (Laterallus jamaicensis jamaicensis) move through tunnels in the grass like undercover agents. These birds are only about five inches tall, so the best chance at finding them is listening for their calls.

A salt marsh can be defined as an area of coastal grassland that is regularly flooded by seawater, as shown at Cape Lookout.

Jon Altman/ Cape Lookout Manager

Significance of Eastern Black Rails

Eastern black rails serve as valuable health indicators of the salt marshes at Cape Lookout and Cape Hatteras National Seashores (NS). They are affected by changes in coastal wetlands, so their absence can serve as a warning of disturbances to the ecosystem. Notably, the population of eastern black rails has declined more than 75% in the past 10–20 years. In 2020, the U.S. Fish and Wildlife Service listed them as Threatened under the Endangered Species Act.

Safeguarding Threats

The biggest threat to eastern black rails is rising sea levels. The birds occupy a narrow window of elevation in the upper zone of marsh habitats, so their nests and ability to reproduce are vulnerable to flooding. To understand their status in the Seashores, park staff collaborated with the National Park Service’s Inventory and Monitoring Division to survey the eastern black rail and other secretive birds.

Searching for Sounds

During the surveys, researchers listened for the black rails’ territorial and breeding calls while the birds stayed hidden in the vegetation. They determined locations of possible black rail habitat and accessed these remote spots through foot, vehicle, or kayak. The researchers then broadcasted pre-recorded calls to elicit sounds from the birds during their most active times, before sunrise and after sunset. While standing 5 meters away from the call device, surveyors recorded detections of all birds that were seen or heard.

Series of Results

Six eastern black rails were detected on the North Core Banks at Cape Lookout NS. Black rails occupying the high marsh habitat on the North Core Banks could account for 5–10% of the total population in North Carolina. The North Core is adjacent to the Cedar Island National Wildlife Refuge, allowing eastern black rails to travel between the Refuge and Seashore marsh habitats. Jon Altman, biologist at Cape Lookout NS, explained, “It’s exciting to know we have the habitat, and the birds are still out there even though they’re really secretive.” Other elusive marsh birds were detected at both Seashores, including the Virginia rail, clapper rail, seaside sparrow, marsh wren, and sedge wren.

Extensive salt marsh habitat surrounds the boardwalk on Bodie Island at Cape Hatteras.

Megan Baker/ Cape Hatteras NS Technician

Strengthening Habitats

There were no eastern black rails found at Cape Hatteras NS during the survey. This may be due to the presence of an invasive grass species– phragmites australis, also known as common reed. These reed grasses have crowded out the native wetland grasses in the eastern black rails’ preferred marsh habitat. Staff at Cape Hatteras have been working to convert marsh areas back to native grasses through aerial treatment of invasive grasses. This process involves aircrafts spraying sections of habitat to reduce invasives and allow native plants to grow. Rising water levels within the marshes at both Seashores remain a threat that staff attempt to mitigate to ensure quality habitats for the birds.

Survey Leads to Action

Results of this inventory will help inform decision-making on projects that may impact eastern black rails at the Seashores. At Cape Lookout NS, storm recovery projects aim to replace infrastructure destroyed by hurricanes. Those development plans can now proceed in areas where managers know the birds are not present. Additionally, this species inventory will be used in an updated fire management plan at Cape Lookout NS. Both Seashores are considering prescribed burns to improve habitats and reduce fire risks, while looking at how this might affect the marsh birds. In an interview, Cape Hatteras NS resource manager Michelle Tongue expressed hope that future surveys will show eastern black rails returning to Cape Hatteras based on habitat improvements implemented as a result of this survey.

Secret Success

At Cape Hatteras NS, aerial treatment seems successful in making marsh habitats more suitable for eastern black rails, as one was spotted by staff later in the year! Preserving the salt marshes is crucial for the survival of eastern black rail populations at both seashores, enabling them to carry on their top-secret missions...

This article was summarized from the source below:

Paxton BJ and Hines CH. 2024. Black rail inventory at Cape Lookout and Cape Hatteras national seashores. Science Report. NPS/SR—2024/144. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2304485