Listening for Eastern Black Rails in North Carolina's Seashore Marshes

The eastern black rail (Laterallus jamaicensis jamaicensis) is a secretive little bird — only about five inches tall — that slips through tunnels in the grass of salt marshes. You're far more likely to hear one than see it. In North Carolina, researchers at Cape Lookout and Cape Hatteras National Seashores went looking — and listening.

A salt marsh — coastal grassland regularly flooded by seawater — at Cape Lookout. NPS/Altman

Why the rail matters

• It's a health indicator for salt marshes: it responds to changes in coastal wetlands, so its absence can warn of trouble.
• Its population has fallen more than 75% in the past 10–20 years.
• In 2020, the U.S. Fish and Wildlife Service listed it as Threatened under the Endangered Species Act.

Its biggest threat is rising seas. Black rails live in a narrow band of elevation in the upper marsh, so flooding can wipe out nests and breeding.

How they searched

Park staff worked with the NPS Inventory and Monitoring Division:

1. They mapped likely black rail habitat and reached remote spots on foot, by vehicle or by kayak.
2. In the birds' most active hours — before sunrise and after sunset — they played recorded calls to prompt replies.
3. Standing 5 meters from the speaker, they logged every bird seen or heard.

What they found

Cape Lookout biologist Jon Altman called it exciting to know the park has the habitat — and that the birds are still there, however secretive. Both seashores also turned up other elusive marsh birds: Virginia rails, clapper rails, seaside sparrows, marsh wrens and sedge wrens.

Salt marsh around the boardwalk on Bodie Island, Cape Hatteras. NPS/Baker

Why none at Hatteras

The likely culprit is an invasive grass, Phragmites australis (common reed), which has crowded out the native grasses black rails prefer. Cape Hatteras has been restoring native marsh by spraying invasive reeds from aircraft. It seems to be working: later that year, staff spotted a black rail there. Rising water in both seashores' marshes remains a threat.

Putting the survey to work

• At Cape Lookout, rebuilding infrastructure destroyed by hurricanes can now go ahead in places where managers know the birds aren't present.
• The results will feed an updated fire management plan at Cape Lookout; both seashores are weighing prescribed burns to improve habitat and cut fire risk, with an eye on marsh birds.
• Cape Hatteras resource manager Michelle Tongue hopes future surveys will show black rails returning as the habitat improves.

Sources

Based on Summer Boulais, "Secrets of the Marsh: Eastern Black Rails and Other Elusive Birds Detected Through Inventory at Cape Lookout and Cape Hatteras" (October 2024), National Park Service, summarizing B. J. Paxton and C. H. Hines, Black Rail Inventory at Cape Lookout and Cape Hatteras National Seashores (2024); a work of the United States government in the public domain.