Light-footed Clapper Rail (Rallus longirostris levipes)

State and Federal endangered species (35 FR 16047)

Light-footed Clapper Rail By Peter Knapp

The light-footed clapper rail is a hen-sized marsh bird that is long-legged, long-toed, and approximately 14 inches long. It has a slightly down-curved beak and a short, upturned tail. Males and females are identical in plumage. Their cinnamon breast contrasts with the streaked plumage of its grayish brown back and gray and white barred flanks.

The light-footed clapper rail uses southern California coastal salt marshes, lagoons, and their maritime environs. The birds nest in the lower intertidal zone of coastal salt marshes where dense stands of cordgrass (Spartina foliosa) are present. They also build nests in pickleweed (Salicornia virginica). Light-footed clapper rails have also been known to reside and nest in freshwater marshes, although this is not common. They require shallow water and mudflats for foraging, with adjacent higher vegetation for cover during high water .

Light-footed clapper rails inhabit coastal marshes from the Carpinteria Marsh in Santa Barbara County, California, to Bahia de San Quintin, Baja California, Mexico. It is believed that most salt marshes along the coastline at one time supported clapper rails. However, recent census data indicate that less than 50 percent of the coastal wetlands in California are currently occupied. Southern California’s largest subpopulation of light-footed clapper rails, located in the Upper Newport Bay, has been stable since 1980. In contrast, the second and third largest subpopulations at Tijuana Marsh and Seal Beach NWR have been dramatically affected by major environmental disturbances. Very small populations of clapper rails are prone to local disappearance.

Very limited evidence exists for intermarsh movements by light-footed clapper rails. This subspecies is resident in its home marsh except under unusual circumstances. Within marsh movements are also confined and generally of no greater spread than 1,320 feet. Minimum home range sizes for 9 clapper rails that were radio-harnessed for telemetry at Upper Newport Bay varied from approximately 0.8 to 4.1 acres. The larger areas and daily movements were by first year birds attempting to claim their first breeding territories.

Light-footed clapper rails forage in all parts of the saltmarsh, concentrating their efforts in the lower marsh when the tide is out, and moving into the higher marsh as the tide advances. Foraging activity is greatest in the early morning, while vocalizing shows a strong peak just before dark. Activities are also tide-dependent. The rails are omnivorous and opportunistic foragers, which rely mostly on salt marsh invertebrates.

The pair bond in light-footed clapper rails endures throughout the season, and often from year to year. Nesting usually begins in March and late nests have usually hatched by August. Nests are placed to avoid flooding by tides, yet in dense enough cover to be hidden from predators and to support the relatively large nest. Females lay approximately 4-8 eggs, which hatch in 18-27 days. Both parents care for the young; while one forages, the other adult broods the chicks. By the age of two days, chicks will accompany adults on foraging trips, however, adults have been observed feeding fully grown chicks of at least six weeks of age within 80 feet of their incubation nest.

Destruction of coastal wetlands in southern California has been so extensive that many estuaries where light-footed clapper rails were once abundant have been reduced to remnants. Although salt-marsh habitat loss, degradation, and fragmentation are the leading threats to light-footed clapper rails, they are also threatened by disturbance, diseases, contaminants, and predation by non-native red foxes, feral cats, crows, and some hawks or owls. The light-footed clapper rail was federally listed as endangered in 1970. It remains one of California’s birds most endangered with extinction.

The light-footed clapper rail has two nearby concentrations of breeding birds, Anaheim Bay (Seal Beach NWR) and Upper Newport Bay. Bolsa Chica has not supported breeding clapper rails in more than a century, due to the loss of tidal influence and cordgrass. Transient individuals, probably from Anaheim or Newport Bay are occasionally seen at Bolsa Chica, however. Tidal restoration is intended to greatly benefit clapper rail by providing breeding habitat in the tidally influenced areas.