Cape Sable Seaside Sparrow: Ammodramus maritimus mirabilis

Appearance:

The Cape Sable seaside sparrow is the only bird restricted entirely to the Everglades ecosystem. The 5-inch-long sparrow is dark olive-gray and brown on the back and light gray with dark olive streaks on the sides. It has small patches of yellow feathers in front of the eyes and at the bend of the wings. Because of their small size, drab appearance, and secretive habits, seaside sparrows usually are heard before they are seen. The male's song consists of a few introductory notes followed by a "buzzy" trill.

Habitat:

The non-migratory Cape Sable seaside sparrow occurs almost exclusively in Everglades National Park and Big Cypress National Preserve in Dade and Monroe counties. Seaside sparrows are normally found along the coast, however, this subspecies occupies seasonally flooded inland prairies of muhly grass, short sawgrass, and cordgrass. Areas of dense cordgrass, cattail, and shrubs are avoided. The sparrow has not been found on Cape Sable since the 1970s due to habitat changes.

Behavior:

The Cape Sable seaside sparrow is adapted to a life in vegetation that is periodically burned and flooded. Fires and flooding maintain suitable habitat by preventing the invasion of shrubs and trees. However, fires and high water levels during the nesting season can threaten eggs and recently fledged young. The Cape Sable seaside sparrow is sometimes called the "Goldilocks bird" because conditions have to be just right for its survival.

Cape Sable seaside sparrows are dietary generalists, taking advantage of any food available as they forage low in the grass and on the ground. They feed on grasshoppers, caterpillars, beetles, spiders, and grass and sedge seeds. Adults remove the legs and wings from insects before feeding them to their young.

Nesting can occur from February through August with most occurring during April and May. The time and length of the nesting season depends on flooding. Nesting will be delayed or ended if water levels are too high. Males sing from the tops of grass stems early in the morning during the nesting season. Nests are constructed in clumps of grass about 6 inches above the ground. Usually 3-4 eggs are laid. The female incubates the eggs for 12 days and young fledge at 9-11 days old. Two or three nests are attempted each season with a success rate of 40-75%. The sparrow's high reproductive potential help it persist in a variable habitat.

Some nests are lost to flooding and fires. Raccoons, snakes, rice rats and hawks are probably predators of Cape Sable seaside sparrows. Predation by a cottonmouth has been documented.

The Cape Sable seaside sparrow was classified as endangered by the U.S. Fish and Wildlife Service and the Florida Fish and Wildlife Conservation Commission because of its low numbers, limited distribution, and threats to its habitat. Areas of critical habitat were designated for the sparrow. There were an estimated 6,656 Cape Sable seaside sparrows in 1981, but annual surveys since 1992 indicate a decline to an estimated 2,624 birds by 2002. Habitat is maintained by prescribed fire, and water levels are regulated to benefit the sparrow. However, water management in the Everglades has been controversial because of possible negative impacts on other endangered species and human land uses.

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