Species Spotlight : Cape Sable Seaside Sparrow
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 AND RANGE
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.
HABITS
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.
FOOD
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
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.
MORTALITY
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.
STATUS AND PROTECTION
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.
Where
you can find Cape Sable Seaside Sparrow