Florida's Resident Grasshopper Sparrow

Grasshopper sparrows are small, drab, short-tailed birds with a median stripe at the top of a flattened head. Twelve subspecies of the grasshopper sparrow occur in grasslands throughout North America, Central America, and the West Indies.

The Florida grasshopper sparrow is a distinctly dark subspecies native to the south-central prairie region of the state. During the breeding season, Florida grasshopper sparrows are isolated from the eastern subspecies in Georgia by over 300 miles. Other subspecies of migratory grasshopper sparrows also winter in Florida. The resident Florida subspecies requires large treeless grasslands dominated by bunch grasses, low shrubs, and saw palmetto with enough interspersed open areas for this ground-dwelling sparrow to forage effectively. This dry prairie habitat was historically maintained by frequent wildfires which were ignited by lightning and prescribed fires set by cattle ranchers.

Often unnoticed or overlooked because of their small size and cryptic habits, grasshopper sparrows are usually heard before they are seen. From late March to July, males in Florida sing from perches on shrubs and grasses to maintain their breeding territories. The primary song consists of two or three weak introductory notes followed by an insect-like "buzz." A less frequent secondary song is a sustained rambling warble. Adults are sedentary, using the same territory during successive years. Nests are made of grass and are domed. They are usually located in a slight depression in the ground, well-concealed by clumps of dwarf live oak, wire grass, or saw palmetto.

Nest site selection appears to be influenced by the availability of small clumps of dense vegetation for protection within more open areas needed for foraging and predator distraction displays. The female incubates three to five eggs for 11-12 days. Grasshopper sparrow eggs are creamy white with red-brown flecks on the large end. The young grasshopper sparrows are brooded, or nurtured upon hatching, for about eight days. A second or third nesting attempt may be made within the breeding season. Less than 50 percent of the nests are successful in fledging young, or raising the young until they leave the nest. Because the life expectancy of adult Florida grasshopper sparrows averages only three years, a few years of little or no reproduction can result in a drastic population decline.

Historic range (shading) and current distribution (dots) of the Florida Grasshopper Sparrow [+] View Larger Image

The Florida subspecies was first described in 1902 by U.S. Army surgeon, Major Edgar A. Mearns from specimens collected 10 miles south of Lake Kissimmee in Osceola County. Reports from the early 1900s suggest a relatively large, widespread population in south-central Florida. However, a decline in the number of sparrows and a contraction of its range by the 1970s coincided with the conversion of prairie grasslands to improved cattle pastures, sod production, and other agricultural uses. Only about 19 percent of the original dry prairie remains in Florida.

A status survey completed by the Florida Fish and Wildlife Conservation Commission (FWC) in 1985 found 182 Florida grasshopper sparrows at only two locations with a known history of occurrence and seven new sites. Because of its restricted distribution, loss of habitat, and population decline, the Florida grasshopper sparrow was federally listed as endangered in 1986. The sparrow could be reclassified as threatened if at least 50 breeding pairs become established at each of 10 locations within its former range, or removed from endangered status if 25 such sites are established. Despite its listed status, continued habitat loss has nearly wiped out known breeding populations on private land. Surveys in 2004 found only seven occupied locations, with a total estimated population of about 1,000 individuals. Most Florida grasshopper sparrows are located on public lands at Three Lakes Wildlife Management Area (Osceola County), Avon Park Air Force Range (Highlands and Polk counties), and Kissimmee Prairie Preserve State Park (Okeechobee County).

The future management and restoration of prairie grasslands will have important consequences for the recovery of the Florida grasshopper sparrow. Fortunately, the sparrow appears to respond to habitat restoration. Increased densities and nesting success occurs on prairies within one year after a burn. Public land managers maintain dry prairie habitat for Florida grasshopper sparrows with prescribed fire and expand potential habitat by removing encroaching trees. Annual point count surveys are conducted at all populations on public lands to monitor trends and evaluate recovery efforts. Genetic analysis of blood samples collected from the remaining sparrows found that they were closely related, indicating some movement among populations. Florida grasshopper sparrows did not show a low level of genetic variability characteristic of small populations unlikely to recover. A population viability analysis concluded that the subspecies has a 22 percent chance of falling below an extinction threshold of 60 males within the next 50 years.

For more detailed information about Florida Grasshopper Sparrows and related research projects, visit the Publications page. To view photos of the Florida Grasshopper Sparrow and its dry prairie habitat, visit the Photo Gallery.