Researchers study the endangered sparrow and its habitat to provide data that aids recovery efforts.
|Researchers are concerned
by the grasshopper sparrow’s
rapid population decline.
The next few years will be crucial for the Florida grasshopper sparrow, a little-known endangered bird whose numbers have inexplicably declined. Point count surveys in 2012 detected only 75 singing males, down from 233 counted just four years earlier. Even accounting for imperfect detection of this cryptic sparrow and including remnant populations on private lands, fewer than 500 individuals may remain. Scientists and land managers are unsure of the cause of the decline. According to land managers, prairies on public lands managed for the sparrow appear the same as they were 30 years ago, when the bird’s population seemed to be more stable.
Biologists monitor Florida grasshopper sparrows each year during the breeding season, April through June, at an array of survey stations on public lands where populations exist. They listen for singing males establishing territories and look for Florida grasshopper sparrows perched on shrubs and barbed-wire fences.
The Florida grasshopper sparrow is one of four recognized subspecies of grasshopper sparrow in the U.S. During the breeding season, approximately 300 miles separate the Florida subspecies from grasshopper sparrows in Georgia. The Florida grasshopper sparrow is an isolated grassland bird, and this restricted distribution makes it especially susceptible to habitat loss.
Grasshopper sparrows are small, short-tailed birds approximately 5 inches long. They are named for their “buzzy” song, which sounds like a grasshopper. Feathers at the bend of the wing are bright yellow and a small patch of orange appears in front of the eyes. A white stripe marks the top of the head, while feathers on the back are a richly mottled dark brown, black and gray. The Florida subspecies is much darker in feather coloration than other grasshopper sparrows.
|Florida's dry prairies are extensive treeless areas dominated by grass and low shrubs. Only about 19 percent of this habitat remains, so management of dry prairie is important for Florida grasshopper sparrow conservation.
Restricted to the south-central prairie region of the state, Florida grasshopper sparrows are habitat specialists that require large areas of native grassland. Records from the early 1900s indicate the species was once more abundant and widespread in distribution within the Kissimmee River basin. Because of a suspected population decline, the state of Florida classified the Florida grasshopper sparrow as endangered in 1978. Much of the bird’s native prairie habitat has been converted for improved cattle pasture and other agricultural uses, eliminating the subspecies from some of its former range. Further reduction in distribution and abundance led the U.S. Fish and Wildlife Service to list the Florida grasshopper sparrow as endangered in 1986.
Florida grasshopper sparrows can be seen during the breeding season at Three Lakes Wildlife Management Area in Osceola County and Kissimmee Prairie Preserve State Park in Okeechobee County. Florida grasshopper sparrow conservation is a management priority on these lands and Avon Park Air Force Range in Highlands and Polk counties. Managers apply prescribed fire to maintain dry prairie in an open, early successional stage for this ground-dwelling bird; encroaching woody vegetation is removed to preserve the large grasslands the sparrow requires.
The rate of the sparrow’s decline is cause for concern, making recovery efforts especially important. Researchers and managers will use future surveys to monitor populations and evaluate management actions. Nesting and banding studies planned for the 2013 breeding season at Three Lakes Wildlife Management Area are designed to identify causes of the population decline to guide recovery. FWC members of the Florida Grasshopper Sparrow Working Group are coordinating emergency efforts with other members, including the Florida Department of Environmental Protection, U.S. Fish and Wildlife Service, Avon Park Air Force Range, University of Florida, University of Central Florida, Archbold Biological Station and Tall Timbers Research Station.
Audio - songs of the Florida grasshopper sparrow