Everglade snail kite: Rostrhamus sociabilis plumbeus
Genus/Species: Rostrhamus sociabilis
Subspecies: Rostrhamus sociabilis plumbeus
Common Name: Everglade snail kite
Federal Status: Endangered
FL Status: Federally-designatedEndangered
FNAI Ranks: G4G5T2/S2 (Globally: Ranges from Apparently Secure to Demonstrably Secure [Insufficient data for specific rank], Sub sp. Imperiled/State: Imperiled)
IUCN Status: Not ranked
The Everglade snail kite is a mid-sized raptor that can reach a length of 14.2-15.4 inches (36-39 centimeters) (Sykes et al. 1995). Males are slate gray with red eyes and orange legs, which turn more reddish during breeding season. Females are brown with red eyes and yellow to orange legs, with varying amounts of white streaking on the face, neck, and chest. Young snail kites are similar in appearance to females except with more cinnamon or buff-colored streaks instead of white (Sykes et al. 1995). Snail kites have a unique curved bill which is used to pluck snails out of their shells.
The Everglade snail kite feeds almost exclusively on apple snails (Pomacea), which are captured at or near the water’s surface. Snail kites hunt for snails by flying slowly or perching over sparsely-vegetated lake shores or marshes, and grabbing snails with their feet that are within six inches (16 centimeters) of the water’s surface.
The Everglade snail kite nests throughout the year, with a peak nesting season between the months of February and July. Males bring food and nesting material as part of their mating behavior (courtship). Other mating displays include flying with a stick in their mouth and vocalizations. The nest is a woven configuration of dry sticks and dry plant material. The sticks are insulated with green nest material that forms a cup to hold the eggs (U.S. Fish & Wildlife Service 1999). Males do most of the nest building which are built over water to reduce access to the nest by predators. Snail kites breed and lay eggs yearly. The Florida population endures a peak egg laying period 81 days before the rainy season in the middle of May, when they can lay up to four eggs per clutch. Both parents share incubation duties as each parent will make a “ku-wak” sound when it is time for a change-over of incubation duties (Sykes 1987).
Habitat and Distribution
Everglade snail kites inhabit shallow freshwater marshes and shallow grassy shorelines of lakes. They can primarily be found in the Kissimmee Valley, St. Johns River headwaters, Lake Okeechobee, Loxahatchee National Wildlife Refuge, Water Conservation Areas 2A, 2B, 3A, 3B, in Broward, Palm Beach and Dade counties; and sections of Big Cypress National Preserve and Everglades National Park (Florida Natural Areas Inventory 2001).
The main threat to the Everglade snail kite in Florida is the loss and degradation of wetlands. The excessive drainage of the Everglades and the increased development of Miami-Dade, Palm Beach, and Broward counties have reduced snail kite habitat over time (U.S. Fish & Wildlife Service 1999). Harassment from humans is also a threat as snail kites will flee from their nest if approached, exposing their eggs or young to predators and harsh temperatures. The spread of large exotic apple snails from South America may affect young snail kites, as they have a harder time eating the adult exotic snails. Also, the degradation of water quality from agriculture and urban runoff alters vegetation and limits the snail kite’s ability to locate food or find nesting substrates (U.S. Fish & Wildlife Service 1999).
Conservation and Management
The Everglade snail kite is protected as an Endangered species by the Federal Endangered Species Act and as a Federally-designated Endangered species by Florida’s Endangered and Threatened Species Rule . The U.S. Fish and Wildlife Service recommends staying at least 500 feet from any active snail kite nest, which are marked with warning signs in areas where human disturbance is likely.
Federal Recovery Plan
Other Informative Links
Florida Natural Areas Inventory
U.S. Fish & Wildlife Service
U.S. Geological Survey
Printable version of this page
Florida Natural Areas Inventory. 2001. Field guide to the rare animals of Florida. http://www.fnai.org/FieldGuide/pdf/Rostrhamus_sociabilis_plumbeus.PDF
Sykes, Jr., P. W., J. A. Rodgers, Jr. and R. E. Bennetts. 1995. Snail Kite (Rostrhamus sociabilis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/171
Sykes, P. W., Jr. 1987. Some aspects of the breeding biology of the snail kite in Florida. Journal Field Ornithology 58:171-189.
U.S. Fish & Wildlife Service. (1999, May 18). Everglade snail kite. Retrieved August 2, 2011, from Multi-Species Recovery Plan for South Florida : http://www.fws.gov/verobeach/MSRPPDFs/EvergladeSnailKite.pdf .
Image Credit Photo by FWC