Rostrhamus sociabilis - (Vieillot, 1817)
Snail Kite
Other Common Names: Gavião-Caramujeiro
Taxonomic Status: Accepted
Related ITIS Name(s): Rostrhamus sociabilis (Vieillot, 1817) (TSN 175295)
French Common Names: Milan des marais
Spanish Common Names: Gavilán Caracolero, Caracolero
Unique Identifier: ELEMENT_GLOBAL.2.102308
Element Code: ABNKC07010
Informal Taxonomy: Animals, Vertebrates - Birds - Other Birds
Image 10601

© Bruce A. Sorrie

 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Accipitriformes Accipitridae Rostrhamus
Genus Size: A - Monotypic genus
Check this box to expand all report sections:
Concept Reference
Help
Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Concept Reference Code: B98AOU01NAUS
Name Used in Concept Reference: Rostrhamus sociabilis
Taxonomic Comments: Prior to 1975, four subspecies were recognized: plumbeus of peninsular Florida; levis of Cuba and the Isle of Pines; major of eastern Mexico, northern Guatemala, and northern Belize; and sociabilis from Nicaragua, Honduras, and Costa Rica southward. Monroe (1968) assigned populations in Honduras to plumbeus. Amadon (1975) combined populations in Florida, Cuba, and the Isle of Pines into one subspecies (plumbeus).

The validity of the nominal subspecies is questionable (Beissinger 1988).
Conservation Status
Help

NatureServe Status

Global Status: G4G5
Global Status Last Reviewed: 19Mar2014
Global Status Last Changed: 28Nov2000
Rounded Global Status: G4 - Apparently Secure
Reasons: Apparently stable in most of the large range; local declines have occurred due mainly to loss and degradation of habitat.
Nation: United States
National Status: N1 (05Jan1997)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Florida (S2)

Other Statuses

Implied Status under the U.S. Endangered Species Act (USESA): PS
Comments on USESA: Subspecies plumbeus is listed by USFWS as Endangered in Florida. Considered Extremely High Priority on 1998 Watch List (Carter et al. 1998).
IUCN Red List Category: LC - Least concern
Convention on International Trade in Endangered Species Protection Status (CITES): Appendix II

NatureServe Global Conservation Status Factors

Range Extent: >2,500,000 square km (greater than 1,000,000 square miles)
Range Extent Comments: RESIDENT: Florida (only parts of the Everglades and Lake Okeechobee are used consistently; range expands during droughts); Cuba (mainly Zapata Swamp area) and Isle of Pines; Pacific lowlands of Oaxaca; locally from Veracruz to Panama; and in South America locally to Bolivia, northern Argentina, Uruguay (Ridgely and Gwynne 1989).

Area of Occupancy: 2,501 to >12,500 4-km2 grid cells
Area of Occupancy Comments: The lower limit is the approximate area in size for south Florida. The upper limit is purely an estimate.

Number of Occurrences: 6 - 300
Number of Occurrences Comments: No rangewide estimates but there are six good EOs in the U.S. (Sykes, Rodgers, and Bennett, 1995) and the population size is "extremely large" (Birdlife International, 2014) so the number of EOs could well be in the hundred.

Population Size: Unknown
Population Size Comments: No rangewide abundance estimates available. Bennetts et al. (1999) estimate about 650 in Florida in 1994 and comment on interpretations of censuses from 1969 through 1994. Other Florida population estimates: 25-60 in the mid-1960s, 250-650 in the early 1980s, 668 in 1984, as low as 326 in 1987; a 1989 survey recorded 464 kites (USFWS 1990). Declines occur during drought years (Snyder and Beissinger 1989); substantial annual fluctuations seem to be typical in Florida (see Johnsgard 1990). The Zapata Swamp population (Cuba) in 1982 was estimated as at least 55 individuals (see Johnsgard 1990).

Number of Occurrences with Good Viability/Integrity: Few to very many (4 to >125)
Viability/Integrity Comments: Should be more than 4 with U.S. population but rest of world is basically unknown.

Overall Threat Impact Comments: Marsh drainage has reduced range in Florida and probably Cuba. Habitat loss and degradation has occurred in coastal areas of Central and South America. Increased demand for freshwater has lowered water levels and dried out wetlands in Florida. Agricultural use of pesticides may pose a serious threat. Exotic plants such as water hyacinth and Australian punktree (MELALEUCA QUENQUINERVIA) are altering Florida habitats to the detriment of the kite. Most pesticide and contaminant research has been done on the U.S. and its potential threat on the global population outside of the U.S. has yet to be assessed.

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Population has declined in Costa Rica in recent years due to habitat destruction (Stiles and Skutch 1989). USFWS (1990) categorized the status of the Florida population as "stable" and this population appears more or less stable in 1988-1994 estimates presented by Bennetts et al. (1999).

Long-term Trend: Decline of <30% to increase of 25%
Long-term Trend Comments: In Florida, habitat and distribution have undergone sharp reduction; by 1967 3131 sq km of the Everglades had been drained. There is no firm evidence, however, of a drastic change in numbers in Central and South America where this species is still common; may have declined in coastal areas.

Intrinsic Vulnerability: Moderately vulnerable to not intrinsically vulnerable.
Intrinsic Vulnerability Comments: Dependent on one genus of snails for its entire diet but the U.S. subspecies of the Snail Kite has shown it is adaptable within that snail genus by now using an exotic snail

Environmental Specificity: Moderate. Generalist or community with some key requirements scarce.
Environmental Specificity Comments: Wetlands are becoming scarcer. The Snail Kite was originally listed as endangered in the U.S. because of the decline of the apple snail native to the U.S. but the Snail Kite has shifted its diet to an exotic snail (Begazo, 2013).

Other NatureServe Conservation Status Information

Inventory Needs: A global estimate of the population of this species may benefit regional conservation efforts.

Protection Needs: During the 1985 drought in Florida, dispersed to scattered wetlands not usually used; preservation of these sites is a new conservation challenge (Takekawa and Beissinger 1989).

Distribution
Help
Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) RESIDENT: Florida (only parts of the Everglades and Lake Okeechobee are used consistently; range expands during droughts); Cuba (mainly Zapata Swamp area) and Isle of Pines; Pacific lowlands of Oaxaca; locally from Veracruz to Panama; and in South America locally to Bolivia, northern Argentina, Uruguay (Ridgely and Gwynne 1989).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States FL

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: NatureServe, 2002; WWF-US, 2000


U.S. Distribution by County Help
State County Name (FIPS Code)
FL Broward (12011), Charlotte (12015), Collier (12021), Glades (12043), Hendry (12051), Indian River (12061), Lake (12069), Lee (12071), Marion (12083), Martin (12085), Miami-Dade (12086), Monroe (12087), Okeechobee (12093), Osceola (12097), Palm Beach (12099), Polk (12105), St. Lucie (12111)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Upper St. Johns (03080101)+, Oklawaha (03080102)+, Vero Beach (03080203)+, Kissimmee (03090101)+, Lake Okeechobee (03090201)+, Everglades (03090202)+, Big Cypress Swamp (03090204)+, Caloosahatchee (03090205)+, Florida Southeast Coast (03090206)+, Charlotte Harbor (03100103)+, Alafia (03100204)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Help
General Description: Adult male is black with white uppertail and undertail coverts, white tail with broad dark band and pale terminal band, orange-red legs, and reddish eyes and facial skin; adult female is dark brown and has patches of white on the forehead and throat, otherwise similar to male; immatures resemble adult females but have boldly streaked head and underparts and paler legs; all have a long hooked bill; averages 43 cm long and 117 cm in wingspan (NGS 1983).
Diagnostic Characteristics: Could be mistaken for a northern harrier or perhaps an eagle or various hawks, but none of these have red feet or red facial skin; the bill of an immature snail kite is longer and more hooked bill than those of similar-looking hawks. Lacks the extensive white on the neck of the crested caracara.
Reproduction Comments: In Florida, the main nesting period is January-August (eggs laid mainly February-April). Clutch size is 2-3 in Florida, 3-4 in Costa Rica. Incubation lasts 26-30 days, by both sexes. Young are tended by both sexes 3-6 weeks, then one adult deserts (female may renest) unless snails are scarce; sustained flight occurs at about 6-7 weeks; fed by parent until age 9-11 weeks. Young fledge at 23-28 days according to Matthews and Moseley (1990); nestling period in Florida averaged 29 days (Johnsgard 1990). First breeds at 1-2 years. Florida: poor nesting success (0-41% in the late 1970s-early 1980s) but population has increased in recent years due to multiple nesting attempts and high survival rates of free-flying individuals (annual adult survivorship probably is over 90%) (Snyder and Beissinger 1989). Nest failures usually are due to drought, structural failure, or predation (e.g., by rat snake). Loose colonial nesting is common; typically defends only the immediate vicinity of the nest (Johnsgard 1990).
Ecology Comments: Tends to be gregarious, especially nonbreeders. Local movements may include long daily flights between communal roost and daily feeding or nesting area.
Non-Migrant: Y
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Some observers report movements that they interpret as migration, but available evidence indicates birds are better characterized as nomadic, moving in response to changes in water level (Palmer 1988, Stiles and Skutch 1989). Some individuals banded in Florida have been found in Cuba.
Lacustrine Habitat(s): Deep water, Shallow water
Palustrine Habitat(s): HERBACEOUS WETLAND, Riparian
Habitat Comments: Florida: large, open freshwater marshes and lakes; open water areas without emergent vegetation required for foraging. Elsewhere: also uses wet savanna, rice fields, flooded fields used for sugar cane (Palmer 1988).

Florida: nests usually 1-5 m above water in low tree or shrub (commonly willow, wax myrtle, pond apple, or cattails), also occasionally sawgrass, maidencane (especially during low water) used for support (Palmer 1988). Usually builds (mainly male) a new nest for each nesting attempt, though may build over old nest or in same location as old nest (Johnsgard 1990).

Adult Food Habits: Invertivore
Immature Food Habits: Invertivore
Food Comments: Eats small, slow-moving, shelled animals. Diet mainly POMACEA snails caught at surface of water (sometimes taken from limpkin--Miller and Tilson 1985); also crabs (DILOCARCINUS) and other snails (MARISA) in South America; small turtles and/or small aquatic snail VIVIPARUS GEORGIANA were eaten during drought in Florida. Searches for food from perch or while flying (Beissinger 1983, Snyder and Kale 1983, Beissinger 1990).
Adult Phenology: Diurnal
Immature Phenology: Diurnal
Length: 43 centimeters
Weight: 380 grams
Economic Attributes Not yet assessed
Help
Management Summary
Help
Management Requirements: Artificial nest supports (wire baskets on poles) have been used successfully to reinforce and stabilize nests in cattails (Palmer 1988).
Monitoring Requirements: See Bennetts et al. (1999) and Palmer (1988) for comments on census methods.
Biological Research Needs: Research into the possible role of contaminants and pesticides in Central and South America affecting those Snail Kite populations is needed because some of those countries have more lax environmental protection laws. Relatively little is known about the biology of the Pomacea snails upon which the Snail Kites depend.
Population/Occurrence Delineation
Help
Group Name: Hawks and Falcons

Use Class: Breeding
Subtype(s): Feeding Area, Nest Site
Minimum Criteria for an Occurrence: Evidence of historical breeding, or current and likely recurring breeding, at a given location, minimally a reliable observation of one or more breeding pairs in appropriate habitat. Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.
Mapping Guidance: If nest site is separated from feeding area by more than 100 meters, map as separate polygons.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 10 km
Separation Distance for Suitable Habitat: 10 km
Separation Justification: Separation distance a compromise between usually relatively small home ranges and obvious mobility of these birds. Home ranges variable, ranging from about 0.5 to about 90 square kilometers; the latter figure refers to nests where birds commuted some distance to feeding grounds. A number of studies give mean home ranges on the order of 7 square kilometers, which equates to a circle with a diameter of about 3 kilometers; three times that home range gives a separation distance of about 10 kilometers. Home ranges: Ferruginous Hawk, mean 5.9 square kilometers in Utah (Smith and Murphy 1973); range 2.4 to 21.7 square kilometers, mean 7.0 square kilometers in Idaho (Olendorff 1993); mean 7.6 square kilometers in Idaho (McAnnis 1990); mean 90 square kilometers in Washington (Leary et al. 1998); Red-tailed Hawk, most forage within 3 kilometers of nest (Kochert 1986); mean spring and summer male home ranges 148 hectares (Petersen 1979); Hawaiian Hawk, 48 to 608 hectares (n = 16; Clarkson and Laniawe 2000); Zone-tailed Hawk, little information, apparent home range 1-2 kilometers/pair in west Texas (Johnson et al. 2000); White tailed Kite, rarely hunts more than 0.8 kilometers from nest (Hawbecker 1942); Prairie Falcon, 26 square kilometers in Wyoming (Craighead and Craighead 1956), 59 to 314 square kilometers (reported by Steenhof 1998); Aplomado Falcon, 2.6 to 9.0 square kilometers (n = 5, Hector 1988), 3.3 to 21.4 square kilometers (n = 10, Montoya et al. 1997). Nest site fidelity: high in Zone-tailed Hawk; all seven west Texas nesting territories occupied in 1975 were reused in 1976 (Matteson and Riley 1981). Swainson's Hawk: In California, dispersal distances from natal sites to subsequent breeding sites ranged from 0 to 18 kilometers, mean 8.8 kilometers (Woodbridge et al. 1995); in contrast, none of 697 nestlings in Saskatchewan returned to the study area; three were found 190, 200 and 310 kilometers away (Houston and Schmutz 1995).
Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 3 km
Inferred Minimum Extent Justification: Foraging range variable; 3 kilometers is the mean diameter in several species.
Date: 13Mar2001
Author: Cannings, S.

Use Class: Nonbreeding
Subtype(s): Foraging area, Roosting area
Minimum Criteria for an Occurrence: Evidence of recurring presence of wintering birds (including historical); and potential recurring presence at a given location, usually minimally a reliable observation of 5 birds (this can be reduced to 1 individual for rarer species). Occurrences should be locations where the species is resident for some time during the appropriate season; it is preferable to have observations documenting presence over at least 20 days annually. Be cautious about creating EOs for observations that may represent single events.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 10 km
Separation Distance for Suitable Habitat: 10 km
Separation Justification: Separation distance somewhat arbitrary; set at 10 kilometers to define occurrences of managable size for conservation purposes. However, occurrences defined primarily on the basis of areas supporting concentrations of foraging birds, rather than on the basis of distinct populations.
Date: 15Apr2002
Author: Cannings, S.
Population/Occurrence Viability
Help
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Help
Authors/Contributors
Help
NatureServe Conservation Status Factors Edition Date: 19Mar2014
NatureServe Conservation Status Factors Author: Jue, Dean K.
Element Ecology & Life History Edition Date: 29Mar1995
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

  • American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.

  • Begazo, A. 2013. The Everglades Snail Kite is Making a Comeback.  Online at: http://10000birds.com/the-everglade-snail-kite-is-making-a-comeback.htm (Accessed on 23-April 2014).

  • Begazo, Alfredo.  2013.  The Everglades Snail Kite is Making a Comeback.  Accessd online at http://10000birds.com/the-everglade-snail-kite-is-making-a-comeback.htm.  Accessed on 23-April 2014.

  • Beissinger, S. R. 1983. Hunting behavior, prey selection, and energetics of snail kites in Guyana: consumer choice by a specialist. Auk 100:84-92.

  • Beissinger, S. R. 1988. Snail Kite. Pages 148-165 in Handbook of North American birds, vol. 4 (R. S. Palmer, editor.). Yale University Press, New Haven, CT.

  • Beissinger, S. R. 1990a. Alternative foods of a diet specialist, the snail kite. Auk 107:327-333.

  • Beissinger, S. R. 1990b. Experimental brood manipulation and the monoparental threshold in snail kites. Am. Nat. 136:20-38.

  • Beissinger, S. R. 1995. Modeling extinction in periodic environments: Everglades water levels and snail kite population viability. Ecological Applications 5:618-631.

  • Bennetts, R. E., S. McGehee, and W. M. Kitchens. 1992. 1992 mid-winter snail kite survey. Cooperative Fish and Wildlife Research Unit Report, December 1992, 10pp.

  • Bennetts, R. E., W. A. Link, J. R. Sauer, and P. W. Sykes, Jr. 1999. Factors influencing counts in an annual survey of Snail Kites in Florida. Auk 116:316-323.

  • Bent, A.C. 1937. Life histories of North American birds of prey. Part 1. Bull. U.S. Natl. Mus. 137. 409 pp.

  • BirdLife International (2013-2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on various dates in 2013 and 2014. http://www.birdlife.org/.

     

  • BirdLife International. (2013-2014). IUCN Red List for birds. Downloaded from http://www.birdlife.org on various dates in 2013 and 2014. http://www.birdlife.org/

  • BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.

  • Braun, M. J., D. W. Finch, M. B. Robbins, and B. K. Schmidt. 2000. A field checklist of the birds of Guyana. Smithsonian Institution, Washington, D.C.

  • Carter, M., C. Hunter, D. Pashley, and D. Petit. 1998. The Watch List. Bird Conservation, Summer 1998:10.

  • Clarkson, K. E. and L. P. Laniawe. 2000. Hawaiian Hawk, Buteo solitarius. In A. Poole and F. Gill, editors. The Birds of North America. No. 523. The Birds of North America, Inc., Philadelphia, PA. 16 pp.

  • Craighead, J. J., and F. C. Craighead, Jr. 1956. Hawks, Owls and Wildlife. The Stackpole Company, Harrisburg, Pennsylvania, and the Wildlife Management Institute, Washington, D.C.

  • Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1992. Birds in Jeopardy: the Imperiled and Extinct Birds of the United States and Canada, Including Hawaii and Puerto Rico. Stanford University Press, Stanford, California. 259 pp.

  • England, A. S., M. J. Bechard, and C. S. Houston. 1997. Swainson's Hawk (Buteo swainsoni). No. 265 IN A. Poole and F. Gill, editors, The birds of North America. The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, DC. 28pp.

  • Fisher, A.K. 1893. The hawks and owls of the United States in their relation to agriculture. Washington U.S. Dept. of Agriculture Bull. no. 6. 210 pp.

  • Garrido, O. H. and A. Kirkconnell. 2000. Field guide to the birds of Cuba. Cornell University Press, Ithaca, New York.

  • Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.

  • Hawbecker, A. C. 1942. A life history study of the white-tailed kite. Condor 44:267-276.

  • Hector, D. P. 1988b. Aplomado Falcon (Falco femoralis). Pages 315-322 in R. S. Palmer, editor, Handbook of North American birds. Vol. 5: Family Accipitridae, Family Falconidae. Yale University Press, New Haven, Connecticut.

  • Houston, C. S., and J. K. Schmutz. 1995. Swainson's Hawk banding in North America to 1992. North American Bird Bander 20:120-127.

  • Howell, S. N. G., and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, Oxford, UK.

  • Johnsgard, P. A. 1990. Hawks, eagles, and falcons of North America. Smithsonian Inst. Press, Washington, D.C. xvi + 403 pp.

  • Johnson, R. R., R. L. Glinski, and S. W. Matteson. 2000. Zone-tailed Hawk (Buteo albonotatus). No. 529 IN A. Poole and F. Gill, editors, The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 20pp.

  • Kochert, M. N. 1986. Raptors. pages 313-349 IN: A. Y. Cooperrider, R. J. Boyd, and H. R. Stuart, editors. Inventory and monitoring of wildlife habitat. Denver, CO: U.S. Department of the Interior, Bureau of Land Management, Denver Service Center.

  • Leary, A. W., R. Mazaika, and M. J. Bechard. 1998. Factors affecting the size of Ferruginous Hawk home ranges. Wilson Bulletin 110:198-205.

  • Matteson, S. W., and J. O. Riley. 1981. Distribution and nesting success of Zone-tailed Hawks in west Texas. Wilson Bulletin 107:719-723.

  • Matthews, J.R. and C.J. Moseley (eds.). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index. Volume 2. Birds, Reptiles, Amphibians, Fishes, Mussels, Crustaceans, Snails, Insects, and Arachnids. xiii + pp. 561-1180. Beacham Publications, Inc., Washington, D.C.

  • Miller, B. W., and R. L. Tilson. 1985. Snail kite kleptoparasitism of limpkins. Auk 102:170-171.

  • Monroe, B.L., Jr. 1968. A distributional survey of the birds of Honduras. Ornithological Monographs 7:1-458.

  • Montoya, A.B., P.J. Zwank, and M. Cardenas. 1997. Breeding biology of Aplomado Falcons in desert grasslands of Chihuahua, Mexico. Journal of Field Ornithology 68(1):135-143.

  • National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.

  • Olendorff, R. R. 1993. Status, biology, and management of Ferruginous Hawks: a review. Raptor Res. and Tech. Asst. Cen., Special Report. U.S. Dept. Interior, Bureau of Land Management, Boise, Idaho. 84 pp.

  • Palmer, R. S., editor. 1988a. Handbook of North American birds. Vol. 4. [Diurnal raptors, part 1]. Yale University Press, New Haven, CT. vii + 433 pp.

  • Parker III, T. A., D. F. Stotz, and J. W. Fitzpatrick. 1996. Ecological and distributional databases for neotropical birds. The University of Chicago Press, Chicago.

  • Pendleton, B. A. G., B. A. Millsap, K. W. Cline, and D. M. Bird. 1987. Raptor management techniques manual. National Wildlife Federation, Sci. and Tech. Ser. No. 10. 420 pp.

  • Petersen, L. 1979. Ecology of Great Horned Owls and Red-tailed Hawks in southeastern Wisconsin. Wisconsin Department of Natural Resources Technical Bulletin no. 111.

  • Petracci, P. F. and D. Basanta. 2002. Efectos positivos de la nidificación del Macá Común (Rollandia rolland) en una colonia de Caracoleros (Rostrhamus sociabilis). Ornitologia Neotropical 13:113-119.

  • Raffaele, H., J. Wiley, O. Garrido, A. Keith, and J. Raffaele. 1998. A guide to the birds of the West Indies. Princeton University Press, Princeton, NJ. 511 pp.

  • Reichert, Brian E., Christopher E. Cattau, Robert J. Fletcher, Jr., P. W. Sykes, Jr., J. A. Rodgers, Jr. and R. E. Bennetts. 2015. 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.bnaproxy.birds.cornell.edu/bna/species/171
    doi:10.2173/bna.171

  • Ridgely, R. S. 2002. Distribution maps of South American birds. Unpublished.

  • Ridgely, R. S., and J. A. Gwynne, Jr. 1989. A guide to the birds of Panama with Costa Rica, Nicaragua, and Honduras. Second edition. Princeton Univ. Press, Princeton, New Jersey. 534 pp.

  • Rodgers, J. A., Jr., H. W. Kale, III, and H. T. Smith. 1996. Rare and endangered biota of Florida. Volume V. Birds. University Press of Florida. 736pp.

  • Sibley, D. A. 2000a. The Sibley guide to birds. Alfred A. Knopf, New York.

  • Smith, D. G., and J. R. Murphy. 1973. Breeding ecology of raptors in the eastern Great Basin of Utah. Brigham Young University Science Bulletin, Biol. Ser. 13:1-76.

  • Snyder, N. F. R., S. R. Beissinger, and R. E. Chandler. 1989. Reproduction and demography of the Florida Everglade (snail) kite. Condor 91:300-316.

  • Snyder, N. F. R., and H. W. Kale, II. 1983. Mollusk predation by snail kites in Colombia. Auk 100:93-97.

  • Steenhof, K. 1998. Prairie Falcon (Falco mexicanus). In A. Poole and F. Gill, editors, The Birds of North America, No. 346. The Birds of North America, Inc., Philadelphia, PA. 28 pp.

  • Stevenson, H.M., and B.H. Anderson. 1994. The Birdlife of Florida. University Press of Florida, 891 pp.

  • Stiles, F. G. and A. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, New York, USA. 511 pp.

  • 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 Laboratory of Ornithology; Retrieved from the Birds of North America Online:  http://bna.birds.cornell.edu.bnaproxy.birds.cornell.edu/bna/species/171/doi:10.2173/bna.171.

  • Sykes, P.W., Jr., J.A. Rodgers, Jr., and R.E. Bennetts. 1995. Snail Kite (Rostrhamus sociabilis). In A. Poole and F. Gill, editors, The Birds of North America, No. 171. Academy of Natural Sciences, Philadelphia, and American Ornithologists' Union, Washington, DC. 32 pp.

  • Takekawa, J. E., and S. R. Beissinger. 1989. Cyclic drought, dispersal, and the conservation of the snail kite in Florida: lessons in critical habitat. Conserv. Biol. 3:302-311.

  • Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.

  • U.S. Fish and Wildlife Service (USFWS). 1980. Selected vertebrate endangered species of the seacoast of the United States-- the Florida Everglade kite. FWS/OBS-80/01.32. 5 pp.

  • U.S. Fish and Wildlife Service (USFWS). 1986. Florida snail kite (Rostrhamus sociabilis plumbeus Ridgeway) revised recovery plan (formerly called the Everglade kite). 57 pp.

  • U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and threatened species recovery program: report to Congress. 406 pp.

  • Woodbridge, B., K. K. Finley, and P. H. Bloom. 1995. Reproductive performance, age structure, and natal dispersal of Swainson's Hawks in the Butte Valley, California. Journal of Raptor Research 29:187-192.

  • Zook, J. L. 2002. Distribution maps of the birds of Nicaragua, Costa Rica, and Panama. Unpublished.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at http://explorer.natureserve.org were updated to be current with NatureServe's central databases as of March 2018.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2018 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.