Index of Species Information

WILDLIFE SPECIES:  Drymarchon corais

Introductory

WILDLIFE SPECIES: Drymarchon corais
AUTHORSHIP AND CITATION : Snyder, S. A. 1993. Drymarchon corais. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [].
ABBREVIATION : DRCO COMMON NAMES : indigo snake American corais snake blue bull snake blue gopher snake Couper's snake Georgia snake TAXONOMY : The currently accepted scientific name for the indigo snake is Drymarchon corais. It is in the family Colubridae. Subspecies of indigo snake occurring in the United States are [11]: D. corais couperi (eastern indigo snake) D. corais erebennus (Texas indigo snake) ORDER : Squamata CLASS : Reptile FEDERAL LEGAL STATUS : The eastern indigo snake (Drymarchon corais couperi) is federally listed as Threatened [13]. OTHER STATUS : The eastern indigo snake continues to decline throughout its range in Georgia, Florida, Alabama, and South Carolina [9]. The state of Florida lists it as threatened [12].


WILDLIFE DISTRIBUTION AND OCCURRENCE

WILDLIFE SPECIES: Drymarchon corais
GENERAL DISTRIBUTION : The eastern indigo snake ranges from southern South Carolina south through Florida and west to Louisiana, Mississippi, and Alabama. The Texas indigo snake is found in southern Texas and Mexico [11]. ECOSYSTEMS : FRES12 Longleaf-slash pine FRES13 Loblolly-shortleaf pine FRES32 Texas savanna STATES :
AL FL GA MS SC TX MEXICO
BLM PHYSIOGRAPHIC REGIONS : NO-ENTRY KUCHLER PLANT ASSOCIATIONS : K061 Mesquite - acacia savanna K062 Mesquite - live oak savanna K078 Southern cordgrass prairie K079 Palmetto prairie K080 Marl - everglades K091 Cypress savanna K092 Everglades K112 Southern mixed forest K113 Southern floodplain forest K115 Sand pine scrub K116 Subtropical pine forest

SAF COVER TYPES : 66 Ashe juniper - redberry (Pinchot) juniper 68 Mesquite 70 Longleaf pine 71 Longleaf pine - scrub oak 72 Southern scrub oak 81 Loblolly pine 82 Loblolly pine - hardwood 84 Slash pine 85 Slash pine - hardwood 89 Live oak 104 Sweetbay - swamp tupelo - redbay 105 Tropical hardwoods 111 South Florida slash pine 241 Western live oak SRM (RANGELAND) COVER TYPES : NO-ENTRY PLANT COMMUNITIES : The indigo snake is most abundant in the sandhill plant communities of Florida and Georgia. These communities are primarily scrub oak-longleaf pine (Pinus palustris) with occasional live oak (Quercus virgianiana), laurel oak (Q. laurifolia), Chapman's oak (Q. chapmanii), and myrtle oak (Q. myrtifolia). Other communities include longleaf pine-turkey oak (Q. laevis), slash pine (Pinus elliottii)-scrub oak, pine flatwoods, and pine-mesic hardwoods [1].

BIOLOGICAL DATA AND HABITAT REQUIREMENTS

WILDLIFE SPECIES: Drymarchon corais
TIMING OF MAJOR LIFE HISTORY EVENTS : Indigo snakes can grow as long as 125 inches (262 cm). They mate from November through March with a peak in mid-November through late December. The age of sexual maturity is unknown [9]. An average of 3 to 10 eggs are laid in March through July; eggs hatch from May through October [10]. The average life span of the indigo snake is 11 years, although they can live as long as 21 years [11]. They do not hibernate and remain somewhat active during winter, especially if temperatures are higher than 50 degrees Fahrenheit (10 deg C) [9]. PREFERRED HABITAT : Indigo snakes frequent flatwoods, hammocks, dry glades, stream bottoms, cane fields, riparian thickets, and high ground with well-drained, sandy soils [11]. In Georgia, snakes prefer excessively drained, deep sandy soils along major streams, as well as xeric sandridge habitats [1]. Xeric slash pine plantations seem to be preferred over undisturbed longleaf pine habitats [6]. Habitat selection varies seasonally. From December to April indigo snakes prefer sandhill habitats; from May to July snakes shift from winter dens to summer territories; from August through November they are located more frequently in shady creek bottoms than during other seasons [9]. COVER REQUIREMENTS : Because the cover requirements of indigo snakes change seasonally, maintaining corridors that link the different habitats used is important. From the spring through fall snakes must be able to travel from sandhill communities and upland pine-hardwood communities to creek bottoms and agricultural fields [9]. In winter indigo snakes den in gopher tortoise burrows, which are usually found in open pine forests with dense herbaceous understories [6]. Burrows need to be in areas where there is no flooding. Indigo snakes also heavily use debris piles left from site-preparation operations on tree plantations [6]. These piles are often destroyed for cosmetic reasons but should be left intact because they provide important hiding cover for both the snake and its prey. Summer home ranges for the indigo snake can be as large as 273 acres (229 ha) [9]. FOOD HABITS : Indigo snakes eat other snakes, turtles, lizards, frogs, toads, a variety of small birds and mammals, and eggs [6,11]. PREDATORS : Humans represent the biggest threat to indigo snakes. Highway fatalities, wanton killings, and overcollection for the pet trade adversely affect indigo snake populations. Snakes are taken illegally from the wild and sold as pets for as much as $250 each. Snakes are also inadvertantly gassed in their burrows by rattlesnake hunters [1]. MANAGEMENT CONSIDERATIONS : Indigo snakes are a commensal species associated with gopher tortoises. Snakes use abandoned tortoise burrows heavily in the winter and spring [1]. For this reason it is necessary to maintain healthy tortoise populations, also a species in decline throughout its range. Because slash piles are used by snakes for hiding and foraging, this debris should be left intact on pine plantations [6]. Speake and others [9] recommend protecting several thousand hectares of prime indigo snake habitat to ensure the snakes' year-round needs are met. Some important sandhill communities of Georgia and Florida are being replaced by slash pine plantations, which can support a few snakes if burned and planted with wide spacing to encourage gopher tortoise populations [6]. Recommendations for captive breeding of indigo snakes are as follows [10]: Captive snakes should be released to the wild after 2 to 3 years, and new snakes from the wild should be introduced to the captive population, preferably every winter. This is important because wild snakes seem to grow faster and produce more young than snakes held in captivity. Because smaller snakes do not use tortoise burrows, they should be released in wetland areas with plenty of herbaceous cover near the water's edge. Hatchlings will den in areas with dense saw palmetto (Serenoa repens) and should be released near these areas.

FIRE EFFECTS AND USE

WILDLIFE SPECIES: Drymarchon corais
DIRECT FIRE EFFECTS ON ANIMALS : Because hatchlings do not use tortoise burrows they may be susceptible to fire mortality. However, adult snakes may be able to escape fires while in their burrows [10]. HABITAT RELATED FIRE EFFECTS : Fire exclusion in southern pine-scrub oak habitats is a major cause of habitat degredation for gopher tortoise and, therefore, indigo snakes [6]. The absence of fire allows oaks to mature and leaf litter to accumulate, making burrow digging difficult and herbaceous food scarce. Studies of herpetofauna in Florida sandhill commmunities showed higher species diversity in young sand pine (Pinus clausa)-scrub oak habitats, which are maintained by frequent fire [7]. Experimental burns in these communities showed snakes used plots burned at 2- and 7-year intervals more than plots left unburned or burned yearly. The effects of different season burns on gopher tortoises in Ocala National Forest, Florida, showed more burrows in July-burned areas than in February-burned areas at the first postfire year [8]. Preburn densities of gopher tortoise were not determined. FIRE USE : Landers and Speake [6] recommend burning indigo snake habitats every 2 years to maintain a young, open overstory and an abundant herbaceous understory. This will provide good gopher tortoise habitat, which in turn will provide burrows for snakes. Burning sandhill communities every 2 to 4 years will maintain open longleaf pine stands with understories of wiregrass (Aristida stricta) and turkey oak [6]. Burning in late summer where young indigo snakes have been released from captive breeding programs is not recommended because young snakes depend on dense herbaceous vegetation for cover instead of burrows [10].

REFERENCES

WILDLIFE SPECIES: Drymarchon corais
REFERENCES : 1. Diemer, Joan E.; Speake, Dan W. 1983. The distribution of the eastern indigo snake, Drymarchon corais couperi, in Georgia. Journal of Herpetology. 17(3): 256-264. [21093] 2. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 3. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 4. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 5. Landers, J. Larry. 1987. Prescribed burning for managing wildlife in southeastern pine forests. In: Dickson, James G.; Maughan, O. Eugene, eds. Managing southern forests for wildlife and fish: a proceedings; [Date of conference unknown]; [Location of conference unknown]. Gen. Tech. Rep. SO-65. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station: 19-27. [11562] 6. Landers, J. Larry; Speake, Dan W. 1980. Management needs of sandhill reptiles in southern Georgia. Proceedings, Annual Conference of Southeast Association Fish & Wildlife Agencies. 34: 515-529. [21092] 7. Mushinsky, Henry R. 1985. Fire and the Florida sandhill herpetofaunal community: with special attention to responses of Cnemidophorus sexlineatus. Herpetologica. 41(3): 333-342. [11953] 8. Robbins, Louise E.; Myers, Ronald L. 1992. Seasonal effects of prescribed burning in Florida: a review. Misc. Publ. No. 8. Tallahassee, FL: Tall Timbers Research, Inc. 96 p. [21094] 9. Speake, Dan W.; McGlincy, Joe A.; Colvin, Thagard R. 1978. Ecology and management of the eastern indigo snake in Georgia: a progress report. In: Odum, R. R.; Landers, L., eds. Proceedings, Rare and endangered wildlife symposium. Tech. Bull. WL4. Atlanta, GA: Georgia Department of Natural Resources, Game and Fish Division: 64-73. [21090] 10. Speake, Dan; McGlincy, Donna; Smith, Cynthia. 1987. Captive breeding and experimental reintroduction of the eastern indigo snake. In: Proceedings, 3rd Southeast nongame and endangered wildlife symposium: 84-88. [21091] 11. Conant, Roger; Collins, Joseph T. 1991. A field guide to reptiles and amphibians: Eastern and central North America. 3rd ed. Peterson Field Guide Series No. 12. Boston: Houghton Mifflin Company. 450 p. [22902] 12. Wood, Don A., compiler. 1994. Official lists of endangered & potentially endangered fauna and flora in Florida. Tallahassee, FL: Florida Game and Fresh Water Fish Commission. 22 p. [24196] 13. U.S. Fish and Wildlife Service. 2013. Listed animals. In: Environmental Conservation Online System, [Online]. In: Species reports. Available: http://ecos.fws.gov/tess_public/pub/listedAnimals.jsp. [86534]


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