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Antigone canadensis pratensis (F.A.A. Meyer, 1794)
Florida Sandhill Crane
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G5T2
State Rank: S1
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: High Conservation Concern
Element Occurrences (EOs) in Georgia: 4
Habitat Summary for element in Georgia: Freshwater marshes; bays; fields. Only known from Okefenokee NWR (recent surveys outside swamp detected no birds)
The Florida sandhill crane is a tall bird at nearly four feet in height. Neck, body, and wings of adults are gray, often with a rusty wash on the lower neck, back, and upper wings. Interestingly, this rusty color is not the result of feather pigmentation, but rather from staining caused by preening with soils that contain iron oxide. The cheek is white with a bright red crown present on adults of both sexes. Legs are dark gray to black. The bill is long, dagger-like, and grayish in color. Eyes are red to yellow.
The greater sandhill crane (Antigone canadensis tabida) is indistinguishable from the Florida sandhill crane in the field. Greater sandhill cranes winter in South Georgia, including the Okefenokee NWR, and in Florida. They can be present from late October through early March. Sandhill cranes seen in the Okefenokee from late March through September are assumed to be Florida sandhill cranes. Another bird that is often confused with the sandhill crane is the great blue heron (Ardea herodius), which has a blue-gray body and wings, light grayish neck, white head with black plume extending off the back, and yellow bill. The great blue heron lacks the red crown.
In Florida this subspecies nests in shallow herbaceous wetlands (bulrushes, cattails, sedges, grasses, and other aquatic plants) and uses ranchland, pastures, grasslands, crop fields, golf courses, subdivisions, and open forest for feeding. Nesting territories in Florida are very large, often encompassing areas as large as 250 ha (625 acres). In the Okefenokee this bird uses aquatic macrophyte, herbaceous, and shrub-scrub prairie habitats year-round. Nesting occurs in all three of these habitat types and nest placement within these habitats is heavily influenced by water depth. In drier years a higher proportion of nests are placed in macrophyte habitats, which have deeper average depths, while in wet years more nests are placed in shrub-scrub habitats, which are drier than macrophyte and herbaceous prairie habitats. Nesting territories here average about 20 ha (~50 acres).
Florida sandhill cranes are omnivorous, feeding by probing into the soil and by gleaning food from the surface in shallow water wetlands, grasslands, or fields. They eat aquatic and terrestrial invertebrates, waste grain, acorns, roots and tubers, crayfish, frogs, snakes, nestling birds, and small mammals. Resident birds in the Okefenokee NWR eat mostly animal foods during the summer months (May-October) including insects, crustaceans, amphibians, small fish, and reptiles. A study in the 1980s found that frogs, including the southern cricket frog (Acris gryllus), pig frog (Lithobates gyrlio), and southern leopard frog (Lithobates sphenocephalus), and katydid grasshoppers were the major prey items. Cranes also ate snakes (unknown spp.), topminnows (Fundulus spp.), sirens (Siren spp.), amphiumas (Amphiuma means), crayfish (Procambarus spp.), and young round-tailed muskrats (Neofiber alleni). During fall and winter (November-February), cranes fed primarily on tubers and seeds, particularly the tubers of red root (Lachnanthes caroliniana), but also tubers of arrowhead (Sagittaria graminea), nutgrass (Cyperus sp.), and grasspink (Calopogon pulchallus). Beakrush (Rynchospora inundata) was the most significant seed source eaten during the fall and winter months.
The Florida sandhill crane is monogamous, usually forming life-long pair bonds. However, if one member of the pair dies the other will often find another mate, and occasionally “divorce” occurs. The nesting season in the Okefenokee is usually four months long, normally starting in early March with final nests often hatching in late June. However, timing of nesting can be influenced by air temperature and is heavily influenced by water levels. Renesting after nest failure is common and normally two or three nesting cycles occur. During a multi-year study, researchers found that in years with sufficient water more than 60% of all nests were initiated in a 15-day period from March 10-25. Initiation of second nesting attempts peaked from 14-24 April, and third nesting attempts in late May. During a drought year only a single peak of nesting activity was observed and this was in early April, more than a week later than the first peak normally seen in non-drought years. Nests are constructed from sticks and herbaceous vegetation that immediately surrounds the nest site. Those built on dry substrates are generally smaller than nests constructed over water. Auxiliary nest platforms are often constructed nearby for brooding young or to provide the young a place to rest. Usually two eggs (range 1-3 eggs) are laid 2-3 days apart. Hatching occurs about 29-32 days later. Both parents share incubation duties equally during daylight hours; however, only the female incubates at night. Within 24 hours of hatching the young can leave the nest. Young are fed by the parents until they are about half grown, although they will occasionally beg until independence. Fledging takes place at about 67-75 days after hatching, but young remain with their parents until 9-10 months old.
Since 2012, DNR has conducted helicopter surveys of nesting Florida sandhill cranes in the Okefenokee NWR. Unfortunately, the survey designs used from 2012-2013 and 2014-2017 were inadequate to draw statistically meaningful inferences about population size and trends. However, they did provide data that was used to aid the design of a statistically robust survey methodology now in place. This design includes transects spaced at 1-kilometer intervals that provide representative coverage of nesting habitat. Going forward this design should allow us to estimate the population size with some accuracy as well as follow long-term population trends. We were able to make three flights in 2018 using this design.
Okefenokee NWR in Georgia, peninsular Florida mostly from Gainesville south to West Palm Beach, Lake Okeechobee, and the Everglades.
In Georgia small population size could result in a genetic bottleneck. Research suggests that there is little dispersal of resident birds to or from the Okefenokee NWR. A dam (The Sill) constructed in the 1950s on the west side of the Okefenokee to raise water levels and reduce the frequency and intensity of fires may cause significant long-term changes to the natural fire regime, thereby reducing the effectiveness of fire to create and maintain prairie habitat. In Florida, there are many man-made threats including collisions with vehicles and powerlines, shooting, loss of wetland and ranchland habitats, and habituation to people (e.g., from feeding) leading to negative interactions and conflicts.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Natural system modifications | Climate change & severe weather | Climate change & severe weather |
| Specific Threat | Fire & fire suppression | Droughts | Storms & flooding |
A federal species status assessment is underway to determine if the subspecies needs to be added to the federal Endangered Species List. Proposed to be added to State Protected Species List as “Rare.”
At present, the entire Georgia population of the Florida sandhill crane is restricted to the Okefenokee NWR where its habitat is protected as part of the national wildlife refuge. The Refuge’s let-burn fire policy for naturally caused (lightning strike) fires greatly increases the chances that adequate habitat will be created and maintained in the future. However, the potentially negative effects of increased water depths on prairie habitat creation and maintenance resulting from The Sill (dam) should be further researched to determine whether any actions need to be taken to mitigate any negative effects of increased water depth. Efforts to test the feasibility of establishing additional breeding sites in Georgia were undertaken in the 1980s and 1990s. The first of these efforts was at St. Catherines Island where Florida sandhill crane eggs were hatched and fostered by other crane species in captivity and released as flighted sub-adults on the island. Several of these birds reached adulthood with some successfully producing young. A few of these cranes still inhabit the island and have produced young in recent years; however, no young have made it to fledging. The second effort occurred from 1993-1995 at Grand Bay WMA where sub-adult cranes trapped in Florida were released. A few of these birds did later nest and successfully produce a few offspring at this site. However, no nesting has been observed at Grand Bay or adjacent Banks Lake NWR for many years and a 2013 survey flight failed to document any sandhill cranes at either site during the breeding season. Information collected from these efforts might prove valuable in the future if establishment of additional sub-populations in Georgia is warranted.
Abler, W. A., and S. A. Nesbitt. 2001. Translocation of Florida Sandhill Cranes to Georgia. Proceedings of the North American Crane Workshop 8:73-79.
Bennett, A. J. 1987. Movement and home range of Florida Sandhill Cranes. Journal of Wildlife Management 53:830-836.
Bennett, A. J. 1988. Habitat Use by Florida Sandhill Cranes in the Okefenokee Swamp, Georgia. Proceedings of the 1988 North American Crane Workshop.
Bennett, A. J., and L. A. Bennett. 1987. Evaluation of the Okefenokee Swamp as a Site for Developing a Nonmigratory Flock of Whooping Cranes. Georgia Cooperative Fish & Wildlife Research Unit. 111 pp.
Bennett, A. J., and L. A. Bennett. 1990. Productivity of Florida Sandhill Cranes in the Okefenokee Swamp, Georgia. Journal of Field Ornithology 61:224-231.
Bennett, A. J., and L. A. Bennett. 1990. Survival Rates and Mortality Factors of Florida Sandhill Cranes in Georgia. North American Bird Bander 15:85-88.
Dobbs, M. M. 2010. Sandhill Crane. Pages 158-159. In The Breeding Bird Atlas of Georgia. T. M. Schneider, G. Beaton, T. S. Keyes and N. A. Klaus, eds. University of Georgia Press, Athens, GA.
Florida Fish and Wildlife Conservation Commission. 2013. Florida Sandhill Crane Species Action Plan (Grus canadensis pratensis). 27 pp.
Gerber, B. D., J. F Dwyer, S. A Nesbitt, R. C. Drewien, C. D Littlefield, T. C Tacha, and P. A. Vohs. 2014. Sandhill Crane (Antigone candensis), verson 2. In: The Birds of North America (P. G. Rodewald, ed.). Cornell Lab of Ornithology, Ithaca, New York, USA.
Martin, A. C., H. S. Zim, and A. L. Nelson. 1951. American Wildlife and Plants: A Guide to Wildlife Food Habits. McGraw-Hill Book Company, Inc., New York, NY.
Nesbitt, S. A., and A. S. Wenner. 1987. Pair formation and mate fidelity in Sandhill cranes, pp. 117-122 in Proceeding of the 1985 International Crane Workshop (J. C. Lewis, Ed.). Distributed by U. S. Fish and Wildlife Service, Grand Island, NE.
Nesbitt, S. A. 1992. First reproductive success and individual productivity in Sandhill Cranes. Journal of Wildlife Management 56:573-577.
U. S. Fish and Wildlife Service. 2018. Species Status Assessment Report for the Florida sandhill crane (Antigone canadensis pratensis). U. S. Fish and Wildlife Service, Southeast Region, Jacksonville, Florida.
Walkinshaw, L. H. 1976. Sandhill cranes on and near the Kissimmee Prairie, Florida. Pp. 1-18 in J. Lewis, (ed.). Proceedings of the 1st International Crane Workshop, Baraboo, WI.
Walkinshaw, L. H. 1981. Nesting of the Florida sandhill crane in central Florida. Pp. 53-62 in J. Lewis (ed.). Proceedings of the 1981 Crane Workshop, National Audubon Society, Taveriner, FL.
Winn, B. 1990. Rearing and experimental release of sandhill cranes on St. Catherines Island. Pages 193-198 in AAZPA Annual Conference Proceedings. American Association of Zoological Parks and Aquariums, Wheeling, West Virginia, USA.
Todd Schneider
12-11-2018
