Western Chicken Turtle (Deirochelys reticularia)

Distribution: Range extends from southeastern Virginia (Mitchell and Buhlmann 1991) and eastern North Carolina south along the Atlantic Coast to southern Florida, west along the Gulf Coast to Texas, and north-ward, west of the Mississippi River, to southeastern Oklahoma and southeastern Missouri. Although present in some Atlantic coastal localities, the species is found on few barrier islands (Gibbons and Coker 1978).

Habitat: Found primarily in still waters of ponds, lakes, ditches, marshes, cypress swamps, and Carolina bays. Habitats are usually characterized as having ample aquatic vegetation and a soft bottom.

Behavior: Limited data exist for this species. Gibbons (1969) and Gibbons and Semlitsch (1981) determined that terrestrial activity is evident from March through April, and some individuals were captured entering a Carolina bay in August when other habitats dried up (Gibbons and Greene 1978). Both sexes migrate periodically between habitats, although males move greater distances than females (Gibbons 1986). The species is well-adapted to living in ephemeral habitats and coping with varying water levels (Gibbons and Greene 1990). While terrestrially active, individuals may burrow during periods of prolonged drought (Gibbons 1983). Basking is a regular daily activity, although little has been reported on the thermal ecology of the species. In the northern part of its range, the chicken turtle hibernates in mud and aquatic vegetation. In Florida it does not hibernate, but remains active except on cold days.

Reproduction: Deirochelys is one of the few North American turtle species with a "winter" nesting pattern (Jackson 1988). Although Iverson (1977) suggested that the chicken turtle nested throughout the year, no studies have been able to confirm this theory. In South Carolina, egg laying occurs in two periods: a late winter and spring period from mid-February to May, and a fall and early winter period from August to November (Gibbons and Greene 1979, 1990). In the southern part of its range (Florida), nesting may be continuous from mid-September until early March, but may be delayed temporarily by cold weather (Jackson 1988). Limited data have been published on their nesting. David (1975) described one nest as being located 50 m from the water, excavated in sandy soil, on a 15-deg slope in an area with low weeds and grass and no trees or brush within 50 m of the nest site. Clutch size in South Carolina usually ranges from 5 to 12 eggs (x = 8) (Gibbons et al. 1982) and 2 to19 eggs in Florida (x = 9) (Jackson 1988). Turtles in South Carolina lay two clutches a year, while two to four clutches are laid by Florida turtles. Eggs of South Carolina Deirochelys hatch in 152 days at 29 oC (Congdon et al. 1983), while those laid in Florida hatch in 78-89 days at temperatures from 25 to 29 oC (Iverson 1977). Some hatchlings in South Carolina overwinter in the nest (Gibbons et al. 1982). Gender determination is influenced by incubation temperature.

Food habits: During the first year of life, chicken turtles are carnivorous, but adults are probably more omnivorous. Carr (1952) observed chicken turtles eating tadpoles and crayfish. Cagle (1950) reported that chicken turtles respond best to decayed bait in traps, whereas other turtles may not enter a trap containing rotten bait. Bramble (1973) describes the feeding method of this turtle as "pharangeal" in that it captures aquatic arthropods with a well-developed hyoid apparatus, which allows it to suck in food items.

Populations: Density of up to 40 turtles per hectare has been reported for Carolina Bay in South Carolina by Iverson (1982). Sex ratios for South Carolina populations range from 1.12 to 2.79 adult males for every adult female (Gibbons 1990). Cagle and Chaney (1950) reported that chicken turtles accounted for 4.4 percent of the turtles trapped in southwestern Louisiana during 456 trap hours. Survivorship curves indicate that fewer than 10 individuals out of 1,000 live past the age of 15 years (Gibbons 1987).