SREL Reprint #3154

Orientation and dispersal of hatchling Blanding's turtles (Emydoidea blandingii) from experimental nests

M. J. Pappas1, J. D. Congdon2, B. J. Brecke3, and J. D. Capps4

1Michaels Restaurant, 15 South Broadway, Rochester, MN 55904, USA
2Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
322675 Co. Boulvard 18 No. 58-A, Welch, MN 55089, USA
4Allterra Environmental Inc., 207-B McPherson Street, Santa Cruz, CA 95060, USA

Abstract: We determined initial dispersal directions of 1052 naïve and 278 experienced hatchling Blanding's turtles (Emydoidea blandingii (Holbrook, 1838)) in experimental arenas in a variety of settings. Dispersal of naïve hatchlings was nonrandom in 7 of 10 sites. All nonrandom dispersal patterns suggested hatchlings primarily used vision to orient toward dark far horizons, particularly those associated with riparian habitats. We found no evidence that hatchlings use positive geotaxis, olfaction, humidity gradients, or scent trailing of other individuals during dispersal. Despite the lack of relationships between the changing position of the sun and relationships between nest sites and wetlands, patterns of dispersal were different for hatchlings released in the morning and late afternoon at two sites. Comparisons of the dispersal of naïve and translocated experienced hatchlings (those with previous exposure to environmental cues) suggest that hatchlings develop a sun compass within 2 days of emergence from nests. Based on all nonrandom dispersals of hatchlings at arenas, the estimated maximum perception distance of hatchlings was 325 m. In some situations, forest succession, agriculture activities, and introduction of pine trees may increase risks faced by hatchlings dispersing from nests by reducing their ability to find wetlands.

SREL Reprint #3154

Pappas, M. J., J. D. Congdon, B. J. Brecke, and J. D. Capps. 2009. Orientation and dispersal of hatchling Blanding's turtles (Emydoidea blandingii) from experimental nests. Canadian Journal of Zoology 87(2009): 755-766.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).