Blanding's Turtle Fact Sheet
New York Status: Threatened
Federal Status: Not Listed
The Blanding's turtle is a medium sized turtle with an average shell length of approximately seven to nine inches and a maximum length of 10 inches. A distinguishing feature of this turtle is the bright yellow chin and throat. The carapace, or upper shell, is domed, but slightly flattened along the midline, and is oblong when viewed from above. The carapace is speckled with numerous yellow or light-colored flecks or streaks on a dark background. The plastron, or lower shell, is yellow with dark blotches symmetrically arranged. The head and legs are dark, and usually speckled or mottled with yellow. The Blanding's turtle is also called the "semi-box" turtle, for although the plastron is hinged, the plastral lobes do not shut as tight as the box turtle's.
Mating probably occurs in April and early May with nesting beginning in early June and lasting throughout the month. The clutch size varies from region to region. In New York, the clutch size ranges from 5-12 eggs with an average of eight. The Blanding's is a timid turtle and may plunge into water and remain on the bottom for hours when alarmed. If away from water, the turtle will close itself up within its shell. It is very gentle and rarely attempts to bite. It is very agile and a good swimmer.
The Blanding's turtle overwinters under or near water, in mud or under vegetation or debris. During the nesting season, a female Blanding's turtle may be found more than a kilometer from where it hibernated. It is omnivorous, eating crustaceans and other invertebrates, fish, plants, carrion and vegetable debris. It is capable of catching live fish. Blanding's turtles take 18-22 years to reach sexual maturity and may live to be 70 years old.
Distribution and Habitat
This species' range centers around the Great Lakes, and extends from central Nebraska and Minnesota eastward through southern Ontario and the south shore of Lake Erie as far east as northern New York, with a few disjunct populations in southeastern New York (Dutchess County), New England and Nova Scotia. Recent investigations in northern New York report the range of this turtle to be primarily in the vicinity of the Thousand Island region along the St. Lawrence River. In this region it is found in isolated coves and weedy bays, and further inland in shallow, marshy waters and ponds. It does not commonly occur in the main channel of rivers.
A major problem facing the Blanding's turtle in New York State is the destruction of its habitat through the construction of housing developments, shoreline property and other summer recreation facilities. Roads which cross migration routes between the ponds where the turtles hibernate and the areas where they nest are particularly hazardous to the species.
Management and Research Needs
Field surveys to more accurately define the range of this species in New York and to estimate the size of populations are being conducted. Mark/recapture and radio telemetry techniques are being used to further define daily and seasonal movements, habitat utilization, and nest selection. Experimental nesting areas are being created in order to minimize hazards associated with long distance nesting migration. Newly hatched turtles are being head-started for release back into the wild to enhance declining populations.
Babcock, H. L. 1971. Turtles of the Northeastern United States. Dover Publications, Inc., NY
Carr, A. 1962. Handbook of Turtles. Cornell Univ. Press, Ithaca, NY.
Conant, R. and J. T. Collins. 1998. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Third Edition Expanded. Houghton Mifflin Co., Boston.
Congdon, J. D. 1993. Delayed Sexual Maturity and Demographics of Blanding's Turtles (Emydoidea blandingii): Implications for Conservation and Management of Long-Lived Organisms. Conservation Biology Vol. 7 No. 4.
Ernst, C. H., J. E. Lovich and R. W. Barbour 1994. Turtles of the United States and Canada. Smithsonian Institution Press, Washington and London.
Harding, J. H. 1997. Amphibians and Reptiles of the Great Lakes Region. The University of Michigan Press, Ann Arbor. 378 pp.
Vogt, R. C. 1981. Natural History of Amphibians and Reptiles in Wisconsin. The Milwaukee Public Museum, Milwaukee, Wisconsin.
Map adapted from Conant and Collins (1998),Ernst, Lovich and Barbour (1994) and Harding (1997)