The Carlisle Mosquito Online

Friday, July 1, 2005


Biodiversity Corner Blanding's Turtle

The Biodiversity Corner rarely reports news, but this week there is news of a rare species, the first ever confirmed sighting of Blanding's Turtle, Emydoidea blandingii, in Carlisle. The turtle is classified as "threatened," the middle group in the state's three-level system for categorizing rare species of plants and animals. Spotted turtles, which are occasionally seen in Carlisle, are in the first group called "special concern." The third and most serious group is called "endangered." In the national system for monitoring rare species, Blanding's Turtle is classified in Massachusetts as S2, meaning imperiled.

(Photo by Mitchell Weiss)

When and where seen: Nancy Weiss of Brook Street discovered the turtle in her front yard on the evening of June 26 as it was laying eggs beside an azalea bush. Nancy's find is doubly significant; first, because Blanding's Turtle is rare and second because the turtle is a breeding female. Nancy got in touch with Hyla Ecological Services, a Concord-based corporation that does a variety of ecological field research projects, including rare species surveys and habitat assessments. This was an important enough find that Dan Wells from Hyla came out on Sunday night and confirmed the identification. He is recording the find in the state database of rare species. Hyla has done a study of Blanding's Turtle population at Great Meadows National Wildlife Refuge in Concord in which five nesting females were tagged and tracked with radio transmitters. Thirty-four hatchlings were confirmed but the Blanding's Turtle population in Concord seems to be suffering a serious decline. A similar monitoring and protection project has been done in the Oxbow National Wildlife Refuge in the Harvard/Devens area.

Turtle terminology: The upper turtle shell is called a carapace; the underside shell is a plastron; both the top and bottom shells are covered with plates called scutes.

Distinguishing character-istics: Blanding's Turtle has a high-domed gray-to-black carapace, often flecked with yellow markings. The carapace of an adult is seven to ten inches long, about twice the size of the Spotted Turtle. Blanding's Turtle has a bright yellow chin and throat and a long neck. The turtle often holds its head high when basking and the yellow throat is bright enough to be seen from a distance. The plastron is yellow with large dark symmetrically arranged blotches often covering much of the scutes. The plastron is hinged towards the front which allows the turtle to completely enclose itself after retracting its head and legs. The Box Turtle has a high-domed carapace and a hinged plastron but does not have the yellow throat. The Spotted Turtle has a flatter carapace and no plastron hinge.

Life Cycle: Female Blanding's Turtles don't begin breeding until they are at least 12 years old and then only about half of them reproduce annually. The females have been known to travel as far as half a mile from their aquatic habitat to lay their eggs. Eggs are usually laid in late June in clutches of six to eleven eggs, in bare soil in warm sunny sites. The hatchlings emerge in late September or early October.

Habitat: Blanding's Turtles like densely vegetated ponds, marshes, swamps and small streams. Since these turtles may travel far to lay their eggs, we don't know where Nancy's turtle lives. Habitat destruction through development and alterations in habitat from projects like wetland drainage or road building create a threat to the future of the species.

Reporting rare turtle sightings: The Spotted Turtle, the Wood Turtle and the Box Turtle are all species of "special concern" in Massachusetts. If you see one of these, or a Blanding's Turtle, let someone know. You can submit the information yourself to the Natural Heritage and Endangered Species Program (, or let me know, or call the Conservation Commission. If possible, take photographs.

References: Leo P. Kenney and Matthew R. Burne, A Field Guide to the Animals of Vernal Pools. (I recommend this $10 book to anyone interested in wetland critters. It has lots of color photographs and includes the rare species that are sometimes left out of other field guides. (You can buy it at Town Hall.) A fact sheet from the Massachusetts Natural Heritage and Endangered Species Program at; and has an extensive compilation of observations on Blanding's Turtle from many states.

Anyone can write the Biodiversity Corner about any living thing, animal or vegetable, that exists in the wild and was seen in Carlisle. Or tell me what you've seen, or send me a photo, and I will write the column. It doesn't have to be rare. Send the information to or to Kay Fairweather, 392 School Street.

2005 The Carlisle Mosquito