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In the midday heat of a lazy, summer day, I poke along the shoreline of a small central Wisconsin lake. Watching swooping tree swallows, darting dragonflies and basking painted turtles, a splash of yellow catches my eye. I discover a Blanding's turtle resting in the green duckweed soup – an individual only detected by its bright yellow chin and throat sticking above the water line.
The Blanding's are timid turtles, quick to retreat and disappear. The six- to ten-inch turtles inhabit ponds, small lakes, marshes or some northern bogs. No other turtles have such bright colored chins and throats. Their heads are rather flat with a short, rounded snout, and the upper jaw is notched in the front so the turtles appear to be smiling. The top side of their head, long neck, legs, tail and smooth upper shell (carapace) are blue-black spotted with yellow flecks, a color pattern that blends in perfectly with dark water, floating vegetation and shadows.
Blanding's turtles don't spend all the time in their chosen ponds. They forage in adjacent grassy marshes and wet meadows. Since they spend time out of the water for reasons other than nesting, they are called semi-aquatic turtles. On land, another prominent feature the domed carapace, resembles a World War I soldier's helmet. The bottom shell or plastron is yellow, marked with dark brown blotches along its margins. It's hinged across the upper third and if the turtles are threatened, they pull in their head, feet and tail, compressing the plastron for protection.
Blanding's turtles (Emydoidea blandingii) spend a good six to seven months of their year hibernating in pond bottom mud. They are fairly tolerant of cold temperatures and may emerge from winter's inactivity as early as April. Mating occurs in the water in spring. Females begin nesting in June, leaving the safety of their pond to travel overland as far as a half-mile to find a sunny nesting site in moist, well-drained soil. The turtles are vulnerable during this overland trek as they often cross highways. After choosing the perfect site, the females dig holes and deposit from 6 to 17 elliptical white eggs, each averaging 1.4 inches in length. After covering the nest, females leave.
If the sun-warmed nests are not destroyed by hungry skunks and raccoons, turtles hatch in 50 to 75 days from August into October. The temperature during incubation determines the sex of the 1.3-inch-long hatchlings. Eggs incubated at 25°C (77°F) or lower become males, while those exposed to higher temperatures become females.
The young turtles make their own perilous journey back to water, then they seemingly disappear. Very little is known about their young lives until they attain a length of about six inches. Once they are large enough to be safe from predators, we see them basking in the sun.
Blanding's turtles are long-lived and 14 to 20 years pass before they reach sexual maturity. Even then, only about half of the females nest each year. Old turtles may be 50 to 75 years old and still capable of reproducing.
Blanding's turtles feed on snails, crayfish, small fish, tadpoles, frogs, insects, earthworms, slugs and anything else that slow-moving reptiles can catch. On land, they may consume plants, berries and grasses.
Wisconsin is nearly in the center of their Great Lakes distribution. Here, and throughout much of their range, they are listed as a threatened species. Though recent surveys suggest the Blanding's turtles are becoming more numerous, human activities causing wetland loss, habitat fragmentation and road development take their toll.
In my own slow meanderings, I have crossed paths with several Blanding's turtles. Each encounter has been memorable and I always give the turtles the right of way and watch them. I'm entranced by their beguiling, infectious "smile," and I can't help but return it.
Don't let her kid you. The sure-footed, quick-paced Anita Carpenter walks and watches wildlife near her Oshkosh home.