School's in session for turtle tracker

School's in session for turtle tracker

CHICAGO SUN-TIMES (Illinois) 21 July 05 School's in session for turtle tracker (Gary Wisby)
Unlike most turtles, the Blanding's turtle has a hinged bottom shell section that swings shut to protect its head and front feet from predators.
It's also shy and nervous, quick -- for a turtle -- to dive into the water if danger appears. And it can stay on the bottom for half an hour if it has to.
Even so, the Blanding's turtle is on the decline in the Chicago area and threatened in Illinois. To help find out why, Mike Dreslik is gluing radio transmitters on a population of the turtles in a Will County marsh so he can follow them around.
Dreslik is a newly minted University of Illinois Ph.D., who is just starting work as a scientist for the Illinois Natural History Survey. This summer and next he is tracking 40 Blanding's turtles, mostly female, including six juveniles.
He'll see what kind of habitat they like, how much ground they cover, where females nest, how many of their hatchlings survive raids by raccoons and even how many of them end up as roadkill. His findings will help show land managers how to preserve or enhance habitat to give the turtles a better chance.
The transmitters, weighing 20 ounces or less, are glued on the rear of the turtles' shells and off to one side.
"It's like carrying a backpack," Dreslik said. "It gives us a wonderful view of the organism that's extremely difficult to get any other way."
Named for William Blanding, the Philadelphia naturalist who first described it in the early 1880s, the reptile has a bright yellow throat and a smooth, helmet-like top shell that usually is black speckled with yellow.
To lay her eggs, the female leaves the water and travels up to 1,000 yards until she finds a spot that's not too shady, so the sun can act as an incubator. Then, having filled her bladder before she left, she releases into the soil to soften it up for digging. After laying her eggs in the hole, she covers them and leaves.
At this point, raccoons are the biggest threat. "They're phenomenal at finding turtle nests," Dreslik said.
A study in Michigan found one turtle habitat where raccoons devoured every egg. Even when eggs are untouched, hatchlings -- little more than an inch long -- must make their way to water by the same route as their mother.
Those hardships, along with habitat destruction, water pollution and auto traffic, make survival a challenge. But the Blanding's have a defense -- longevity. Many of them are still reproducing at upwards of 70 years old.
"I think they've outlived many of the researchers," Dreslik said. "If you're doing long-term studies, you're going to have to put them in your will so someone else can carry the torch after you're gone."
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