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At the tail end of a bird walk in May, a friend of mine who was beating the bushes for warblers came upon an eastern box turtle. Since, unlike songbirds, box turtles can’t escape human attention by flitting away, we picked this one up to admire it. As we did, I passed along my two bits of box turtle wisdom—that males can be distinguished from females by a look at their eyes, since males have a bright red iris, and that box turtles can live to be more than 100 years old. “Really,” a fellow birder asked, “how do you know that?”
I wasn’t able to say. So I checked in with Chris Phillips, who is a herpetologist with the Illinois Natural History Survey and U of I faculty affiliate, to get my story straight. First, he pointed out that our Busey Woods box turtle was almost certainly a released pet, since there are no historical records for them in this part of Champaign County. Then he suggested that the 100-year lifespan I mentioned wouldn’t apply to wild box turtles. At the extreme, individuals in the wild may live beyond 50, but 20-30 years would probably be a more typical lifespan. Long life is the norm for turtles, and even some of the shorter lived of the species that inhabit Illinois, sliders and painted turtles, have a lifespan of 15-20 years.
Phillips pointed out that as long-lived, late maturing creatures, turtles present people who study them with distinct challenges. For example, a scientist who wants to assess the health of the box turtle population in a given area may find a whole bunch of box turtles there, and that would seem to be a good thing. But in the case of creatures that live for decades, a good head count today does not tell whether sufficient young are surviving to replace older individuals as they die.
In fact, successful recruitment of new generations seems to be very difficult for some species of turtles in the highly developed landscapes that characterize most of Illinois today. According to Phillips, scientists studying Blanding’s turtles and spotted turtles in the northeastern part of the state have found that nearly all of their eggs are eaten by other animals on the very night they are laid. The direct culprits in this case are highly adaptable, mid-sized predators--raccoons, skunks, and foxes. But it is human development that sets the stage for these particular predators to thrive as they do, at the expense of turtles and other small animals.
In addition to predators, cars currently represent the greatest threat to Illinois turtles.
[Photo: My family and I found this Gulf Coast box turtle crossing the road at St. Joseph Peninsula State Park in Florida in late March.] All turtles, including those that usually live in water, lay their eggs in nests excavated on dry land, and they sometimes travel considerable distances to reach preferred nesting sites. When their paths cross roads . . . well, turtles are not adapted to a world in which deadly threats approach at 70 miles an hour.The month of June represents the peak of turtle activity in Illinois, so be on the lookout for them as you drive. If you can help a turtle across the road without endangering yourself or other people, I would encourage you to do so. Just remember turtles will stay on course even if you try to turn them around, so move them only in the direction they are already heading.
