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An Eastern Mud Turtle's carapace (i.e., top shell, above left) is quite smooth with very little evidence of growth rings; it is unmarked and somewhat light-colored, although individuals show a great deal of variation from tan to olive to dark brown. There is a double-hinge about a third of the way back on the plastron (bottom shell, above right) that allows the shell to close partway. The plastron can be yellow or brown but in our experience is most often some shade of red--especially bright in hatchlings. This hinged, reddish plastron gives rise to the Eastern Mud Turtle's scientific name of Kinosternon subrubrum, from Greek and Latin words for "moveable chest" and "red beneath." Fairly recently (about 1990), another species--the Striped Mud Turtle, Kinosternon baurii--was documented in North Carolina's Coastal Plain. It usually has three longitudinal stripes on its carapace and a pale head stripe that extends from the nostril through the eye; these markings are very different from the Eastern Mud Turtle's plain carapace and reticulated head.

A side view (above) shows the Eastern Mud Turtle's carapace is taller in back, which always reminds us of the PT Cruiser--Chrysler's popular retro automobile. (Despite the physical resemblance, we assume the car's acceleration speed is far greater than that of the turtle.) The photo above also reveals that both the anterior and posterior ends of the plastron can flex, thanks to the cartilaginous hinge absent in most other aquatic turtles. Some authorities report that mud turtles give off a distinctive musky aroma, but the one we encountered this week was essentially odorless--nothing like its similarly sized and extremely pungent relative, the Eastern Musk Turtle, Sternotherus odoratus.

Sexing Eastern Mud Turtles isn't always 100% accurate, but we're pretty confident the individual illustrated here was a male, based on his thick tail tipped with a small spine--plus a concave plastron (above) that enhances his ability to slide onto the female's carapace during copulation. By comparison, the female's plastron is flat or with a slight outward bulge--all the better to provide room for internal development of eggs. Several weeks after mating--which typically happens underwater in late spring--the female mud turtle leaves her pond or stream to find a suitable nesting place. There she first uses her forelegs to excavate a shallow semicircular depression that she deepens with her hind limbs before laying relatively few eggs--typically one to five--and then may or may not cover them with soil or vegetation. The eggs, about half an inch wide by an inch long, have a harder shell than that of most turtles and do not absorb much moisture. Although some Carolinas mud turtlets may break out of the egg and move toward ponds in late summer or early fall, it appears that many hatch and then overwinter in the nest before emerging the following spring. Up to three clutches per female per year have been documented in the South.

One quizzical thing about the Eastern Mud Turtle we recently came across at the Center was the condition of his carapace. The back left quadrant was scarred with indentations (above) that we suspect came from the teeth of a carnivore--probably a domesticated dog that found the wandering reptile one day and played with it a while before losing interest. If that was the case, our slow-moving friend fared better than some of his conspecifics eaten by River Otter, Raccoon, or--when they were still turtlets--a water snake or other predator big enough to swallow them whole. Car and truck tires kill many more adult turtles--particularly females as they seek nesting sites--and draining wetlands takes significant toll. So far, sufficient numbers of Eastern Mud Turtles avoid such difficulties, live several decades, and carry on the species--which we hope is the future of the one we photographed and returned this week to the muddy, murky bottom of Hilton Pond.

Be sure to scroll down for an account of all birds banded or recaptured during the week, plus other nature notes of interest.

--It would appear that the bulk of spring songbird migration is over at Hilton Pond Center. The paucity of birds--plus two days of substantial precipitation (1.4" on 19-20 May) and an out-of-town trip--resulted in very few new bandings or recaptures. Seldom do we see a Ruby-throated Hummingbird these days.

--We were privileged this week to speak in Asheville to the annual gathering of the North Awerican Bluebird Society. Hosted this year by the North Carolina Bluebird Society, the four-day meeting drew participants from across the U.S. and Canada. North Carolina's chapter is especially strong, but we've been unable to generate enough interest to establish a similar group in the Palmetto State.

All text & photos © Hilton Pond Center