turtle turtle turtle!

So yesterday on my thrice-weekly walk around the reservoir, in addition to the baby ducks, which aren't so "baby" anymore, and the little old lady who sits on the park bench and feeds the feral cat who lives in that part of the park (shhhhh, don't tell, the cat looks like a huge, cuddly Maine Coon, a lot like my sister's late cat Fritz, who was so snuggly it was a crime) I saw something I'd never seen in the park before. I've seen chipmunks, bunnies, once a tiny blind mole that was so CUTE, and of course assorted people like me who are trying to grab some nature or get rid of some pounds, and not to mention the baby carriages and couples strolling. Yesterday I saw a TURTLE! Okay, maybe not earth-shattering, but there it was. On first approach I thought it was a duck, but on closer inspection, I discovered it was definitely a turtle. Sitting half-in and half-out of the water, looking at the sky expectantly...as we all were yesterday because the sky threatened rain every minute. It had a red dot right behind its ear, and like a yellow stripe under its chin. Can anyone tell me what kind of turtle this is? I kept wondering how it got in and out of the reservoir. And how long it must take. And what it eats. Cat food maybe? I know the blue jays love "Fritz Jr.'s" leftovers...

p.s. You can always tell what time of year it is by how big the baby ducks are. Yesterday, I mistook one for a moma duck. But it was definitely a baby, exploring around on its own. They grow so fast! Okay, this amateur naturalist of Highland Park is done for the day. Maybe it's because I just finished Barbara Kingsolver's Prodigal Summer, but I feel a lot more keenly aware of the nature going on around here :)