We were having dinner out the other night and overheard a woman in the booth next to us remark that she didn’t have a recipe for squirrel pie. For some people squirrels are food, for others they’re a pest. For us, squirrels are for entertainment and nature study.

Squirrel expert Ben Dantzer, a U-M assistant professor of ecology and evolutionary biology, says that because squirrels don’t dig up all the nuts and seeds they bury, they help to reforest our woods–he calls them “smaller, furrier Johnny Appleseeds who are not stringent in what they are willing to plant.” They’re also important, he says, in human culture, because people have good stories to tell about them.

There are four species of tree-dwelling squirrels in the area, but the ones we see most regularly are fox squirrels and eastern gray squirrels. Fox squirrels are the largest of the bunch and, according to Dantzer, the ones most comfortable in an urban environment.

Gray squirrels are smaller and more suburban in their likes, preferring stands of mature hardwoods. That said, there is some variability in chosen habitats and whether one sees more of one than the other of these two is very localized.

The two species differ not only in size, but in coloration. In our images, the fox squirrel standing on its hind legs in the grass has a blond underside. The squirrel eating off the ground is also a fox. The remaining two photos are of gray squirrels. Their undersides are typically white, but there are lots of color variations, the most striking of which is an all black phase: “black squirrels” are gray squirrels.

Another identifier are the ears. Grays have large ears which stick out. Foxes’ ears are closer to the head.

Squirrels of both species have home ranges. And both raise their young in trees, either in cavities or large, haphazard-looking nests made of leafy twigs.

See one fox or gray squirrel running after another? It may be a male pursuing a female. Sometimes an entire group of males is doing the chasing. Though more than one dad may contribute to the creation of a litter, they do not help raise the offspring.

Red-tailed hawks are the biggest predator of squirrels locally. Dantzer once saw a red-tail on the Diag, dining on a fox squirrel which it had hunted there. Human kills due to hunting and automobile collisions contribute to the mortality rate.

Though less commonly seen, red squirrels and flying squirrels also have substantial presences here. According to county parks naturalist Shawn Severance, red squirrels moved into County Farm Park about six years ago. Reds are smaller than fox squirrels, but are louder and pushier and now occupy territory formerly the domain of fox squirrels. Although they are often thought of as forest dwellers, some of them hang around the park’s playground area, taking advantage of the cavities in the mature trees there.

Flying squirrels, which are smaller still, are less uncommon than people think, says Severance. She says they may be found in the trees up and down along the Huron River. However, to see them one would have to be a night owl–joining any real owls who might be out hunting these nocturnal creatures.