For a long time, I've wondered why there aren't any squirrels in my neighborhood, although we have plenty of trees. We often see bunnies, but for squirrels I have to walk to the lakefront.
Last week I was reading an Audubon Society newsletter, and one of the articles referred to a local wildlife biologist, Joel Brown. So I wrote to him. A few days later, he wrote back. Squirrels don't just need trees, he pointed out, they need nut-bearing trees. Oaks, walnuts, hickories. And/or accessible feeders in yards full of stuff they like to eat.
The streets around here are lined with mostly ornamental, flowering trees: crabapple, Eastern redbud, cherry. No oaks. And with so many multi-unit buildings, there aren't many feeders in the area.
Mystery solved. Thank you, Dr. Brown!