In the fifty mile length of Cook County there is fully ten days difference in flowering dates between its northern and southern borders. Each spring, for thirty years, the naturalists of the Forest Preserve District have carefully recorded scores of signs of spring. Bluebirds are arriving. Duck migration is about at its peak. Crows are nesting.
Chipmunks are awake.
Cricket frogs and spring peepers are singing. Spotted salamanders are laying their jelly-like masses of eggs in still cold ponds. Painted turtles are out of hibernation and basking on sunny days. The flowers of the American elms and silver maples are wide open. The bloodroots are pushing up.