We previously mentioned that bald eagles are coming back to the Chicago area, and now the Sun-Times reports that peregrine falcons are making a comeback, as well. The Illinois Endangered Species Board has changed the bird's classification from "endangered" to "threatened," which although it still sounds bad indicates that the falcon's numbers are on the rise. Used to nesting in cliff faces, the falcons are making their homes in any tall structure they can find: building ledges and rooftops, smokestacks, and tall trees.