The city's chokecherries are shading from red to nearly black, and that's ripeness. Too astringent to enjoy raw (the name is honest), they're the classic prairie syrup-and-jelly fruit, and for robins and waxwings they're the feast of late summer. Watch a heavily loaded tree for ten minutes and count the visitors. If you pick, take only the flesh; the pits and leaves aren't safe to eat.