As Late Summer begins, all the katydids sing after sundown. They call out the close of the Dog Days, and even though heat often lingers, the rhythm of the season has shifted, its tones have been altered, colors and sounds and scents all pointing to fall. Migration clucking among the robins increases. Some days, there is a long and steady cardinal song before sunrise, then silence. Hummingbirds, wood ducks, Baltimore orioles and purple martins start to disappear south; their departure marks a