What the robin is to lawn and meadow, the peeper is to the wooded swamp. The first robin usually appears on a bright, though still chilly day, hopping over a bit of dry yellow grass revealed by the retreating snow. The peeper comes to us as a distant chorus on the first evening a light coat or sweatshirt will suffice, or all of a sudden when, on a night warm enough to crack a car window, we pass a bit of low ground flooded by the spring rains and snowmelt. They’re more often heard than seen. Approach them, and the song cuts off well before you can get near. Peepers are skittish. You would be too if you were very small and made a sound that could be heard a mile away. Nevertheless, they have some remarkable abilities.