It came through the cold April air at Lynn Woods on Wednesday evening, an unexpected and welcome sound, the steady chirp of spring peepers.The diminutive frogs were crooning away within earshot of the Pennybrook Road entrance. I?ve heard them at Long Hill in Beverly, and in Western Mass, but never at Lynn Woods until last night.?As their name implies, they begin emitting their familiar sleigh-bell-like chorus right around the beginning of spring,” National Geographic reports.Perhaps it was no surprise that there were quite a few runners in the Woods that night. Spring is on the way!Maybe you thought it would never come. I remember visiting the Great Woods Road entrance about a month ago. The woods were covered in snow and ice, with the trails slippery and treacherous.At Pennybrook Road on Wednesday, there was no snow. There were, however, plenty of mud and puddles further into the woods. It is no accident that poet e.e. cummings, arguably our most famous lowercase icon after k.d. lang, described spring as “mud-luscious” and “puddle-wonderful.” On the main road, though, the surface was mostly dry and compact.Believe it or not, the Lynn Woods Summer Cross Country Races start next month. Perhaps you?re already thinking about Steel Tower and Stone Tower (the highest point in Lynn at 285 feet). The season opens on Wednesday, May 28.We?ve already had a few races here on the North Shore … the Lynn Hibernians? Recovery Run 5K last month and the Lynn Woods School Wolf Trot last weekend. And many locals are preparing to run the Boston Marathon on April 21.Yes, it still gets cold at night, and the New England spring is notorious for building up our hopes before letting us down (sound familiar, Red Sox?). However, the sound of the spring peepers tells us that warm weather is getting closer.If you run in the evening, maybe you, too, will hear the peepers. National Geographic calls them “nocturnal creatures” who frequent “wooded areas and grassy lowlands near ponds and swamps” in, among other places, the eastern US.So turn off that iPod and tune in to the enchanting sound of the spring peepers, and its promise of warmer running weather.