We live in a noisy world. With earbuds and surround-sound systems, we have more than enough opportunities to plug in. From mechanical rumbles in cities to whispering winds in the wild, sounds envelop us. But which ones should we—or any other creature—pay attention to? How do we filter the vibrations to discover what we want or need to know? How reliable is our selective hearing? What really is music to one's ears?

In "Squeaks and Whistles, Grunts and Hums" in this issue, Mary Hoff offers a primer on wild noisemakers. Focusing on a few exemplary critters—owl, coyote, toad, fish, beaver, spider, cicada, and woodpecker—the story tells how, when, and why they make noise. Wild ones listen intently too, because their lives depend on audible messages as they hunt for food, steer clear of danger, and find each other.

"Birds and mammals live embedded in an acoustic network, each individual connected to others through sound," writes David George Haskell in The Forest Unseen. Vibrant natural soundscapes include us humans. We just have to tune in.

In "A New Chapter for Elk," Joe Albert and his companions go to northwestern Minnesota hoping not only to see wild elk but also "to hear a bull elk's haunting bugle." Michael Furtman's "Have You Seen a Grosbeak?" could just as well ask if you've heard one. Before he spots a pine grosbeak one winter day, the author tunes in to soft, sweet songs and "lilting conversations." Likewise, he says, in spring you're more likely to first notice the melodious song of a rose-breasted grosbeak and then observe this bright singer.

If you want a longer lesson in listening to birds, consider studying Donald Kroodsma's Birdsong by the Seasons. He recommends first listening to the accompanying CDs and then reading the book. He presents sonograms for visualizing bird vocalizations as you listen. Beginning with pileated woodpeckers in January, he walks you through his meticulous field-recording sessions. On New Year's Eve, he sets up his recorder and parabolic microphone, poised to capture the call of a young female pileated as she returns to her roosting cavity. He notes ambient sounds such as whistles of starlings and the Amtrak train. Then, in "the brief lull that followed the train," he says, "I first hear her, calling in flight, a wild kuk-kuk-kuk-kuk-kuk-kuk-kuk, seven or eight a second, and I then see her, too, in undulating flight, coming right toward me." In the morning he returns to wait for her to emerge from the tree. At the end of his minute-by-minute account, as she flies away just before sunrise, he writes: "Her only sounds have been those of her feet, her wings, and her bill. Not a peep did she utter as she greeted the new year."

This issue includes a profile of Bohemian waxwings. Like cedar waxwings, they are songbirds without a song. During breeding season, cedar waxwings are "remarkably quiet," Kroodsma writes in his book. Instead of singing, males and females make "bzeee and see notes," he says. "Oh, how I would love to know what each little twist and turn of these notes means to the birds."

Don Schreiner's "A Superior Success Story" illustrates other ways of tuning in and discerning what matters. The Lake Superior lake trout fishery collapsed in the 1950s due to overfishing and invasion of parasitic sea lampreys. Schreiner and other fisheries biologists set to work studying the situation, testing solutions, and evaluating results. They targeted lamprey with chemicals, stocked trout, enlisted commercial netters to assess fish populations, surveyed sport anglers, and listened to locals with firsthand experience. Schreiner welcomed the insights of a longtime commercial fisherman who became his friend and mentor. But when his friend said the lake trout fishery would never thrive again, Schreiner relied instead on the scientific evidence, the data, and held out hope.

Rehabilitation takes a long time—in this case, more than 50 years. Schreiner's friend did not live to see the lake trout fishery rebound. Today's news of recovery really would have been music to his ears.