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Mystery Chirping Sounds

Dear Bird Folks,

Please listen to the attached audio clip. For the last few nights a bird has been chirping in our backyard, but since it’s dark outside we can never seem to find it. We even tried using the bird sound ID app, with no luck. Any clue what it is?

– Liz, Bellingham, MA


It’s not a bird, Liz,

A few weeks ago I wrote a column about the Merlin app for smartphones and how it could be used to identify bird calls. I said that the app wasn’t perfect but it was helpful in identifying the “classic” songs of many bird species. Because I ran out of room in the column (sometimes I talk too much), I wasn’t able to also mention that the app only “listens” for birds. It will totally ignore other ambient sounds such as mammals, insects or a mother calling her kids home for dinner. (I don’t think that last one even happens anymore, but it was a constant sound when I was growing up.) The voice on your audio clip belongs to a frog, a male spring peeper to be exact. I realize that it’s not spring right now, but don’t tell the peeper that. He isn’t looking forward to the coming winter any more than the rest of us are.

Many folks think of frogs as those green creatures we see sitting on lily pads or as a key member of the Muppets. But peepers are actually tiny tree frogs, spending most of their lives in the woods…except during the breeding season. Early each spring peepers leave the woods and search for vernal pools. Why vernal pools? Vernal pools typically dry up before the end of summer and thus don’t support any fish, and for a baby frog this is a good thing. A pollywog in a pond filled with hungry fish wouldn’t have a very bright future. The male peeper calls (peeps) loudly in order to attract a mate, but it’s crowded on the breeding grounds. Hundreds of competitors are also calling at the same time and from the same pool of water, and together they produce the early spring chorus a lot of us look forward to. I know I do.

Many frog species lay their eggs in a big gooey mass that reminds me of a floating glob of tapioca pudding, but a female peeper lays hundreds of single eggs. Each egg is attached to submerged vegetation, where it will only reside for a few days before hatching. In the coming months the peeper tadpole will slowly transform into a peeper frog, hoping its lungs and legs develop before the water dries up. Eventually, it will hop its way into the forest, where it won’t likely be heard or seen again until next spring. Occasionally, however, some peepers will peep in late fall. This can lead to a bit of confusion for not only you, but for a lot of other people. For example…

A chorus of spring peepers is easily recognizable, but when a single peeper performs a solo act, he actually sounds more bird-like than frog-like. One year, and on the same weekend, two different customers came in to tell me they heard “a bird chirping in the house.” It’s not unusual for a wandering peeper to end up in a garage, breezeway or even a fireplace. I explained to the first lady what was going on and even though she had her doubts, she acted as if she believed me. The second lady wanted none of it. She was insulted that I didn’t agree with her and stormed out shaking her head and mumbling rather loudly that she knew the difference between a frog and a bird. She created quite a scene, but none of my other workers even noticed. They’ve gotten used to irate customers, but more often the complaint is about squirrels and less about frogs. BTW: A week later, the first lady returned to tell me that she had found the source of the chirping and it was indeed a spring peeper. How about that! I never heard from the second lady again and can only assume she is still shaking her head and still mumbling.

While we are on the topic of mystery bird calls, here’s another sound that fools a lot of folks. Unlike the peeper, this particular sound is only heard during the day and it’s not a peep, but a loud “cluck,” as one lady described it. She was certain that a turkey was clucking in the nearby bushes, but she could never find it. These mysterious chips, aka, cluck sounds, invariably turn out to be our old pal, the Eastern Chipmunk. Chipmunks are so named because they’ll often sit and give a long and surprisingly loud series of monotonous chips. Having learned my lesson from the lady in the previous paragraph, I now show people actual videos of chipmunks producing these mysterious calls. It puts an end to the head shaking and mumbling. FYI: More often than not it is women who ask about these odd calls. I rarely get these questions from men. It’s not that the men don’t hear the weird sounds, but instead of asking me about them, they just turn the TV up louder.

The officials aren’t sure why some peepers begin peeping in the fall, Liz, but one theory suggests the little frogs are fooled when autumn conditions mimic those of the spring. Whatever the reason, they don’t peep for very long and soon they get ready to hibernate for the winter. But the people who make the Merlin app won’t be hibernating. Rumor has it that they are working hard to upgrade their sound ID to also include insects, amphibians and other sounds of nature. Speaking of nature sounds, I just heard my wife calling me. It’s not dinnertime, so she must have a chore for me to do. I probably should answer her, but nah. I think I’ll just turn the TV up louder.