The Music of Monteverde

By Anna Wassel

As a plant person, I use the senses of touch, smell, sight, and, occasionally when I’m sure it’s safe, taste to identify or enjoy a plant out in nature.  Listening is not so common for me.  I never put too much thought into the various chirps and trills and clicks I heard in the forest.  After a week in the cloud forest of Monteverde, located in the Guanacaste province of Costa Rica, I learned to experience the forest in a whole new way. Apparently, just as humans have different tones of voice to convey different feelings, animals, too, convey different messages with different pitches and sounds. 

I knew some people are very interested in learning bird calls, but didn’t know that one bird could have so many calls (except for birds like Mockingbirds, that I knew copied other sounds heard in the forest).  Apparently, many people didn’t know that birds have what are called “soft calls” until relatively recently, starting in 1998.  A soft call is a call that is much quieter than a typical call, and sometimes have much more complicated notes.  They can be used to call out to nearby females without alerting predators or competing males of the location of the birds.  They have also been described in crickets and bats, as well! I imagine it’s the equivalent of a high school boy climbing up to his girlfriend’s window and whispering to her to come closer to open the window without letting her parents hear. 

We also learned about the different calls of frogs, and all their different kinds of calls.  There are different tones for announcing to all the lovely, eligible frog-ladies out there, where the attractive males can be found, and again, like the birds, tones for whispering to closer ladies to come a little closer, and other tones to express aggression, frustration, and fear.  There are frogs that sound like cows and others that sound like sheep while trying to attract a mate, while the Smoky Mountain Jungle frog has a call for when predators grab it in hopes of startling or scaring the predator that essentially sounds like it is screaming, “Ow!  Ow!  Ow!”

          Armed with this newfound knowledge, I got a whole new appreciation for our hikes.  The loud, flamboyant, complex call of the Oropendula bird, known for its pretty golden tail, and hanging nests, really struck a chord with me like no other bird call had in the past.  Now, when I heard a bird in the forest, I could think about whether it was their simple song, or a more complex whisper.  I could differentiate layers of sounds beyond the ominous call of the howler monkeys that like to wake us up a bit too early for my tastes.  There were cicadas, there were bird calls, and bird whispers, there were the chirping and scampering of foraging coatis early in the morning, there were a few frogs at night, trying not to get eaten in the dangerous moonlight.  It was like someone upgraded a movie ticket to my favorite movie from standard to 3D; there were new levels of sound that I had never recognized. 
             Surprisingly, many acoustic questions have not been answered in science since recording equipment just became affordable and transportable recently.  While I still love my quiet little plants, I am excited to learn more about the voice of the forest in the future.