How Human Noise Pollution Affects Birds In The Valley

May 24, 2021

A Gray Catbird In The Shenandoah Valley
Credit Tibbett Speer

With spring bird migration in full force in the Shenandoah Valley, WMRA’s Chris Boros spoke with Dana Moseley, a JMU professor who studies birds that make the valley their home and the human noise pollution that affects their feathered lives.

Dana Moseley:  This is a pretty new pressure that birds are facing since our Industrial Revolution.  Birds have been communicating for hundreds of years with natural noises like wind or other species of birds, cicadas. But this noise that we produce through traffic or industry, construction, that's pretty low frequency noise. So parts of the bird’s songs that are also low pitched are being overlapped and masked. And that really causes a problem for birds because they use their song especially to attract mates. So, there song in a sense is a direct link to their ability to reproduce successfully.

WMRA:  Is it too simple to suggest that they are in a sense competing with us?

DM:  Absolutely. If you think about sound, they're competing for space in sound waves at different pitches.  Some species of birds have been shown to sing at higher pitches in noisy areas and in part this is correlation we find that if you compare the same species in a quiet rural habitat, they're singing much lower than their urban counterparts.  So with the white crown sparrows that I've studied with colleagues, we've seen that in one generation baby birds have learned higher-pitched songs rather than lower pitch songs, when they've been raised in noise that overlaps those songs.

WMRA:  Is it only the songs that are affected or is it also their migration or even breeding habits that are changing because of noise that we make?

DM:  That's a big open question. So some of the correlative studies have found that in the noisiest places, certain species just don't occur.  So something about the noise is predicting that those species that sing really low are just not even going to occur.

WMRA:  How do you go about researching all of this? I'm assuming you're in the field a lot studying birds in nature.

Dana Moseley Recording Bird Songs
Credit Tristan Spinski

DM:  When you study urbanization, you get to travel a lot around your local area. We research birds right around here at the Arboretum at James Madison. And we go to a local Farm owned by Bib and Dolly Frazier, a beautiful site that's being restored and has great habitat for birds all the way to the national forest. And we have a lot of sites around DC.   So we're looking at an urban gradient because if the question is how does noise or urbanization affect the breeding behavior and communication, you need to study these birds at various levels of urbanization.  We start in April, so we're out in the field now looking at the returns of some of these migratory bird species just arriving setting up their territories. The males are singing their heads off and trying to defend that, establish it and attract females who tend to take their time and coming back from migration to save energy for the breeding season.

WMRA:  Is there a specific bird species that you study that you can tell us about?  Throughout all of your research, is there one in particular species that you like to study and why?

DM:  We are researching the gray catbird.  They have a lot of different sounds that they make.  Part of their song includes mimicking other species sounds but they also invent things and make their own cat birdy sounds which actually sounds like a cat.  We're studying them is because you can find them across a lot of levels of urbanization as opposed to species that either just don't occur in the middle of a city or don't occur in a really less impacted habitat like the national forest.

Dana Moseley In Her Natural Habitat
Credit Tristan Spinski

WMRA:  So why birds were you Dana? Is there something you've always been interested in when you were a kid?  Were you into birds and nature?  How did you choose this profession?

DM:  I've always been interested in nature growing up in a rural part of North Carolina and playing in the creek and certainly being influenced by my mom, who’s a retired professor from Guilford College. So she really inspired me to have a love of birds, but I had a rebellious period studying salamanders. So after a trip to Peru with my undergraduate advisor, I really fell in love with the communication ability of birds that they're spending a lot of their time singing.  And I've always been curious about what they're saying and why and how.