Among the many ways we are transforming the planet and its habitats for other species, one that is only now receiving some attention is that of sensory pollution. This is when we pollute the environment in such ways as to interfere with the sensory perception and communication systems of animals – i.e., dull their senses in potentially important ways. While much attention has been paid—and justly so, ever since Rachel Carson’s clarion call—to the wide variety of chemical pollutants we’ve introduced into habitats all over the world, we haven’t really paid much attention to the sensory effluvia that come in the wake of modern civilization. Two common ways we mess up the sensory systems of animals are by interfering with the visual and auditory channels of communication: e.g., increasing turbidity in water makes it difficult for fish to see and communicate with each other using visual signals (color patterns, changes to and movements thereof); increasing noise from our cacophonous machinery on land and in water makes it difficult for animals to talk to each other. We are a flashy, noisy, brash, uncouth, species indeed! No consideration for the sensibilities of our planet-mates…
But that may be changing. Sensory pollution is getting increasing attention from biologists in recent years, as exemplified by a symposium on the topic at Behavior 2011, the joint meeting of the Animal Behavior Society and the International Ethological Conference, being held at Indiana University this week. I wish I had been able to attend, especially for this symposium, because I’ve been thinking about and trying to study the effects of urban noise on bird song and behavior for some years now. Although I couldn’t travel to the meeting, I’m happy that my lab was well represented – see below!
After co-authoring the first comprehensive review of urban bioacoustics (i.e., the study of how animals use sound; in cities), then moving to Fresno with this job, actually measuring the effects in wild birds, and testing some of the theoretical ideas outlined in our review was one of my first priorities. Easier said than done, though – especially for a naive faculty member coming to grips with the nature of teaching and the student body at an institution like CSU-Fresno! Between my increasingly heavy and chaotic teaching load, and several unreliable graduate students, it became rather a stop-start project – more stop than start for several years. That all changed a year ago, however, when two eager new graduate students entered my lab, already interested in birdsong and very keen to tackle the subject of urban noise. Over the past year, Jenny Phillips and Pedro Garcia have been studying the effects of noise on the songs of two species (seen above) that occur in urban and rural areas around here: the White-crowned Sparrow, winter visitor to the valley from northern breeding grounds, and the House Finch, year round resident in these parts. An interesting opportunity to compare what noise pollution does to the songs and singing behavior of two rather different species: one migratory, the other sedentary, one singing to claim territory and warn competitors, the other warbling in the spring to attract mates!
Today, Jenny and Pedro presented the first results from their research as a poster at Behavior 2011. Having helped them analyze their data and design the poster over the past few days, I’ve been something of an anxious parent this week, wondering how they are doing out there on their own, even as I followed the #behav11 hashtag on twitter to see what I was missing! A short while ago, a tweet (of course) informed me that “…they did a gr8 job!!” Phew! Not that I expected anything less…
If you, like me, missed the whole meeting, allow me to share their poster here, starting with this abstract:
EFFECTS OF URBAN NOISE ON SONG STRUCTURE IN A SEDENTARY AND A MIGRATORY BIRD SPECIES
Jenny Phillips, Pedro Garcia, Lauryn Moles & Madhusudan Katti
California State University, Fresno, United States
Many animal species are dependent upon vocal communication to mate and defend territories. Selection will favor individuals that produce vocalizations that transmit best in their environments. The sensory drive concept suggests that environmental conditions, such as ambient sound, will influence the evolution of vocal behavior. Thus, background noise levels may have a profound effect on communication. We study how urban noise affects the cultural evolution of birdsong in two species: the migratory white-crowned sparrow (Zonotrichia leucophrys gambelii) and the sedentary house finch (Carpodacus mexicanus). These two species are ideal study organisms because they each have one song type, are territorial, and are easy to identify. We recorded songs and ambient noise concurrently across the Fresno-Clovis Metropolitan Area (FCMA) and in outlying rural areas for comparative analysis of acoustic properties, in particular the frequency and temporal structure of songs. Because song influences fitness via phenotypic and genotypic mate quality, understanding how song changes in an urban environment may allow us to predict species adaptability in a changing world.
And here is the full poster – leave a comment if you have any thoughts on this ongoing study: