Animal habitats were created as far back in time as we can remember and exist in numerous places on Earth today. Over time, these habitats have undergone severe changes with human creations taking over nature. As humans, we develop and grow and as we grow so does our society. We thrive for bigger and better. But is bigger and better actually an improvement? For us, expansion seems great. Not only do the physical attributes affect nature but the noises we produce do too. Construction noise, like hammers and drills, creates loud crashes and bangs. Even once a society stands, noises that animals are unaccustomed to burden the wildlife. Comparing an audio clip from New York City and Yellowstone National park, the two are complete opposites. Soundscapes create different cultures, so they must impact animals in different ways as well. If we take a creature that has adapted to an urban environment and also lives in natural settings, we can document the reactions to sounds from both types of environments.
New York City Soundscape:
Yellowstone National Park Soundscape:
In the past, conducted experiments have monitored behaviors of animals. Some of these tests observe the foraging of animals and nesting effectiveness. The basis of most articles relates to Luo’s idea, “…anthropogenic noise represents a major environmental pollutant of global concern,” (Luo 3278). Anthropogenic noise refers to all noise created by humans and their creations. The noise aggravates the animals within the soundscape and affects their behavior. Specifically in Luo’s experiment, analysts observe animal scavenging to determine circumstances where noise pollution disrupts the animal. This link to Luo’s experiment will take you to an article detailing the experiment undergone to show a difference in foraging due to noise pollution: Luo’s Experiment
The experiment studies different cases of possible disturbance and provides analysis on results. Other experiments such as an avian habitat disturbance test addresses mating aspects and how these differ due to noise influence on the creatures, (Francis). The results to both of these came back as anthropogenic noise having negative effects. Leading me more closely to my area of interest. The differences in the animal behavior in different soundscapes.
The experiment I have conducted considers these separate conditions and compares the soundscapes of both. Squirrels are seen in multiple types of environments. Due to the multi-environment nature of them, I believe, their behavior will change with the setting. Take the urban environment of Duke Campus for example. The soundscape is all the hustle and bustle of college, similar to a city. You hear the screeching of buses coming to a halt, the chatter of students and the occasional scream of joy or laughter. With the sounds above, one cannot forget about others such as instruments near the Biddle Music Building or the many sports practices consisting of yelling, feet stomping, whistles blaring, and players shouting on the field. Take all of these elements of a populated area compared to peaceful ones. The Duke Gardens, the Duke Forest, or the Al Buehler Trail, turn the campus soundscape upside down. Out in the Forest, the sound is peaceful. There is no immediate loud talk or screeching of a cars brakes. Only consistent sounds that blend into a forest like the rustle of leaves and branches, birds chirping, and the brush of an animal moving off in the woods. These are very different soundscapes, and the animals living in both are familiarized with their settings. So how will the animals react to the noises of their environment versus the opposite? According to studies conducted, animal behavior changes with the presence of unaccustomed noises. I will take sounds from both the Duke Campus and Duke Forest and test the question.
Possible variables I have identified are noises and squirrel population. I shall take multiple sounds from the forest and campus such as buses, groups of people creating noise such as cheers at a game, construction noises, trees rustling, birds singing in the trees, and footsteps in the forest. These shall all serve as my methods of testing two separate soundscapes. By taking separate soundscapes, I hope to come to a conclusion on squirrel behavior and new noises.
The animal of choice for my experiment, as mentioned before, is squirrels. Squirrels are animals that both live in nature filled environments and also those with numerous anthropogenic noises. With the ease of access to these animals on campus, they have become ideal to use in my experiment. The squirrels should have a visible response to the types of noise being presented as pieces of two soundscapes. Since the squirrels should respond in a negative way and a way with no influence to sounds the animal is used to. I intend to evaluate the squirrel’s reaction to the noise. This will allow me to analyze how soundscapes affect squirrels and answer if animals have adapted to new soundscapes.
I began my experiment on the Al Buehler Trail. With my six recordings of individual sounds, I set out to find 3 squirrels for each. The Trail is loud but not as urbanized in the front, and once you move around the back of path, the only sounds heard are those of insects chirping, occasional rustle of leaves, and someone running by every now and then. One piece that was very noticeable were footsteps.
Footsteps alerted squirrels the most frequently. Not only was it a recording to be played, but I had to approach a squirrel without it hearing my footsteps. This took a very long time and as soon as a squirrel heard a footstep it became cautious and generally hopped along its way leaving me in need of another test subject. When my own footsteps did not scare off the squirrels this sound was played to derive a reaction:
The sounds itself also caused the squirrel to flee. This noise took longer for the squirrel to react, and still in as little as 5 seconds the animal retreated farther and farther as the noise got louder.
A noise similarly found in the forest, bird sounds, also gave quite an unprecedented response. Compared to footsteps, which may be heard less often than bird calls, bird songs caused even more disruption. Quiet bird sounds seemed to have no effect. Assuming this is because it is also possible to drown out the sound when focused on other tasks. A full minute was given to the squirrel with quiet bird calls with no result. However, when the bird sounds began or were loud an immediate reaction occurred where the squirrels jumped and started to run up a tree. The volume of the bird songs varied one was quiet while two were loud.
The final piece of nature sounds, wind in the trees, gave the most promising look at how an animal reacts to the sounds it is used to. At full volume, 3 times in a row, the squirrels look towards the source of the noise and then continue on with their business as usual.
Comparing the opposite sounds in the natural landscape produced the hypothesized results: disturbance in the animals and an attempt to evade the noise. All of these noises will not have been heard in the forest under normal circumstances, so the squirrels will more than likely be reacting to the noise for the first time.
The first sound of Duke Campus is the bus stop. A bus comes to a halt and sits before taking back off. The response time varied from squirrel to squirrel, but all eventually defaulted to a similar answer to the unfamiliar noise. On average, the squirrels took 20 seconds to flee the sound of buses. The animals stopped and looked attentively around taking note of the direction of the noise and promptly ran in the opposite direction. The squirrels took notice at the stop of the bus, and either during the hum of the bus at the stop or the vroom as the bus drove off, the squirrels retreated.
Construction, another prominent piece of the Duke Soundscape currently, created another anthropogenic noise for the experiment. Three squirrels were once again approached with a sound of major construction. This level of construction was a step above the kind happening at Duke. On the Al Buehler Trail, the squirrels waited out the noise similar to that of the bus, and then took off in the opposite direction as well. Sound evasion was a major component to the reaction of unnatural sounds.
Finally, my favorite way to test the squirrels, the use of Cameron Indoor Stadium cheers. Sound recorded from the Basketball Museum booth was recorded and taken to the forest for testing. Squirrels absolutely despised the noise. They turned and ran as soon as the noise was played.
The results of my experiment were very close to my hypothesis. The squirrels reacted to more noises than I thought they would. Only truly natural sounds such as soft bird songs and rustle of leaves in the wind saw no response in the animal behavior. The other sounds all alarmed the squirrels and caused the animal to flee. Possible ways that the data could be inconclusive would be if a squirrel had heard my footsteps before I was able to play a sound. This would have already alerted the squirrel and altered its behavior prior to the sound being played. For possible further study I would like to observe the other portion of squirrel population. Due to time constraints, an experiment on the animal population in urban environments could not be established. My results clearly show that noises foreign to a soundscape cause alarm to the wildlife, so why do some squirrels also live in majorly populated areas that contain these noises that cause them fear? I propose that animals adapt to the soundscape, and in order to demonstrate this would take on the same experiment using the same noises on squirrels running around Duke Campus. These squirrels encounter anthropogenic noises and even interact with humans on a daily basis. The relationship between the two creatures develops over time, so should the relationship with squirrels and sounds not as well? Another experiment testing this theory would shine light on the topic.
“4 Hours Natural Sounds: Morning Birds Singing (No Music)” Youtube, 4:00:00, March 19th, 2014
“Bus Stop Sound Effect | Bust Stop SFX | HD” Youtube, 0:59, July 4th, 2015
“Demolition and Construction Sounds – Over 7 Minutes” Youtube, 7:10, September 11th , 2013
“Footsteps in the Forest” Youtube, 0:32, October 13th, 2015
Francis, Clinton D., Juan Paritsis, Catherine P. Ortega, and Alexander Cruz. 2011. “Landscape Patterns of Avian Habitat use and Nest Success are Affected by Chronic Gas Well Compressor Noise.” Landscape Ecology 26 (9): 1269-1280.
Leu, Matthias, Steven E. Hanser, and Steven T. Knick. 2008. The human footprint in the west: A large-scale analysis of anthropogenic impacts. Ecological Applications 18, (5) (Jul.): 1119-39.
Luo, Jinhong, Björn M. Siemers, and Klemen Koselj. 2015. “How anthropogenic noise affects foraging,” Global Change Biology 21, (9): 3278-89.
“Rustling Leaves of the Red Oak Tree” Youtube, 4:50, October 6th, 2015
“Sounds of NYC” Youtube, 01:05:32, June 13th, 2014
“Yellowstone National Park… in HD” Youtube, 9:15, November 19th, 2009