While at CERA, we examined the sounds in three locations within the oak savanna. In the first location we were surrounded by oak and shagbark hickory trees and plant life that was not very diverse. Roughly half of the sky was covered by oak branches in this area. We heard many sounds in this first area, including the calls of various insects including, crickets and cicadas, each of different lengths and speeds; both long and short bird calls coming from every direction; vehicles driving along the interstate creating a deep whining sound almost like a strong wind. The sound in this area was lower pitched than it was in the other areas.

While at CERA, we examined the sounds in several different locations within the oak savanna. This particular audio file was taken at the edge of the savanna, where there were fewer trees and more diverse plant life than in the center of the savanna. Compared to the center of the savanna, the whine coming from the interstate was louder and higher pitched; bird calls were louder, making the birds seem as if they were closer to us, and making it easier to identify that not only were the calls were in response to one another, but each type of bird had its own unique call; there were the constant chirps coming from cicadas and chirps coming from other insects; and the wind was more noticeable as it ran through the plants and tree leaves surrounding us.

We recorded with the microphone held aloft on the northern shore of the east-west running section of CERA’s creek. This was specifically recorded as the wind was picking up and leaves from the nearby trees were being blown off – the height of the recording was intended to capture that sound. We cannot remember which direction the wind was blowing.

As with the rest of the creek area, the most noticeable sond was that of the insects. One type of insect simply filled the air with a continuous, unchanging noise in a 4 – 6 kHz band, while the other insect (possibly alone) produced a repeated staccato phrase that sped up and increased in volume significantly before stopping. The sound that promped this particular recording was the falling of leaves due to the wind. Therefore, the recording begins with this sound in full force, though it is quiet, and throughout the course of the first 20 seconds, the sound fades to nothingness. The wind was also audible for much of the recording, which mostly just increased the noise level, which led to the occassional clipping of the microphone. A bird is audible far in the distance. Its call is composed of two identical parts, a high tone that fades in pitch and volume.

YL & JS

We recorded just a few centimeters above the east-west running section of CERA’s creek. Specifically, we recorded at a bend in the creek going through some tree roots that increased the turbulence of the creek, making its sounds recordable at all. The area was entirely surrounded by trees and brush, remaining flat to the North but quickly hitting a steep hill to the south. The creek itself was murky, with a few frogs and groups of cellar spiders living in it.

The loudest and most noticeable sound seems to be composed of two kinds of insect chirps, forming a solid band in the 4 – 6 kHz range. One seems to be a constant pitch in volume, while the other wobbles in pitch a few times each second. On the opposite end of the spectrum of noticeability, the creek itself sometimes burbles incredibly softly at around 2.5 kHz. Birdsong is occasionally audible, sounding very high and pure. Although all the calls seemed to follow the same pattern of a high tone (around 3.5 kHz) falling to a lower pitch before cutting off, they seemed to come in a call-and-response pattern – one bird, at a higher pitch would call, and a different, lower call would reply. At one point, there is a sharp crack as a twig might have broken under one of our feet.

YL & JS

This recording was taken just up the path from a creek and just around a bend from the open prairie (pictured below) , raised up into the air. The most pervasive sound through the recording is the constant humming/buzzing of the crickets, providing a base sound that all the other sounds stood out from. About 10 seconds into the recording a bird chimes in, chirping repeatedly in groups of 3-6 beats at a single pitch. As it proceeds, individual bugs/crickets/cicadas can be heard over the others in the crowded background as they briefly increase their volume or alter their pitch slightly. Far away in the distance, barely audible over the insects are the man-made sounds of machines and automobiles along the highway.

 

The sounds that we recorded:

While at CERA, we examined the sounds in three locations within the oak savanna. The audio file that we submitted is a combination of all three locations we compiled sounds from. The first 20 seconds is the first location, the second 20 seconds is the second location, and the final 20 seconds is the third location. In the first location we were surrounded by oak and shagbark hickory trees and plant life that was not very diverse. Roughly half of the sky was covered by oak branches in this area. We heard many sounds in this first area, including the calls of various insects comprising: crickets and cicadas, each of different lengths and speeds; both long and short bird calls coming from every direction; and vehicles driving along the interstate creating a deep whining sound almost like a strong wind. The second area we examined was still in the oak savanna but contained fewer trees and more diverse plant life than the first area. In this second setting, the whine coming from the interstate was louder and higher pitched; bird calls were louder, making the birds seem as if they were closer to us, and making it easier to identify that not only were the calls in response to one another, but each type of bird had its own unique call; there were the constant chirps and whirs of cicadas and chirps of other insects; and the wind was more noticeable as it ran through the plants and tree leaves surrounding us. The last area that we explored was directly next to an oak tree. The savanna covered half of the sky and the plant life was relatively diverse. The sounds that we heard were more muffled and condensed than the previous noises: the insects seemed further away, and the interstate seemed to omit a lower sound. The sound here was a lower pitch than that of the second location.

As I stepped into the overgrown prairie grass, the first thing I noticed was the insects. They reminded me of the constant hum of cicadas on the campus of Grinnell, however, the prairie insects were too consistent with their volume. The second thing I noticed was the calling of a crow in the distance. The crow seemed to “caw” every five seconds or so. If I listened very closely, a cricket can be heard very softly starting around the 15 second mark. Thankfully, man-made noise was non-existant in this recording, since I was very far away from the highway and the grain belt.