I found this green tree frog (Hyla cinerea) last year when I was collecting freshwater limpets for an independent study at Halfway Swamp Creek (near Lake Marion, SC*). This guy is a little more interesting to look at than a freshwater limpet.
*Also the site of an alligator attack last year in which a man lost his arm
posted by Jacob Herman
2 comments:
Nice picture and story, Jacob! We found these guys sometimes in northern NC last summer when I was working for a UNC PhD student along the Roanoke River. We also saw what I think was H. squirella, and both species liked to hide in the openings of vertical PVC pipes used to mark river flooding levels.
On a side note, I found an interesting website about the frogs of Georgia. The author, Walter Knapp included the frog calls as well as call sonograms in the species descriptions: http://gruagach.home.mindspring.com/
sonograms/Green.TF.Sono.jpg
This one is for Hyla cinerea, showing both male breeding and territorial calls. From what I could gather, the technology used is similar to medical ultrasounds. The sonograms give a visual representation of tonal frequency and rhythm, which is very cool! By doing some quick searches in the Web of Knowledge article database I found that some studies have used similar frequency spectra technology to discern intraspecific variation in advertisement calls. Obviously, there's a lot more in a frog call than we can gather by ear.
Those PVC pipes are so effective that they're actually used as a sampling method for tree frogs!
Sonograms aren't exactly like ultrasounds, which use very low-frequency sound waves to "bounce back" an image. Sonograms are a way of visually depicting a sound, where the y-axis shows frequency (i.e., pitch), the x-axis shows time (hence the rhythmic component)and the darkness shows relative loudness. Come by my lab sometime and I can show you sonograms of gray tree frog calls!
(posted by Allison Welch)
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