Dan Dugan wrote:
>
> >The other unique thing about these frogs is that their calls are not
> >confined to a single frequency pattern like other Georgia frogs. Though
> >each call is fairly narrow in frequency, they cover a couple thousand
> >cycles in variations call to call with no apparent pattern in doing so.
>
> Very interesting! I wonder if they tune around other frogs singing in the
> area.
I do know of other frog combinations where the calls are tuned to fit in
different frequencies but in this case, there were no other frogs except
a occasional green treefrog in the distance. And these are a exotic
import for our area.
It may have to do with the variation in size. Since they hatch directly
into frogs from the eggs, there is a pretty wide variability in size.
I've no idea how many sizes are calling, but it's certainly more than
just the "large" ones.
If you check out the sonogram, you will see that the variation is way
too irregular to be adjusting to something.
http://wwknapp.home.mindspring.com/docs/greenhouse.frog.html
The call recording on my page is a borrowed one as until last week I'd
not met this frog, I've been working on my recordings this afternoon,
removing air conditioners and so on as best I can. But what I got is
much the same. I'll get my own recording into the page in the next few days.
Yes, it's interesting, frogs tend to call along specific frequency
levels, which is fairly closely related to size. They are not only all
over the map for frequency, but a bit low frequency for their size. I
believe the calls are so soft because they don't have to go to water to
breed, but do so where they live. So they don't have to attract in the
females from any distance.
Walt
________________________________________________________________________
________________________________________________________________________
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|