The tiny Rio Grande Chirping Frog is native to southernmost Texas and then into Mexico. However, they have been widely introduced into larger cities in Texas and other states. Their chirping calls can be heard any warm night in my backyard in San Antonio, Texas.
The photo and recordings are from my backyard, although not necessarily of the same frog.
The most typical call is a short sharp chirp/cheep call. The chirps are fast and each chirp increases in pitch.
Here's a closer view of the short call, showing how each "chirp" slides up in pitch.
Here is the waveform and spectrograph for the first three seconds of this recording:
Here's a side by side comparison of the two types of call notes. This comparison was created by cutting out some of the intervening notes in a long series of calls.
and here's the sonographic representation of that recording.
© Chris Harrison 2012