These waveforms show that all the clicks made by a Southern Cricket Frog will sound the same while each click by a Northern Cricket Frog may be a little different.  More importantly:
 
Southern Cricket Frogs “chirp” and Northern Cricket Frogs “rattle”.
 
The two bouts below are similar except that one is made of chirps and the other is made of rattles.
 
Southern Cricket Frog                                              Northern Cricket Frog
 
Why is this page here?
 
This page exists primarily to help participants in NCPARC’s Calling Amphibian Survey Program
use sounds to identify Northern Cricket Frogs (Acris crepitans) and Southern Cricket Frogs (A. gryllus)
in the region of North Carolina where either species may be encountered.
 
Please email me ASAP if you hear both species calling at a single pond!
 
Why?  Syntopic wetlands (sites with both species) appear to be uncommon and I want to visit them
for acoustic recordings as part of my research.  More importantly, I think documenting these special places will benefit the frogs.  I am concerned that cricket frogs could decline in the Southeast over the next decades and feel that it is important to locate the wetlands that support both species while the frogs are still abundant.
 
I am also interested in hearing from anyone who has recently identified cricket frogs by sound in North Carolina or adjacent areas of South Carolina and Virginia.
Where in North Carolina is this information useful?
 
The map shows the places where I have identified cricket frogs by sound through 2007.
I expect that Northern Cricket Frogs will be found in the Piedmont and closer to the big rivers in the upper Coastal Plain while Southern Cricket Frogs will be found in upland areas of the upper Coastal Plain (including the Sandhills) and throughout the lower Coastal Plain.  Adjacent areas may also have either species.
 
Conservatively, both species could be found in the upper Coastal Plain and adjacent areas in the lower Piedmont and lower Coastal Plain.
and look like:
Good luck! Please email me if you have questions or find something interesting!
syntopic site
Both species are audible at the start of this recording.  At the same time that the Green Treefrog joins in,
the Southern Cricket Frogs become quieter and the Northern Cricket Frogs are more distinct.  On a CASP route, the listener might not get closer than I was when I made this recording, so it is necessary to distinguish between the two species at this range.  This is just close enough to hear the clicks of individual frogs.
 
Clicks are made up of “pulses” and the two species sound different because their pulse patterns are different.  Southern Cricket Frogs have short pulses that are repeated quickly and regularly and become quieter
at the end of the click.  Northern Cricket Frogs have longer pulses that are repeated
more slowly and irregularly and do not become quiet.
 
                 Southern Cricket Frog clicks                                                  Northern Cricket Frog clicks
 
sound like:
How can cricket frogs be identified by sound?
 
Cricket frogs vocalize by making a “click” that is repeated in a “bout” from a few seconds to over a minute
in length.  Males of both species adjust bout structure when competing with each other, so it is too variable
to use for identification.  The two species have very different ways of making a single click, though,
and they can be identified by hearing the difference.  A chorus with both species sounds like this:
This page contains detailed information.  The key points are in green text.
Eastern Cricket Frog (Acris crepitans crepitans)
Coastal Plain Cricket Frog (Acris gryllus gryllus)
identifying cricket frogs by sound