The Crawfish Frog (Lithobates areolatus) is a seldom seen frog of the prairies and open woodlands from eastern Texas and north up into SE Kansas then across to the Mississippi valley down to the gulf coast.
Although it has an apparently large geographic range, it has a somewhat spotty distribution which may be due do the difficulty if finding this frog. Even in its range, it is a species of frog that most people are unfamiliar with. This is likely due to the fact that it spends most of its time underground in burrows. It often uses crawfish burrows and eats crawfish (along with anything else it can swallow). This is where the species gets its common name. It apparently only comes to the surface after heavy rains flood its burrows bringing it to the up to chorus and breed.
These frogs we calling from a flooded patch of prairie/pasture close to the Attwater's Prairie Chicken National Wildlife Refuge in Colorado County, Texas. It was mild March evening and it had rained heavily in the preceding two days producing flooding patches among the remnant prairie grasslands of this region.
Although I heard many dozens of these frogs calling on this particular night, I had been exploring this area for several decades, both day and night, winter and summer. Yet I had never encountered them before because I hadn't been there on the right night at the right time.
The call is usually described as a "snore" which is a fairly apt description. (In this recording, you can hear the upward trilling "fingernail across a comb" calls of the Cajun Chorus Frog Pseudacris fouquettei in the background).
Interestingly, when you look at the spectrograph of their calls, you see that there is a descending higher pitched part to the call as well as the upward slurred snore.
You normally have trouble hearing the downward "whistle" over the loud snore, but I have edited out a selection of three calls here where the individual frog was further away and the whistle stands out more.
Staying with the "snoring" motif, the whistle sounds like the exaggerated whistled exhale that some snorers produce between snores, although in this case it is simultaneous with the snore.
© Chris Harrison 2015
No comments:
Post a Comment