An online to portal to learn a bit more about some frogs and their calls.
Rio Grande Chirping Frog Eleutherodactylus (cystignathoides) campi
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.
This species range is expanding rapidly in Texas. When I lived on the west side of Houston in the late 1970s, I had never seen it. By the early 1980s, it was abundant in my old neighborhood. And the expansion is continuing through both frog movement and our increased discovery of the species.
Here's a map I made in 2015 of the known records for the species in Texas:
In January 2021, I made a new map based on the records available from above plus new records from iNaturalist. You can see how many of the missing counties have been filled in plus how much further north it has been documented. It's range into the hill country is difficult to identify due to confusion with the very similar Cliff Chirping Frog which occurs there.
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.
These frogs also have a longer "trilled" call which they make. It seems to me that the longer trill is the real call and the short peeps are just working up to it.
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.
* It is worth adding that in 2020, a study elevated the Rio Grande Chirping Frog (Eleutherodactylus cystignathoides campi) to species status Eleutherodactylus campi. The original E. cystignathoides is now restricted to the coastal plains of the gulf coast of Mexico. We will have to see if that taxonomy is accepted. This group still needs a lot more work.
I hear these in my backyard all the time here in Spring (North of Houston) Texas.
I went out with my flashlight last night and located one by the house - it was about 10mm long and sitting in the middle of a leaf of an Elephant Ear Plant. The leaf shape was acting like a horn and seemed to be amplifying the sound.
The ones here don't make the "trill" sound much, but often call out four "tweets" in a row, pause, then another four tweets.
My wife's old friend used to think they were birds chirping all night long.
Congratulations on finding the little frog. They can be really tough to locate by their calls. Interestingly, when I lived and explored around Houston in the early 1980s, these frogs were not present. They were introduced sometime in the late 80s and have become abundant since that time.
Sorry, I didn't see this comment earlier. In Florida you have a healthy population of Greenhouse Frogs (E. planirostris). I've never seen any documentation of the Rio Grande Chirpers there. They are very similar looking and sound rather similar as well. I know Louisiana has both species and southeastern Texas is now reporting Greenhouse Frogs to go with their established populations of Rio Grande Chirpers. (https://frogcalls.blogspot.com/2018/05/greenhouse-frog-eleutherodactylus.html).
Hi, I just wanted to say that this is a seriously impressive blog! The words encyclopedic and massive come to mind. Outstanding work (especially the recordings and spectrograms). Best wishes!
Thanks. I hope to be adding some new species early next year. Kind of a labor of love? It's too bad there isn't an "xeno-canto" type repository for non-avian calls. I upload a lot to iNat, but it isn't the same.
I hear these in my backyard all the time here in Spring (North of Houston) Texas.
ReplyDeleteI went out with my flashlight last night and located one by the house - it was about 10mm long and sitting in the middle of a leaf of an Elephant Ear Plant. The leaf shape was acting like a horn and seemed to be amplifying the sound.
The ones here don't make the "trill" sound much, but often call out four "tweets" in a row, pause, then another four tweets.
My wife's old friend used to think they were birds chirping all night long.
Congratulations on finding the little frog. They can be really tough to locate by their calls.
DeleteInterestingly, when I lived and explored around Houston in the early 1980s, these frogs were not present. They were introduced sometime in the late 80s and have become abundant since that time.
There is a healthy population here in Daytona Florida no one seems to know about on the internet at least.
ReplyDeleteSorry, I didn't see this comment earlier. In Florida you have a healthy population of Greenhouse Frogs (E. planirostris). I've never seen any documentation of the Rio Grande Chirpers there.
DeleteThey are very similar looking and sound rather similar as well. I know Louisiana has both species and southeastern Texas is now reporting Greenhouse Frogs to go with their established populations of Rio Grande Chirpers.
(https://frogcalls.blogspot.com/2018/05/greenhouse-frog-eleutherodactylus.html).
Hi, I just wanted to say that this is a seriously impressive blog! The words encyclopedic and massive come to mind. Outstanding work (especially the recordings and spectrograms). Best wishes!
ReplyDeleteThanks. I hope to be adding some new species early next year. Kind of a labor of love? It's too bad there isn't an "xeno-canto" type repository for non-avian calls. I upload a lot to iNat, but it isn't the same.
Delete