South Central Texas Spadefoot ToadsScaphiopus hurterii versus Scaphiophus couchii

One of the call differences I have needed to learn to distinguish is the "dyspeptic groans" of the two species of Spadefoot Toads (genus Scaphiopus) that occur in my area.

Hurter's Spadefoot Toad (Scaphiopus hurterii) is closely related to the Eastern Spadefoot Toad (Scaphiopus holbrooki) and occupies the eastern half of Texas.  It is usually greenish or brownish with vague striped pattern on its back.

The widespread Spadefoot of the southwestern US is the Couch's Spadefoot (Scaphiopus couchii).  In Texas, it is found in the western 2/3 of the state.  Couch's Spadefoot is highly variable in pattern, but usually shows some pattern of a yellowish or greenish background with an irregular mottled or spotted black pattern on the back.  It rarely shows the striping seen in S. hurterii.

Not only is there a superficial resemblance in size and coloration, but these two species have similar calls.  Their calls are often described as "dyspeptic groans" and can sound similar from a distance.

Here is the call of Scaphiopus hurterii. This species has a "doppler" effect to its call where its shorter notes descend in pitch.  It is somewhat remniscent of impersonating the sound of a car passing at high speed.

Scaphiopus hurterii call mp3

And here is the call of Scaphiopus couchii. This species has a call that goes up then down in pitch and is usually longer in duration than the call of the Hurter's Spadefoot.

Scaphiopus couchii call - mp3

They don't sound that similar up close, but from a distance they can be suggestive of each other.  But while they are similar sounding, the "shape" of the call notes and their length is different.  Here is a few seconds of S. hurterii followed by a few seconds of S. couchii.

This difference is relatively easy to see when you look at the spectrograph of their call notes.  Here is the spectrograph of a single S. hurterii call followed by a single S. couchii call.

The darkest line on the spectrograph represents the carrier (dominant) frequency of the call.  I have drawn in a red line indicating the approximate shape (slope) of the call in an effort to demontrate the differences in their relative shapes.

Here's a comparison of a chorus of S. hurteri from DeWitt County, Texas -


Hurter's Spadefoot Chorus - DeWitt County

and a chorus of S. couchii from Dimmitt County, Texas -


Couch's Spadefoot Chorus - Dimmit County

Once you learn the general differences in length and shape, their calls are not too difficult to tell apart.

© Chris Harrison 2014

Hurter's Spadefoot (Scaphiopus hurterii)

Hurter's Spadefoot (Scaphiopus hurterii)
Dewitt County, Texas

Hurter's Spadefoot (Scaphiopus hurterii) used to be regarded as a subspecies of the Eastern Spadefoot (Scaphiopus holbrooki).  Hurter's Spadefoot is found west of the Mississippi in Louisiana, Arkansas, and eastern Oklahoma and Texas.

Like all Spadefoots (family Pelobatidae), Hurter's Spadefoot is a fossorial species that only comes to the surface after heavy rains.  They breed explosively after those rains, the tadpoles develop quickly and they burrow down into the soil again until the next rain.

Hurter's Spadefoot (Scaphiopus hurterii)
Brazos County, Texas

Their explosive call can almost lift them out of the water.  Here's a male calling in DeWitt County, Texas -

and here he is in action -

These Hurter's Spadefoot were recorded at the western edge of their range in Atascosa County, Texas.  


In this area, their range overlaps with the western Couch's Spadefoot (Scaphiopus couchii).

The calls of the two species are superficially similar in that they are both a nasal "waaahh", but Hurter's Spadefoot call is shorter, given more rapidly and is descending in pitch throughout.  It has almost a "doppler effect" sound.  It almost sounds like someone trying to impersonate the sound of a race car going by very quickly.

Couch's Spadefoot call is slower and ascends before descending.

© Chris Harrison 2013