The call of this species is a long, whistled trill
Incilius valliceps call
There is sometimes confusion about "Gulf Coast Toads" and the name Incilius (Bufo) valliceps as this name used to be applied to toads from the United States down to Costa Rica. Subsequent research has shown that the toads of Central America and southern Mexico are the true Incilius valliceps white the more familiar northern populations in the US and northeast Mexico are correctly known as Incilius nebulifer. The toads look very similar and their calls are similar.
Many US field guides and other resources still incorrectly refer to the northern population as Incilius valliceps.