I think my C. cranwelli is calling/singing, but I'm new to frogs. He is making occasional sets of 4 - 5 chirps. I only question it because he's less than 5cm/2in in length and I don't know at what size or age it's normal to begin vocalizing. Maybe the squeaking or "chirps" are really him scratching the bottom of his Kritter Keeper trying to dig deeper? He's in about 1.5 inches of damp coco-fiber and has a water dish he can soak in.
Please educate me!
Also, how did you react the first time you heard your pac(s) vocalizing?