These frogs live in turbulent waters, where they spend much of their time clinging to river boulders, and a smaller amount of their time jumping from river boulder to river boulder (hence "Rock Skipper"). Occasionally one will spend some time on a leaf, which is handy for photography.

When clinging to the boulders they are amazingly well camouflaged. (There are two frogs in the second photo, in case you didn't notice.)

Unlike their cousins the Black-spotted Rock Skippers, these frogs were extremely jumpy, and I carefully pursued many but got photos of only a few before they leapt away.