Earth Notes - Ephemeral Pools

Flagstaff, AZ – Earth Notes: Ephemeral Pools

Colorado Plateau wildlife is adapted to a dry climate but when there's water, many animals take advantage of it, including the region's amphibians.

They can be noisy. Chorus and canyon tree frogs seek clear meltwater pools for breeding in March and April. Singing males set up small territories on poolside rocks or sticks, sometimes pushing each other like tiny sumo wrestlers. At elevations where ice forms on the water at night, the early spring breeders will sing during bright, sunny days.

Soon females arrive to lay eggs, which don't have shells and have to be laid in water. After they hatch, a week or two later, the resulting tadpoles feed on detritus and algae. If the water persists long enough, those tadpoles become tiny frogs within about a month. Tiger salamanders share some of the same breeding pools though their offspring often end up feeding on the nearby tadpoles.

In Flagstaff's Buffalo Park, a shallow basin formerly used for watering buffalo provides good amphibian habitat after wet winters. Naturalist Zack Zdinak and biologist Lisa Gelches have been monitoring it for years.

In 2001, frogs and tiger salamanders began breeding there in late March. After four dry springs, good snowfall in early 2006 melted and refilled the pool. The frogs began calling in mid March, and were soon followed by energetic tadpoles.

The next time you see a big puddle left over from winter, take a moment to watch and listen for the Southwest's cold-weather frogs.

-Zackery Zdinak