PEEC Amateur Naturalist: Tadpoles and Temporary Streams

PEEC Amateur Naturalist: Tadpoles and Temporary Streams
By ROBERT DRYJA

An estimated 88 percent of the miles of streams in New Mexico are intermittent as shown in the hydrographic map.

Extensive permanent streams exist only in the mountains of northeastern New Mexico. The Los Alamos area is typical of this pattern. The few perennial streams are in the higher elevations toward the Valles Caldera, while many intermittent and ephemeral streams are in the lower elevations toward the Rio Grande.

National Hydrography Dataset, http://nhd.usgs.gov. Courtesy/Robert Dryja

The temporary streams typically exist only during a few weeks of the summer months. Stream flow may vary greatly from one year to another. However, these streams provide the habitat for many kinds of animals. A distinct droning sound can be heard in the evening along former dry streambeds. This is not the brief chirping sound of crickets, but a sound that may continue for several seconds. A chorus of drones may be heard at some locations.

You are hearing the sound of adult frogs or toads calling for mates. The frogs are better at seeing you in the evening darkness than you are in seeing them. Further, they become silent when you come near. It takes some patient hunting with a flashlight to finally see one.

The tadpoles and eggs of frogs and toads are easier to locate during the day. They may be found in the still water of natural pools within the stream, rather than the moving water. Tadpoles are in a race with the possibility that their puddle will become dry shortly. Tadpoles therefore may grow from an egg to a froglet in as little as one month, depending upon the species and quality of its habitat. Warm water and lots of algae provide for a good habitat.

A pool in an intermittent stream bed. The still water is a good tadpole habitat. Photo by Robert Dryja

Looking closer. Photo by Robert Dryja

Two groups of tadpoles: One large tadpole is about to start the transition to dry land. In comparison, there are another 20 small tadpoles from a younger generation near it. Photo by Robert Dryja

The PEEC Nature Center has a colony of six young canyon tree frogs that were collected as tadpoles six weeks ago. They will be moving to the new Los Alamos County Nature Center. In the meantime, you can see them growing at the present building on Orange Street. Canyon tree frogs have large adhesive pads on the toes of all four legs. They can climb the sides of the rocks and plant branches extending upwards from stream pools. The tree frogs at PEEC also can climb the smooth glass walls of their terrarium home. The smaller frogs remain in place on the glass. However, the larger frogs may slide back down the glass or occasionally fall to the ground. Then they climb right back up again!

 

 

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