new life at Stuart Creek

by Jen Stanfield

Earlier this spring, I hiked through Stuart Creek at Glen Oaks Ranch to monitor for invasive plants along the banks. Spring was in full force; the foliage displayed electric green hues, birds were chirping, insects were buzzing and, woohoo! — the spider webs were plentiful. As I made my way upstream, I caught a glimpse of something unusual attached to a nearby rock and, moving closer to investigate, I was delighted to discover … frog eggs! ​

After asking a few colleagues to weigh in on the identification, it appears that these were foothill yellow-legged frog (Rana boylii) eggs. Listed by the California Department of Fish and Wildlife as a species of special concern, the foothill yellow-legged frog once occupied a large geographic range spanning from Oregon to southern California along the coast range and inland foothills. According to californiaherps.com, many of the foothill populations are nearing extinction, though the northern Sierra Nevada and North Coast populations appear to be doing well.

About a week later, I returned to the vicinity of the egg mass to see if the eggs had hatched. Though the original mass had disappeared, in its place were three new egg masses. Intrigued by this discovery, I did some research and learned that this species of frog displays a behavior termed ‘breeding site fidelity,’ meaning that the frogs return to the same location to breed each season. Some research even suggests that an entire local population will lay eggs in the same area of a stream, which would explain the various egg masses I had found.

Upon returning a few weeks later, quite a number of small tadpoles had dispersed downstream of the egg mass location. I couldn’t help but be reminded of how youth all around the county have been graduating — just like these eggs had graduated to tadpoles!  We are all pleased that Stuart Creek provides excellent habitat to these interesting amphibians — and hope that they continue to thrive.

Jen Stanfield is assistant stewardship project manager at Sonoma Land Trust.