Rana sierrae
Silhouette: Beth Reinke · PhyloPic
In 3 days ~40% in a week ~70%
The Sierra Nevada yellow-legged frog (Rana sierrae) is a true frog endemic to the Sierra Nevada of California and Nevada in the United States. R. sierrae was formerly considered R. muscosa, until a 2007 study identified populations north of the Middle Fork Kings River (north of the Monarch Divide and Mather Pass in Kings Canyon National Park) as R. sierrae, with R. muscosa then confined to the southern Sierra Nevada, south of the Middle Fork Kings River and west of the Sierra Crest, and within the transverse ranges of southern California.
Once abundant in the Sierra Nevada, some estimates suggest populations of R. sierrae have declined over 90% (although other agency estimates suggest the declines for R. sierrae may have been around 70%, when comparing historic vs occupied localities, as of 2011). The potential ecological effects of these declines are not fully known, but the species was once highly abundant in the Sierra Nevada, and is therefore likely important for nutrient and energy cycling in alpine aquatic and terrestrial ecosystems.
Despite historic declines, long term monitoring work in Yosemite National Park suggests a trend toward recovery, in part due to cessation of fish stocking in remote wilderness areas and physical removal of non-native trout, plus reduced susceptibility over time among some populations to the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the amphibian disease chytridiomycosis. This research found an overall sevenfold increase in abundance of R. sierrae in Yosemite during the ~20-year study period (an 11% per year increase). Additionally, direct management actions, including translocation of adult frogs from populations that are persisting with Bd, and captive-rearing at zoos, have shown great promise for helping recover these imperiled populations. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Yosemite National Park | 🇺🇸 United States | |
| 2 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Sierra Nevada Yellow-legged Frog sighting in Yosemite National Park on a given day, based on 126 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 4th most-seen of the 9 amphibians we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
August
In that month about 30% of wildlife watchers report a Sierra Nevada Yellow-legged Frog in Yosemite National Park on a given day, against under 5% in November to May, the lowest months. That is one of Yosemite National Park's driest months, with about 30 mm of rain against 220 mm in January.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Sierra Nevada Yellow-legged Frog sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 2 parks where we can rate Sierra Nevada Yellow-legged Frog sightings, Yosemite National Park has the highest daily chance: about 10%. Next come Sequoia and Kings Canyon National Parks (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Sierra Nevada Yellow-legged Frog is recorded against all the amphibians logged in Yosemite National Park (126 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
