Hemileuca eglanterina
In 3 days ~20% in a week ~40%
The sheep moth, or common sheep moth (Hemileuca eglanterina), is a member of the family Saturniidae of silk moths and is native to western North America. In California, its range is west of the Sierran crest and the mountains of Southern California, ranging near to the coast. The moth is dayflying and appears in summer. It feeds on plants of three genera: Ceanothus, Rhamnus (including coffeeberry), and Rosa. Nuttall's sheep moth and one other species are similar, occurring in sagebrush areas east of the Sierra Nevada. The species was first described by Jean Baptiste Boisduval in 1852.
The sheep moth has a 5.5-8.5 centimeter wingspan and a relatively slender body. Its forewings are pink with a yellow streak in the middle and the hindwings are yellowish with variable black markings. There is an all-black form near Mount Shasta. The larvae are black with branched yellowish spines that become orange in later development and an orange-brown head. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Grand Teton National Park | 🇺🇸 United States | |
| 2 | Glacier National Park | 🇺🇸 United States | |
| 3 | Yosemite National Park | 🇺🇸 United States | |
| 4 | Olympic National Park | 🇺🇸 United States | |
| 5 | Yellowstone National Park | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Western Sheep Moth sighting in Yosemite National Park on a given day, based on 14 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 98th most-seen of the 227 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
June to September
In those months about 10% of wildlife watchers report a Western Sheep Moth in Yosemite National Park on a given day, against under 5% in October to May, the lowest months. Those are among Yosemite National Park's driest months, with about 25 mm of rain a month against 220 mm in January.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Western Sheep Moth sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 5
Of the 5 parks where we can rate Western Sheep Moth sightings, Yosemite National Park ranks 3rd at about 10%. The best odds are in Grand Teton National Park (United States, about 20%) and Glacier National Park (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Western Sheep Moth is recorded against all the insects logged in Yosemite National Park (14 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.
