Hyalophora euryalus
In 3 days ~20% in a week ~40%
Hyalophora euryalus, the ceanothus silkmoth, is a moth of the family Saturniidae. The species was first described by Jean Baptiste Boisduval in 1855. It is found in the forests and valleys of the Pacific Northwest, but has been observed as south as Baja California.
It is a reddish-brown moth with black and white patterning spots. The postmedial band and various spots are black and white. The edges of the wings vary from light brown to gray. Its antennae are fluffy and black. The wingspan is 89–127 mm. Adults are on wing from January to July depending on the location. There is one generation per year.
It is found in the dry intermontane valleys and interior of British Columbia, Canada, (as far north as Prince George along the Fraser River) south to Baja California in Mexico. A subspecies, Hyalophora euryalus cedrocensis, is found on the Isla de Cedros, a small island off the west coast of Baja California, Mexico.
Other habitats include coastal rainforests, hardwood forests, montane forests, and juniper woodlands. The larvae feed on numerous hostplants including those in the Rhamnaceae (Ceanothus, Rhamnus californica), Ericaceae... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Redwood National Park | 🇺🇸 United States | |
| 2 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States | |
| 3 | Yosemite National Park | 🇺🇸 United States | |
| 4 | Great Bear Rainforest | 🇨🇦 Canada | |
| 5 | Pacific Rim National Park Reserve | 🇨🇦 Canada | |
| 6 | Glacier National Park | 🇺🇸 United States | |
| 7 | Olympic National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Portland | 🇺🇸 United States | |
| 2 | Vancouver | 🇨🇦 Canada | |
| 3 | San Francisco | 🇺🇸 United States | |
| 4 | San Diego | 🇺🇸 United States | |
| 5 | Los Angeles | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Ceanothus Silk Moth sighting in Yosemite National Park on a given day, based on 13 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 104th 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.
March
In that month about 20% of wildlife watchers report a Ceanothus Silk Moth in Yosemite National Park on a given day, against under 5% in April and July–February, the lowest months. That is one of Yosemite National Park's wettest months, with about 180 mm of rain against 25 mm in September.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Ceanothus Silk Moth sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 7 parks where we can rate Ceanothus Silk Moth sightings, Yosemite National Park ranks 3rd at about 10%, level with the leaders once rounded. The best odds are in Redwood National Park (United States, about 10%) and Sequoia and Kings Canyon National Parks (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Ceanothus Silk Moth is recorded against all the insects logged in Yosemite National Park (13 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.
