Western Tussock Moth

Western Tussock Moth

Orgyia vetusta

Daily sighting probability ~10% · With luck
at San Diego

In 3 days ~20% in a week ~30%

169 Verified sightings at San Diego
13 In 1 park From 2019 to 2026
April Best month
☀️ Diurnal When it's spotted

About the Western Tussock Moth

Orgyia vetusta, also known as the western tussock moth, formerly Hemerocampa vetusta, is a moth found in the Pacific States and British Columbia. The species is dimorphic; the females are flightless. The Western tussock moth is reported on virtually all California oak species as well as various fruit and nut trees, ceanothus, hawthorn, manzanita, pyracantha, toyon, walnut, and willow. There is an isolated population in Boise County, Idaho. This species has also been seen in U.S. gulf coast states such as Louisiana..

Tussock moth eggs are white and are laid in a mass, which overwinters. The female covers the eggs with setae. The caterpillars emerge in early spring (February-May) and exhibit minimal disperse via ballooning, a process by while caterpillars hang from silk threads and are spread by wind. This is also observed in other species within the family Erebidae, such as Lymantria dispar dispar. Larvae have hairs that may cause minor skin irritation or allergic reactions in humans. Adults emerge from cocoons between June and August.

Tussock moth caterpillars can cause damage to citrus orchards in Southern California.... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Channel Islands National Park 🇺🇸 United States
~10%

More parks will be added in future updates.

Cities Where Found

# City Country Daily sighting probability
1 San Diego 🇺🇸 United States
~10%
2 San Francisco 🇺🇸 United States
~10%
3 Sacramento 🇺🇸 United States
<5%
4 Los Angeles 🇺🇸 United States
<5%

Before you go

What are the chances of seeing a Western Tussock Moth in San Diego?

With luck

About 10% of wildlife watchers report a Western Tussock Moth sighting in San Diego on a given day, based on 169 verified sightings from GBIF citizen-science data. It is the 70th most-seen of the 693 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.

When is the best time to see a Western Tussock Moth in San Diego?

February to May

In those months about 10% of wildlife watchers report a Western Tussock Moth in San Diego on a given day, against under 5% in June to January, the lowest months.

What time of day is best to see a Western Tussock Moth?

Between noon and 3 pm

Across all the parks we cover, that three-hour window holds the most Western Tussock 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.

Is San Diego the best place to see a Western Tussock Moth?

Yes

Of the 4 cities where we can rate Western Tussock Moth sightings, San Diego has the highest daily chance: about 10%. Next come San Francisco (United States, about 10%) and Sacramento (United States, under 5%).

Which relatives of the Western Tussock Moth live in San Diego?

Same family: Erebidae

The closest relatives of the Western Tussock Moth that you can see in San Diego (family Erebidae, Underwing, Tiger, Tussock, and Allied Moths) are Salt Marsh Moth (about 10%) and Painted Tiger Moth (about 10%), with each one's daily chance of a sighting.

Where does the Western Tussock Moth sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Western Tussock Moth is recorded against all the insects logged in San Diego (169 verified sightings), 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.

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