Orgyia definita
In 3 days ~10% in a week ~30%
Orgyia definita, the definite tussock moth or definite-marked tussock moth, is a moth of the family Erebidae. It was first described by Alpheus Spring Packard in 1865. The species is found in eastern North America from Minnesota to New Brunswick and south to South Carolina, Mississippi, and Louisiana.
The wingspan is about 30 mm for males; females are wingless. The larvae feed on Salix, Quercus, Tilia, Ulmus, Betula, Acer rubrum, and Hamamelis virginiana. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 2 | Shenandoah National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Montreal | 🇨🇦 Canada | |
| 2 | Toronto | 🇨🇦 Canada | |
| 3 | Washington | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Definite Tussock Moth sighting in Shenandoah National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 447th most-seen of the 723 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
September
In that month about 10% of wildlife watchers report a Definite Tussock Moth in Shenandoah National Park on a given day, against under 5% in October to August, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Definite Tussock Moth sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 2 parks where we can rate Definite Tussock Moth sightings, Shenandoah National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Great Smoky Mountains National Park (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Definite Tussock Moth is recorded against all the insects logged in Shenandoah National Park (9 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.
