Thallophaga hyperborea
In 3 days ~20% in a week ~40%
Thallophaga hyperborea, the northern thallophaga, is a moth of the family Geometridae. The species was described by George Duryea Hulst in 1900. It occurs in Western North America, from California, USA, to British Columbia, Canada, and the Alaskan Panhandle.
The wingspan is 30–37 mm (1.2–1.5 in). Adults emerge from April to May. The larvae feed on western hemlock, Douglas fir, red cedar, and other fir species. The moth has also been recorded on willow and alder, as well as other conifers. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Redwood National Park | 🇺🇸 United States |
More parks will be added in future updates.
With luck
About 10% of wildlife watchers report a Northern Thallophaga sighting in Redwood National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 85th most-seen of the 101 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.
April–May and July
In those months about 10% of wildlife watchers report a Northern Thallophaga in Redwood National Park on a given day, against under 5% in June and August–March, the lowest months. Those are among Redwood National Park's driest months, with about 90 mm of rain a month against 360 mm in January.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Northern Thallophaga sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Only Redwood National Park, in our data
Redwood National Park is the only park on Wallace's Line with enough records to rate Northern Thallophaga sightings: about 10% of wildlife watchers there report one on a given day.
Same family: Geometridae
The closest relatives of the Northern Thallophaga that you can see in Redwood National Park (family Geometridae, Geometer Moths) are California Black (about 20%), Omnivorous Looper (about 10%) and Pale Beauty (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Northern Thallophaga is recorded against all the insects logged in Redwood National Park (5 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.
