Holorusia hespera
In 3 days ~20% in a week ~40%
Holorusia hespera, the giant western crane fly, is a species of crane fly in the family Tipulidae. It is found in western North America. H. hespera is the largest North American species of cranefly, with wings reaching lengths of 40 mm (1.6 in). The species is noted to lack wing interference patterning on the glossy amber colored wing surface, suggested to be a result of the wing thickness. The wing surfaces are textured with ridging and folds and the coloration is uniform across the wing. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States | |
| 2 | Yosemite National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Seattle | 🇺🇸 United States | |
| 2 | Vancouver | 🇨🇦 Canada | |
| 3 | Portland | 🇺🇸 United States | |
| 4 | San Francisco | 🇺🇸 United States | |
| 5 | Los Angeles | 🇺🇸 United States | |
| 6 | San Diego | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Giant Western Crane Fly sighting in Yosemite National Park on a given day, based on 17 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 85th 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.
May to September
In those months about 10% of wildlife watchers report a Giant Western Crane Fly in Yosemite National Park on a given day, against under 5% in October to April, the lowest months. Those are among Yosemite National Park's driest months, with about 30 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 Giant Western Crane Fly sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
Among the best
Of the 2 parks where we can rate Giant Western Crane Fly sightings, Yosemite National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Sequoia and Kings Canyon National Parks (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Giant Western Crane Fly is recorded against all the insects logged in Yosemite National Park (17 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.
