Vespula pensylvanica
In 3 days ~30% in a week ~60%
Vespula pensylvanica, the western yellowjacket (western yellow jacket), is a Nearctic species of wasp in the genus Vespula. It is native to regions of North America, largely in areas with northern temperate climates. Its reproductive behavior is constrained by cold weather, which successfully reduces the number of western yellowjackets in cold months. However, in the absence of cold weather, this wasp's population can explode. The western yellowjacket has become particularly invasive in the Hawaiian Islands, resulting in their label as a major pest.
V. pensylvanica was originally named by de Saussure in 1857; it falls into the subgenus Paravespula, within Vespula. Paravespula consists of 11 species, which have been divided into four groups on the basis of morphological differences. V. pensylvanica falls into the same group as V. germanica. With the exception of Allovespula, the subgenera recognized within Vespula are natural groups. The separation of Rugovespula and Paravespula appears to be monophyletic; however, this is not well established.
The western yellowjacket shares the basic yellow and black pattern with other... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States | |
| 2 | Zion National Park | 🇺🇸 United States | |
| 3 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States | |
| 4 | Grand Canyon National Park | 🇺🇸 United States | |
| 5 | Yosemite National Park | 🇺🇸 United States | |
| 6 | Olympic National Park | 🇺🇸 United States | |
| 7 | Great Bear Rainforest | 🇨🇦 Canada | |
| 8 | Rocky Mountain National Park | 🇺🇸 United States | |
| 9 | Joshua Tree National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Salt Lake City | 🇺🇸 United States | |
| 2 | Sacramento | 🇺🇸 United States | |
| 3 | Calgary | 🇨🇦 Canada | |
| 4 | Denver | 🇺🇸 United States | |
| 5 | San Francisco | 🇺🇸 United States | |
| 6 | Vancouver | 🇨🇦 Canada | |
| 7 | Edmonton | 🇨🇦 Canada | |
| 8 | Portland | 🇺🇸 United States | |
| 9 | Seattle | 🇺🇸 United States | |
| 10 | San Diego | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Western Yellowjacket sighting in Zion National Park on a given day, based on 16 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 28th most-seen of the 114 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 60%, if each day is a fresh chance.
January
In that month about 30% of wildlife watchers report a Western Yellowjacket in Zion National Park on a given day, against under 5% in February–May, August and December, the lowest months. That is one of Zion National Park's wettest months, with about 70 mm of rain against almost none in June.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Western Yellowjacket sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 9
Of the 9 parks where we can rate Western Yellowjacket sightings, Zion National Park ranks 2nd at about 10%. The best odds are in Channel Islands National Park (United States, about 20%).
GBIF citizen-science records
It is estimated from how often the Western Yellowjacket is recorded against all the insects logged in Zion National Park (16 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.
