Bald-faced hornet bites in Colorado
Colorado has 476 verified bald-faced hornet records in the GBIF biodiversity database — ranking it 22th nationally. Sightings concentrate in June to September. The bite itself appears immediate severe pain and lasts swelling for several days.
| Verified records | 476 |
|---|---|
| Peak sightings | June to September |
| State bite season | May to September |
| Active | daytime |
| Habitat | enclosed grey paper nests the size of a football, hanging in trees, on sheds and under eaves |
| Bite appears | immediate severe pain |
Identifying it in Colorado
Technically a large yellowjacket, black with an ivory-white face, and the most defensive of the group. Multiple stings during a single encounter are typical because the colony responds together and follows for a distance.
Locally, the species most often confused with it are honey bee sting, paper wasp sting, wolf spider bite — all of which are also recorded in Colorado.
Seek medical care if
Call emergency services now for difficulty breathing, swelling of the lips, tongue or throat, dizziness or fainting, or hives spreading away from the bite.
- breathing difficulty, throat tightness, faintness, hives away from the site
- multiple stings
- stings to the face or mouth
What else it could be in Colorado
These are recorded in Colorado too and are the ones most often confused with it here. The differences below are the ones that actually separate them.
| Bald-faced hornet sting | Paper wasp sting | Yellowjacket sting | |
|---|---|---|---|
| Pattern | often several — the colony defends aggressively | usually single | single or several — this wasp can sting repeatedly |
| Where on body | head, neck, arms | hands, head, arms — often while gardening or opening a shutter | hands, face, neck |
| Appears | immediate severe pain | immediate sharp pain | immediate sharp pain |
| Records here | 476 | 2,136 | 10 |
Season in Colorado specifically
Records in Colorado concentrate in June to September, which is what local sighting data shows rather than a national average — seasonality shifts substantially with latitude. The general bite season in Colorado runs May to September.
Because enclosed grey paper nests the size of a football, hanging in trees, on sheds and under eaves, exposure in Colorado tends to be concentrated in specific places rather than spread evenly — which is why a bite history ("where were you in the 24 hours before?") narrows the answer faster than the appearance of the mark.
Care
- leave the area quickly — this species pursues
- cold pack, antihistamine, pain relief
- adrenaline auto-injector if prescribed
Avoiding them in Colorado
- never disturb an enclosed grey paper nest; have it removed professionally
- keep distance when mowing or strimming near trees
Questions
When are bald-faced hornets active in Colorado?
Colorado records peak in June to September. The general bite season in Colorado runs May to September.
Are they common in Colorado?
Colorado accounts for 476 verified records in GBIF, ranking it 22th among states for this species. Records reflect reporting effort as well as abundance.
What does the bite look like?
a large, hot, red swelling with a central point, red. Often several — the colony defends aggressively.
Get a photo assessment in the app
Everything above is free to read. The app adds what a page cannot: point your camera at the bite and get an assessment of the most likely cause, a severity read, and a day-by-day care plan — including the specific signs that mean you should be seen.
iPhone and iPad. Free to download.