Bald-faced hornets in Wisconsin
Yes — bald-faced hornets are recorded in Wisconsin. The GBIF biodiversity database holds 1,131 verified bald-faced hornet records from the state — ranking it 12th nationally. Sightings concentrate in July to September. Onset: immediate severe pain. Duration: swelling for several days.
| Verified records | 1,131 |
|---|---|
| Peak sightings | July 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 |
Bald-faced hornet bites in Wisconsin: what the mark looks like
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 deer fly bite — all of which are also recorded in Wisconsin.
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 Wisconsin
These are recorded in Wisconsin 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 | 1,131 | 894 | 292 |
Bald-faced hornet season in Wisconsin specifically
Records in Wisconsin concentrate in July to September, which is what local sighting data shows rather than a national average — seasonality shifts substantially with latitude. The general bite season in Wisconsin runs May to September.
Because enclosed grey paper nests the size of a football, hanging in trees, on sheds and under eaves, exposure in Wisconsin 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.
Month by month in Wisconsin
These are the 1,131 Wisconsin records broken out by the month they were recorded — not a national curve redrawn for the state. Records appear in 12 of the 12 months here. The single busiest month is August with 442 records (40% of the state total).
| Month | Records | Share |
|---|---|---|
| January | 2 | <1% |
| February | 1 | <1% |
| March | 6 | <1% |
| April | 20 | 2% |
| May | 45 | 4% |
| June | 56 | 5% |
| July | 154 | 14% |
| August | 442 | 40% |
| September | 271 | 24% |
| October | 85 | 8% |
| November | 16 | 1% |
| December | 10 | <1% |
Counts are observations submitted to GBIF, not bites. They tell you when the animal is out and being noticed in Wisconsin; they do not tell you how many people were bitten. The thinnest month with any record at all is February (1).
How Wisconsin compares
Across the 50 states with any bald-faced hornet records, Wisconsin ranks 12th with 1,131. The state directly above it is North Carolina (1,131). Directly below is New Jersey (1,090). The highest count anywhere is New York (3,286).
Inside Wisconsin itself the picture is different again: of the 18 biting species we track with records here, this one is 3rd and accounts for 12% of the 9,394 records logged in the state. A species can be common nationally and marginal in one state, or the reverse — which is the whole reason this page exists separately from the national guide.
Care
- leave the area quickly — this species pursues
- cold pack, antihistamine, pain relief
- adrenaline auto-injector if prescribed
Avoiding bald-faced hornets in Wisconsin
- never disturb an enclosed grey paper nest; have it removed professionally
- keep distance when mowing or strimming near trees
Questions
Are there bald-faced hornets in Wisconsin?
Yes. Wisconsin accounts for 1,131 verified records in GBIF, ranking it 12th among the 50 states with any records for this species, just behind North Carolina (1,131). Within Wisconsin it is 3rd of the 18 biting species we track here, at 12% of the state's records. Records reflect reporting effort as well as abundance.
When are bald-faced hornets active in Wisconsin?
Wisconsin records peak in July to September. The general bite season in Wisconsin runs May to September.
What does the bite look like?
a large, hot, red swelling with a central point, red. Often several — the colony defends aggressively.
Which month has the most sightings in Wisconsin?
August, with 442 of the 1,131 Wisconsin records (40%). Records appear in 12 of the 12 months here. This counts sightings submitted to GBIF, not bites.
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.
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