Bald Faced Hornet Queen Identification: Size and Season

Size and season together identify a queen; queens and workers otherwise look the same. Wikipedia notes that queens and workers have similar body shapes and that queens are always larger than the workers in their own colony, although sizes vary between nests.

• Size. PestWorld gives queens about 3/4 inch (18-20 mm) and workers 1/2 to 5/8 inch (12-15 mm). Penn State Extension gives the whole colony a range of 13-20 mm, with queens the largest. A bald-faced hornet close to 3/4 inch or more is probably a queen.
• Spring, alone. Fertilised queens are the only members that survive winter (PestWorld, Penn State). As the weather warms in April or May each queen becomes active, chooses a site and starts a nest (University of Minnesota Extension), building the first cells and raising the first workers herself (Penn State). A single large bald-faced hornet in spring, especially one working on a small paper nest, is a queen.
• Late summer and fall. In late summer and early fall the old queen lays eggs that become males and new queens (Wikipedia). Several extra-large individuals around a big nest at this time may be new queens.
• After the first frosts. Most of the colony dies before or shortly after the first hard frost (Penn State); UMN puts it at freezing temperatures in the mid-to-upper 20s °F. A large bald-faced hornet found after that in a sheltered spot is almost certainly a new queen looking for somewhere to overwinter.

It is a large black wasp with ivory-white markings on the face and white marks on the thorax, legs and abdomen (Penn State Extension); Wikipedia describes three white stripes at the end of the body, and PestWorld two slanted lines running from the middle of the body towards the head. UMN gives about 7/8 inch for the species overall.

Despite the name, Wikipedia says it is technically a yellowjacket wasp, not one of the true hornets in the genus *Vespa*. It lives across North America and is most common in the southeastern US (Wikipedia). For yellow-and-black relatives see wasp, hornet and yellowjacket identification.

The nest is an enclosed grey paper ball, usually at least 3 feet off the ground in trees, shrubs, overhangs, utility poles or on buildings (PestWorld, Penn State). PestWorld gives up to 14 inches across and more than 24 inches long; Penn State up to 24 inches tall and 18 inches across.

Numbers vary by source: 100 to 400 members at peak (PestWorld), upwards of 300 in Pennsylvania (Penn State), and 400 to 700 workers, the largest colonies in the genus (Wikipedia). A colony lasts about four to five months depending on latitude (Wikipedia). Nests are not reused the following year: UMN says yellowjackets do not reuse nests, and the bald-faced hornet is a yellowjacket. See bee and wasp stings for sting care.

Only if it is where people walk. UMN's advice: if the nest is out of the way, ignore it; if it is in a high-traffic area such as a walkway or doorway, you may want to take control measures. Penn State says nests within 10 feet of building entrances should be removed by professionals, and PestWorld advises against removing one yourself because the hornets defend the nest aggressively.

Leaving a distant nest has benefits. Bald-faced hornets prey on flies, caterpillars and spiders (Wikipedia), and Penn State notes they reduce populations of unwanted insects. The colony dies with the hard frosts and the nest is not reused, so a nest found after the hard frosts is usually empty. A queen seen alone in spring can simply be left to move on or, if she is building on your door frame, the tiny nest can be dealt with before workers appear.

None of the sources we checked reports that bald-faced hornets recognise individual people. What they do describe is nest defence: workers repeatedly sting invaders and can squirt venom from the stinger into an intruder's eyes (Wikipedia), and PestWorld says they will attack anyone or anything that invades their space. Being chased again near the same nest reflects where you are, not who you are. Keep your distance, and do not swat at hornets near the nest.

PestWorld says stings hurt, itch and swell for about 24 hours. Get emergency care for trouble breathing, swelling of the face or throat, dizziness, or many stings.

Photograph from a distance with the zoom rather than approaching a nest. For a lone spring queen, a shot from above showing the face and the white abdominal tip, with an object of known size nearby, is enough. InsectLens names the species, and the size and season checks above tell you whether it is the queen.

Research and drafting for this page used AI assistance. Every figure, date and quotation was then checked line by line against the sources listed at the bottom of the page, each of which was opened while writing. Nothing here is a diagnosis or a treatment plan; if a bite, sting or rash worries you, or anyone has trouble breathing or swelling of the face or throat, get medical care straight away.