The bald-faced hornet, also known as the white-faced hornet, is a large black wasp with white markings. They range in size from 5/8-3/4+” long. This species is widespread and found in most of the contiguous United States, Alaska, and Canada.
Bald-faced hornets are social insects which live in aerial nests. Their nests are grey, inverted pear-shaped paper nests and they build their nests above ground among the leafy branches of trees, shrubs, and under eaves of buildings. They can exceed two feet in length by summer’s end.
They scavenge in trash receptacles and forage on food and beverages consumed outdoors. They also consume ripe fruit in gardens, farms, and vineyards. In the autumn, the combination of cooler temperatures and reduced food stimulates newly emerged reproductive wasps to seek warm shelter and they are then likely to invade human structures. Colonies of these wasps are most obvious in the late summer and fall when colony numbers have peaked.
Bald-faced hornets are beneficial insects by helping to control many pest insect species. However, if the nest is located close to the ground and near an occupied structure or recreational area, then control is warranted.