Bald-faced hornets are more closely related to yellow jackets than they are to hornets. The body of the bald-faced hornet is black in color, and its face is marked with white. Bald-faced hornets are larger than most yellow jackets, with workers ranging from 15 to 20 mm or more. Bald-faced hornets are most active during the day. They usually build aerial nests made of paper in trees or under overhangs. Adults consume liquids, usually sugars like juices or nectar, but will bring back solids such as insects or carrion for the larvae to consume.
The nest of the bald-faced hornet can be found hanging from trees, bushes and buildings. A colony begins in spring, when a queen lays a single egg inside each cell as she begins to build her nest. She puts insects and nectar into the cell with the egg. These eggs hatch into larvae, eventually becoming workers that help to further expand the nest.
A bald-faced hornet nest can grow to be as large as a basketball within a number of months. As many as 700 workers may live in the nest. Males appear late in the summer. The males fertilize some of the newly developed females. These fertilized females look for places to hibernate as cold weather approaches. They will be the next season’s queens. The remaining members of the nest perish in winter.