The bald-faced hornet is actually more closely related to yellow jackets then hornets. They get the term hornet because they build their nests above ground and due to their large size. Bald-faced hornets are found throughout the United States and up into Canada. More common in the southeastern United States, they are recognizable by their large grey football shaped nest.
Adult workers are about 2/3 of an inch long while queens can be as large as 1 1/8 inches long. Most of their body is black but they do have a white face which is why they are also known as white-faced hornets. Nests can be three feet tall and bald-faced hornets will sting repeatedly if threatened.
Fertilized queens are the only members that over winter in protected areas. In the spring, they choose a nest location, usually in wooded areas or in good leaf cover. The female then starts to build a nest out of cellulose material into a carton structure. The female lays a batch of eggs with one egg to a cell and feeds the developing larvae nectar and chewed up insects. After 30 days, the first workers emerge and take over the nest building. By the end of the fall, the nest is entering the declining stage where all but the newly inseminated queens die.
Nests are often not noticed until leaves begin to fall later in the year. Management is usually not necessary if the nest is high in a tree though avoidance is recommended. Agricultural inspectors consider bald-faced hornets a beneficial insect as they feed on many pest species. However, if a nest is low to the ground or in a highly populated area, a professional should be called in for removal.
Bald-faced hornets are usually only aggressive when threatened. Children should not be allowed to throw objects at the nests. Unlike honeybees, bald-faced hornets are capable of stinging repeatedly.