This large, black-and-white Yellowjacket gets its common name of Baldfaced from its largely black body but mostly white face, and that of Hornet because of its much larger size as well as aerial nest.
Baldfaced Hornets are found throughout the United States. Adult worker Baldfaced Hornets are typically 3/4″ long, but can be up to 1” long, their body is mostly black with a white face and also white on the tail of their abdomen.
Baldfaced Hornets are social insects which live in aerial nests. Only the new Baldfaced Hornet queens overwinter and do so in sheltered places such as under logs or stumps, but often in attics as well. In the spring, the queen uses chewed-up cellulose to build a paper carton nest of several dozen cells covered by a paper envelope. One egg is laid in each cell as it is constructed and the queen feeds the developing larvae protein from insect prey and nectar. After about 30 days, the first 5-7 workers emerge and take over all the work except the egg laying. The nest will eventually consist of 3-5 layers of rounded paper combs and are covered by a many-layered envelope. Baldfaced Hornet nests vary in size but typically have less than 2,000 cells in the nest and between 100 to 400 adult workers. Later in the season, reproductive females and males are hatched to mate so the new queens can overwinter. The founding queen, the workers and the males all die at the end of every season.
Baldfaced Hornet nest sites can vary from shrubs or vines at ground level up to 60ft or higher in trees. Nests may also be built on overhangs, utility poles, houses, sheds or other structures, but nearly all nests are constructed in exposed locations. At maturity, the nests can be quite impressive with sizes often reaching 14” in diameter and over 24” in length. Often, nests located in vegetation are not discovered until the leaves fall in autumn. Baldfaced Hornet nests are never reused the next season.
Hornets are considered beneficial insects because their food consists mostly of other insects, often spiders or other pest species. However, if the Yellowjacket nest is located close to an occupied building or recreational area, then control is needed. Treatment for Baldfaced Hornets consists of spraying the nest with an appropriate pesticide and removal of nest, which should be done by a trained and licensed pest control operator.