The outside of the exposed nest will be covered with coarse, thick, tan, paper-like material fashioned from decayed wood fibers. Nests built in wall voids may emit a noticeable stench. In the spring, individual hornet queens emerge from hibernation and begin nest building . Once a queen has produced enough workers to take over this duty, she remains inside the nest producing more offspring. Their diet consists mainly of large insects such grasshoppers, flies, bees, and yellow jackets.
European hornets have a long seasonal cycle.
These reproductives mate and the females will serve as the next generation of queens in the following spring. As winter approaches, the workers die off. The future queens abandon the nest and seek out shelter in protected places, such as under loose bark, in rotting stumps, and hollow. Although the queens overwinter individually, you may find large numbers of them using the same hibernation site. The abandoned nests are not reused next year.