European Hornet (Vespa crabro)

Habits:

Although typically active during the daytime, European Hornet workers may fly at night in humid, windless conditions and are attracted to external lighting and windowpanes. European Hornets have an exceptionally long seasonal cycle, reproducing from late August through November. Workers prey on a variety of insects -- including grasshoppers and other orthopterans, flies, honeybees and yellowjackets -- to feed their larvae. Hornets can also "girdle" a variety of trees for sap, including ash, lilac, horse chestnut, dogwood, dahlia, rhododendron, boxwood, and birch -- which may result in the death of the tree. Colonies last for one year.

Nests:

European Hornet nests are typically built in hollow trees, but can be found in barns, sheds, attics and wall voids in buildings. Frequently, the nests are built in the openings of protected cavities. Nests built in wall voids may emit a stench. Mature nests have 300-500 workers, and can occasionally number up to 1,000.

Nature toward humans:

European Hornets are not typically aggressive unless handled, or the colony is threatened.  Though the European Hornet prefers forested areas to urban settings, many suburban homes in the U.S. are located near these wooded habitats, which increases the likelihood of human contact.

Bald-faced Hornet

Paper Wasps

Yellowjackets