Bald-faced hornets are not true hornets but a large species of aerial yellowjacket (Dolichovespula maculata), recognizable by their black bodies and ivory-white facial markings. These highly social insects organize their lives around an annual cycle, meaning colonies begin and end within a single season. The large paper nests they construct are temporary structures that reach peak size in late summer. The colony’s survival during colder months depends entirely on a single, newly produced generation of females.
The Colony Disbands
As temperatures drop in late fall, the colony’s life quickly ends. The original queen, who started the colony in the spring, ceases egg production and soon dies. Worker activity slows as they stop foraging for food and materials. The community’s purpose shifts to producing the next generation of reproductive individuals.
In the final weeks, the queen lays eggs that develop into new males and future queens. Once these new queens and males emerge, they leave the nest to mate; the males die shortly after. The remaining workers and the old queen cannot survive sustained cold weather. The first hard frost accelerates the death of these non-reproductive members, leaving the nest empty.
The Queen’s Hibernation Location
The only members surviving winter are the newly fertilized queens, which are genetically programmed to endure the cold. These queens enter diapause, a state of metabolic slowdown distinct from simple hibernation. Diapause allows the insect to survive for months without food or water by conserving energy and producing cryoprotectant compounds.
Each fertilized queen acts alone, seeking a solitary, sheltered location away from the abandoned nest. They search for spots offering insulation and protection from moisture and temperature fluctuations.
Overwintering Sites
Common overwintering sites include protected crevices under the loose bark of dead trees or inside rotting logs and stumps. They may also burrow into soft soil or leaf litter at the base of trees for thermal protection. Occasionally, queens seek shelter inside man-made structures, finding refuge in unheated attics, sheds, or wall voids.
The queen must remain undisturbed throughout the winter. When spring arrives and the weather warms, she emerges to begin the cycle anew by founding her own colony.
Why the Nest Is Never Reused
The structure that housed the colony all summer will not be occupied again by any bald-faced hornet. The paper-pulp material, constructed from chewed wood fibers and saliva, is not durable enough to withstand a full winter season. Exposure to rain, wind, and snow causes the material to quickly deteriorate, making the nest structurally unsound.
Furthermore, the abandoned structure contains remnants of dead larvae and workers, presenting a biological risk. Pathogens, parasites, and mold spores accumulate within the paper cells, making the site undesirable for a new queen. The new queen is instinctually driven to start a fresh, sterile nest in a new location to ensure the health and success of her emerging colony.