Bald-faced hornets (Dolichovespula maculata) are not true hornets, but rather a species of aerial yellowjacket, a type of social wasp found across North America. The entire seasonal colony, which can contain up to 700 individuals by late summer, operates on a single-year cycle, meaning the vast majority of the population does not survive the transition into winter. Understanding the fate of the colony and its queens is the answer to where these insects go when the weather turns cold.
The End of the Hornet Colony
The onset of colder temperatures and resource scarcity in late fall marks the end for the majority of the bald-faced hornet population. The thousands of sterile female workers and the short-lived males produced late in the season are annual insects whose lifecycles are tied to the warmth of the summer months. Once the first hard frost arrives, or food sources become too scarce to maintain the colony, these individuals begin to die off completely.
The workers and the males do not hibernate. Their metabolisms are not equipped to survive extended periods of freezing temperatures or lack of food. The former queen, who started the nest in the spring, also perishes around this time, concluding her reproductive cycle. The colony’s function ceases entirely as the worker population dwindles, leaving the nest empty and inactive by the time deep winter sets in.
The Queen’s Winter Survival Strategy
Survival of the species rests entirely on the newly fertilized queens produced in late summer or early fall. These females leave the nest to mate and immediately begin preparing for the cold months ahead. Before winter, the young queens engage in heavy feeding to build up substantial fat reserves, which serve as their primary energy source during overwintering.
These fertilized females then seek out a suitable hibernaculum, a sheltered location offering protection from the elements and temperature fluctuations. Common overwintering sites include protected crevices beneath loose tree bark, inside rotting logs, or buried beneath the soil line. Queens may also find shelter in human-made structures, such as within wall voids, under eaves, or inside sheds. Once settled, the queen enters diapause, a state of metabolic suspension that dramatically lowers her body’s energy consumption, allowing her to survive the winter without food until spring prompts her emergence to start a new colony.
The Fate of the Paper Nest
The large, gray, football-shaped structure constructed by the bald-faced hornets is an annual structure that is never reused. This aerial nest is built from a mixture of chewed wood fibers and saliva, which dries into a light, paper-like material. Because the nest is made from wood pulp, it is not designed to withstand the full degradation of a harsh winter season.
Once the colony dies off, the nest is structurally abandoned and poses no further threat. The paper material will begin to naturally degrade and become tattered over the winter months due to moisture and wind. Homeowners can safely remove the structure in mid-to-late winter, typically after a prolonged period of freezing temperatures, ensuring all inhabitants have perished. This removal is simply for aesthetics, as the empty nest is not a functional home for any future bald-faced hornets.