The Carolina wren is one of a number of birds that roost in cavities during the winter. These sites provide the birds with protection from rain, ice, and snow, cold winds, as well as frigid temperatures.
It is well-known fact Carolina wrens roost during the winter in such locations as potting sheds, livestock barns, garages, hanging baskets, bird nesting boxes as well as tree cavities. Remarkably, they also use the abandoned papery nests of bald-faced hornets.
This odd behavior has been documented in at least two states. More than 90 years ago a West Virginia naturalist collected a bald-faced hornet nest and hung it in a shed. Sometime later, he noticed a pair of Carolina wrens had apparently modified the entrance hole of the nest to enable them to easily enter and leave the football-sized nest. He went on to report Carolina wrens used the hornet nest as a winter roost site for the next five years.
A researcher in North Carolina reported that, over the course of a decade, he stored abandoned bald-faced hornet nests beneath a porch. During this period, at least one Carolina wren roosted in the nests each winter.
To my knowledge, this behavior has not been documented in Georgia. If you have witnessed Carolina wrens roosting in a hornet nest in the Peach State, I would love to hear from you.