Cooperative Extension source for BDN piece on cluster flies
A University of Maine Cooperative Extension fact sheet co-authored by Griffin Dill, pest management specialist with Cooperative Extension, and Clay A. Kirby, insect diagnostician, was referenced in a Bangor Daily News article about cluster flies. Cluster flies look like house flies but are larger, with yellowish hairs on the thorax. During late summer, they amass, or cluster, behind household siding and cracks and crevices in attics. They often become apparent in the winter when a previously cold room is heated. According to Dill’s fact sheet, cluster flies are generally not noticed in the summer when they’re searching for earthworm hosts. According to the fact sheet, cluster flies do not bite and aren’t attracted to garbage. They are a good indication of a nearby earthworms.