Archives for cluster flies

The Nature of Phenology 9/8/18

Producers/Hosts: Hazel Stark and Joe Horn

Cluster Flies

Photos, a full transcript, references, contact information, and more available at

Cluster flies are a non-native member of the blow fly family who, contrary to their persistence indoors, will not actually reproduce in home or office, but rather are simply looking for a warm sunny window upon which they can persist through the cold winter months of the New World. They are larger than houseflies, hairier, slower, much less coordinated in flight, and of course amass in their iconic numbers. In fact, cluster flies are their very own species called Pollenia rudis and they certainly are the rudest guests I have ever hosted!