Cluster Flies
The slow, clumsy flies that pile up in sunny windows on warm winter days.
Where they thrive
Lawns and parks in summer. Attics, top floors and south-facing walls in fall and winter.
How they behave
Slower and clumsier than house flies, wings overlapping at rest. They pile up in sunny windows.
In New York City
Buildings next to parks and lawns see them on warm winter days, buzzing at the glass.
Did you know?
Their larvae are earthworm parasites. They hatch in soil and burrow into worms.
Related pests
Yellow Jackets and Wasps
Late summer's uninvited guests at outdoor dining, trash corrals and anywhere sugar sits out.
Read more →Carpenter Ants
The biggest ants in New York, carving tunnels through damp wood in brownstones and older buildings.
Read more →Stink Bugs
An East Asian invader that gathers on sunny walls each fall and slips inside to spend the winter.
Read more →Think you have Cluster Flies?
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