ROCHESTER, N.Y. (WROC) — The City of Rochester, along U.S. Department of Agriculture, worked Tuesday to disperse winter roosts of crows in the city.

The work started at dusk, and is set to continue throughout the night. According to USDA, crow roosts in Rochester house 20,000 to 30,000 birds. They say if these crow nests are dispersed, the crows will spread out, and create less mess and damage to the city.

The dispersion methods include “pyrotechnics, spotlights, lasers and amplified electronic recordings of crow distress calls.”

They say no birds will be harmed during this process.