A gloop of bird poop was responsible for shutting down the Indian Point nuclear plant for a few hours last December, according to a state-commissioned report into the incident.

The Westchester power plant automatically shut down on Dec. 14, 2015 when a string of dropping from a “large bird” fell into some of the plant’s electrical equipment and caused the reactor’s automatic shut down to trip, according to findings by Entergy, the company that runs the plant.

“Damage was caused by a bird streamer. Streamers are long streams of excrement from large birds that are often expelled as a bird takes off from a perch,”company officials said in the report, ordered by Gov. Cuomo.

“If a streamer contacts an energized conductor, the electrical current may travel through the streamer back to the bird or pole/transmission tower. The result may be a bird electrocution, power outage, and/or line trip.”

Last December’s unplanned shut down was the 13th since June 2012.

It’s not clear how many of those were due to birds, but the dropping did not put the plant in any danger of causing harm to the public, the report said.