SAN LUIS OBISPO, Calif. (AP) — An energy company says a so-called “avian incident” is responsible for a fire that cut 84% of the overall generating capacity at one of the largest solar farms in California.

A regulatory filing Wednesday by Clearway Energy says the blaze caused up to $9 million worth of damage on about 1,200 acres (485 hectares) of the California Valley Solar Ranch in San Luis Obispo County.

The filing says distribution poles and cabling will need to be repaired, but no solar panels were damaged.

The report didn’t specify how the June 5 incident occurred or say what exactly an “avian incident” is. An email to the company seeking comment wasn’t immediately returned Thursday.

Clearway says full operations are expected to resume July 1 at the 4,700-acre (1,902-hectare) solar farm on California’s central coast.