UPDATE, 9:17 a.m.: Officials with Southern California Edison do not have an estimated time for power to be restored after thousands were left without electricity.
At 7:24 a.m., workers restored power to many of those affected, with only 1,896 still without electricity.
Customers between Sierra Madre Avenue, the Interstate 210 Freeway, San Jose Drive and Grand Avenue were affected, said Robert Villegas with SoCal Edison.
The cause is still being evaluated, but Glendora Police on their social media outlets reported a parrot landing on power lines possibly caused the outage.
PREVIOUS: A large power outage is affecting 2,459 customers around town Tuesday morning.
The outage reportedly occurred at 7 a.m. near East Dalton and South Elwood avenues. Crews are reportedly testing the power lines affected to reduce the number of customers affected, according to the Southern California Edison website.
Glendora Police officers are reporting traffic signals at Cullen Avenue and Foothill Boulevard, as well as Loraine Avenue and Foothill are affected.
Los Angeles County Firefighters are also out on a call of power lines down in the 100 block of West Carroll Avenue.
No further information is available.