The family in the Los Angeles suburb came home from dinner to find their house had been invaded by an enormous flock of chimney swifts.
And the birds, who pass by the region on their annual migration, swarmed around the house and made their way in down the chimney.
The birds then refused to leave the property when the owners opened all of the windows and doors.
“It’s so hard to explain. If you don’t see it with your own eyes, you’d never believe it,” the homeowner, who gave her name as Kerri, told KTLA.
“We lost count after 800,” Kerri said.
She added that the family, who had to spend the night in a hotel, took two days to clean up all the bird poop.
Chimney swifts are known for roosting overnight in chimneys, in groups of hundreds or thousands, before and during their migration.
The birds are protected by the federal Migratory Bird Treaty Act and cannot be legally removed from a chimney.
They arrive in the US in March and leave again by November, and nesting normally takes place between May and August.
Unlike most birds they do not sit on perches or branches, as their claws are only suited to clinging onto vertical surfaces such as chimneys.
Home owners have been advised to close their chimney vents during the season.