Stafford shopping plaza hosts up to 500,000 birds each sunset in summertime display

STAFFORD, Texas (KTRK) -- At a shopping center in Stafford, it wasn't the steep sales that brought out families Monday night. It was the birds.

They are purple martins, to be exact. Thousands of them are roosting in trees outside an Old Navy store. They swirled through the air around sunset.

Ben Griffin and Janna Skinner came out to see for themselves the sight they'd heard about from their families.

"They said it's a really cool thing to see, just all the, like, hundreds of thousands of birds swarming around," Griffin said.

The Houston Audubon Society indicates the birds are hanging out preparing to migrate.

The numbers are so great, and the flock so dense, they can even pop up on weather tracking systems.

"It's really cool and I've never seen anything like this before," Skinner said.

They're expected to be there for the next couple of weeks before continuing on their migratory route.