When they migrate to the Pacific Northwest in the summer, purple martins rely on human-made structures for their nesting sites. The Tacoma Parks Department maintains some of the boxes, and it seems they're being used. NWPB's Lauren Gallop reports.

Down at the Point Defiance Marina in Tacoma, people are seeing purple martin chicks. That's proof that the nesting boxes the zoo put up a little over a year ago are attracting the migrating birds. Zachary Hahn is the conservation program coordinator for Point Defiance Zoo and Aquarium. 

He says since people have been putting up more nesting sites for the birds, we're seeing more of them in the South Sound. Without the boxes, the birds wouldn't be having as much of a recovery in the region. As we walk along the boardwalk, Hahn gets out his binoculars and asks his colleague to take a look.

Sam, who is this? Hello? Yeah, that's a purple martin. Yep. These birds have dark bluish purple feathers. 

They have blunt tails and are bigger than other swallows. Right now, the adult purple martins are foraging for large insects to feed their chicks. The birds swoop down to the nesting sites to feed, then back up into the sky to collect more food.

They'll do this until their babies are ready for migration this fall all the way to South America. In Tacoma, I'm Lauren Gallop.