Purple martins return for their short stay

Hundreds of thousands of purple martins are visiting Houston before their journey down to South America.

What's happening: Every year as summer comes to an end, purple martins come down to Houston from as far north as Michigan to roost and feed on insects to fuel up before their long journey.

• For about a decade, the purple martins have gathered on a row of about eight live oak trees in Willowbrook Plaza from late July to early October, Mary Anne Morris, education director for Houston Audubon, tells Axios.

Driving the news: Houston Audubon is hosting several watch parties.

• The next watch parties are on Aug. 26, Sept. 3 and Sept. 17. Houston Audubon is there to answer questions as well as offer napkins if you are a lucky winner of bird poop.

State of play: About 225,000 birds gather daily in the parking lot right now, but the flock has gotten as large as 500,000 before. Houston Audubon looks at the bird density in the weather radar to approximate the number.

• Some of the groups of birds stay in Houston for a few weeks. And while they're in Houston, they essentially provide the city with pest control.

What they're saying: "It's really special. We're very fortunate to have such a big roost," Morris says. "It's something to celebrate for sure every summer."

Threat level: The hot weather is often detrimental to young birds. Morris says they've had a tough couple of years with longer winters, colder springs, heat and no water.

The intrigue: Houston Audubon gives businesses in the area a "roost alert," but after a decade of this, the businesses know what to expect.

• The Wendy's in the lot has seen more customers in the past two weeks, an employee tells Axios, and servers at El Capitán Seafood & Mexican Grill regularly wipe their patio from bird poop.

👋 Shafaq here! I went to the first watch party this Saturday and was so blown away that I went again Monday evening.

My experience: It was the most magical experience to see thousands of purple martins swirling in the night sky.

• The birds would swarm like a tornado, as if they were dancing.
• At the watch party, close to a hundred spectators gathered to view the phenomenon together. But even on a regular night, there were a handful of families.
• The live oak branches drooped with the weight of the hundreds of birds — and you could hear them all chirping, sounding like a rainstick.

Pro tip: Bring an umbrella and park away from the trees, because the birds do poop a lot, and the pungent smell is strong from feet away.