Falconry couple keeping pigeons out of downtown Detroit

How it works: Thomas and his wife demonstrated their practice by walking toward a flock of pigeons playing a distress call and showing them the hawk, which flaps its wings while perched on its handler.

What they're saying: "It's kind of like when you go to the beach and people yell 'shark, shark!'" Thomas says. "About 10,000 starlings were nesting on this building a couple weeks ago before we got here."

• "They would poop down the side and they were power washing it but two days later it looked like nothing was done. You'd have 3 inches of poop on the sidewalks."

Bottom line: Thomas says it takes about a month for pigeons to learn they aren't welcome and stop returning.