When Niles dentist David Johnson isn’t searching for cavities, he’s outside searching for birds.

“I’m a bird-watching nut,” said Johnson, who’s been practicing dentistry in Niles since 2005.

Johnson has been bird watching since his early 20s. His goal is to physically see every variety of bird in the United States. He’s seen more than 700 so far.

“The big ‘listers’ have over 800, which is an amazing feat,” he said. “When you get to 700, you’ve seen all the breeding birds, so you can’t easily go and find them anymore — you have to chase after the rare ones.”

To keep track of his bird count, Johnson records each spotting in a book he stores in a safe at his home in Cassopolis.

“I keep it at home locked up so, if there’s a fire, it won’t burn,” he said. “It’s an important book.”

Globe trotter

Johnson has traveled the world in pursuit of his next bird. He’s been to every state in the U.S. and dozens of countries, including Taiwan, Panama, Hong Kong, Israel and Spain to name a few.

He is most proud of a bird he spotted while stationed in Alaska with the U.S. Navy in the late 1960s/early 1970s.

There he got a glimpse of the Eastern Spot Billed Duck. Knowing he had spotted something special, Johnson contacted a birdwatcher at the University of Alaska Fairbanks, which confirmed he was the first person to record seeing the duck in the U.S.

“That was the most exciting one,” he said.

Johnson eyed another prize in the unlikeliest of places — in the yard of his Cassopolis home around five years ago. A Eurasian Tree Sparrow was eating from one of his bird feeders. Johnson’s wife snapped a photo of the bird and sent it to the Michigan Birds Record Committee. It was the first sighting of the bird in Michigan.

“Probably 200 people came to my house over the next two months wanting to see that bird,” he said.

More than a hobby

Johnson’s interest in bird watching began at a golf course in Lancaster, Mass, where he was attending college. There he saw a Rose-breasted Grosbeak sitting in a tree.

“It’s a beautiful bird,” he said. “That’s what triggered it. I said, ‘Wow, I have to see more.’”

Johnson got a book about birds and a cheap pair of binoculars, and hit the countryside.

Johnson’s pursuit of seeing every bird in North America has, at times, bordered on obsessive.

He gets daily updates on bird sightings across the country from his computer.

Many years ago, while in college, Johnson got word that a Green Violetear hummingbird — rarely seen in the U.S. — had been spotted in Austin, Texas.

Johnson rented a car with three of his friends and drove from Massachusetts to Austin, where they spotted the bird.

That was his last impromptu cross-country road trip.

“The anticipation and the frustration if you don’t see it was too much,” he said. “I don’t need that stress.

“I don’t go chasing after them, but that’s how people get over 800.”

Johnson still bird watches today, although not as much as he used to.

His favorite places in Southwest Michigan to see birds include the sewage treatment ponds in Three Oaks and Warren Dunes.

“It’s all about getting out, getting exercise, getting fresh air and seeing something new,” he said.

More information on bird watching in Southwest Michigan can be found at berriencounty.org. Click on the link for Berrien County Parks to find the bird watching section.