Niall Doherty likes to lug a lightweight, fold-up aluminum stool with him, the kind he can sling over his shoulder, when he heads into the forest to photograph birds.

“It’s very hard to stand still for long periods of time, waiting for a bird to cooperate,” said the 70-year-old North Stonington resident. “But if I can sit down, then I can wait a lot longer, and things happen if you wait,” he said.

A retired Pfizer researcher, Doherty goes into the woods almost every day. After spending a lifetime working with inflammatory diseases, he now devotes almost every waking moment to photographing, in exquisite detail, tiny, hard-to-capture, migratory songbirds, like the elegant blue-winged warbler or black-and-white warbler.

What’s the attraction for Doherty?

“If you ever get a chance to hold a bird in your hand, I once held a ruby-crowned kinglet, there’s almost nothing there. They’re fragile, and yet they travel vast distances and survive in a hostile world,” he said.

When I caught up with the photographer, he had just come back from an outing.

“The woods have been exploding with warblers in the last couple of days,” Doherty said. He was excited about a phenomenon that causes bird lovers of all stripes to grab their binoculars and guidebooks and head to popular places like Bluff Point State Park or Avery Farms Nature Preserve to view the spectacle.

I asked Maggie Jones, former executive director of Denison Pequotsepos Nature Center and birder extraordinaire, to explain why the forests around us “explode” with warblers in early May. This was her explanation.

“The birds are moving to their northern breeding ground with a sense of urgency to find a mate, build a nest and raise a family. They have one chance, time for just one brood (unlike chickadees, cardinals and other year-round resident birds) before starting their journey back to the tropics later in the summer. Many of these migrants nest in the boreal forest of the northern U.S. and Canada, and we may be lucky enough to spot them fueling and resting in southern New England,” Jones said.

To capture his subjects up close, Doherty uses a Panasonic Lumix G9 camera, with a 100-400 mm detachable zoom lens, retailing for about $1,200.

“It’s not the most powerful camera, but it’s a nice combination of power, weight and size,” he said.

What are some of Doherty’s favorite birds to photograph? He said he is partial to the indigo bunting, a small songbird with a deep, rich color all over.

“It’s a spectacular blue. When the sun shines on it, it out-blues a blue bird,” he said, adding, “I think all birds are beautiful, wonderful, and so well adapted to survival.”

Bill Hobbs lives in Stonington. He can be reached at whobbs246@gmail.com.