Birdwatchers are everywhere. They’re flocking to sanctuaries and sewage swamps, lagoons and landfills, in search of warblers, whistling ducks, saw-whet owls and peregrines.

They’re not just middle-aged men in field socks; now it’s iPod-toting teenagers, white-haired grandmas: up to 80 million Americans are answering the call to watch birds.

It’s a 400-year-old pastime, but today, with climate change and urban sprawl, bird species are on the decline. Hummingbirds and ravens are feeling the heat.

This hour, On Point: Birds, and the future of bird watching in America.

-Jayne Clayson

Guests:

Scott Weidensaul, naturalist and birder, author of the new book, “Of a Feather: A Brief History of American Birding.”

Kenn Kaufman, author and illustrator for the “Kaufman Field Guide to Birds of North America.”