Some people are intense birders, spending their vacations chalking up species in Oregon or Scotland or Timbuktu. Some people are obsessive bicyclists, making 100-mile day trips or crossing mountain ranges. And some people are tech geeks, absorbed in new ways to record or quantify or manipulate data.

And then there’s Donald Kroodsma, who combined all three obsessions, plus a few more, into one of the quirkiest and most oddly charming travel books you’re likely to come across. “Listening to a Continent Sing: Birdsong by Bicycle From the Atlantic to the Pacific” is his 300-plus-page chronicle of a 10-week, nearly 5,000-mile bicycle trip he took with his son, David, stopping constantly to listen to and record birds. He includes a lot of geology and history, not to mention meditations on the father-son relationship and what is worth doing in life.

As they take this ride, Donald is 56 and a professor of ornithology at the University of Massachusetts at Amherst, and David is 24, with a freshly minted master’s degree from Stanford. Donald is so fluent in birdsong that he identifies most species by sound, not sight; he rarely pulls out the binoculars. He does the best he can to convey what he hears: alee la-o, ayo alee . . . cooowaah coo coo . . . , bob white! bob white! . . . seet kaSLWEEP pa-TIK . . . tsick-a-dee-dee-dee . . . .

Which for most of us amateurs doesn’t quite get the sound across. But that’s where the tech-geek part comes in: The book’s margins are filled with QR codes that play the songs when you scan them with your smartphone. (Ah, so that’s what he means by kaSLWEEP!) There are 381 of these codes, though not all are birds — at Yellowstone, for example, you can scan three QRs and hear the hissing, bubbling and erupting of geysers.

There’s also a website — at listeningtoacontinentsing.com — where you can sort the recordings by, say, all the owls, or all the swifts and hummingbirds. In the end, the whole package is engagingly chipper, a memoir of delight.