I recently did a story that got more listener comments than any other I’ve done in a while. It was about this mysterious noise I heard at my house early one recent morning.


PFEIFFER: A loud, metallic hammering over and over.


PFEIFFER: It turned out to be a woodpecker hammering on my rooftop metal chimney cap. So I decided to find out why a bird would do that. And my story explaining that animal behavior got a lot of responses from people who had the same startling experience.

VAL MINA: My wife and I - we were looking at each other like, what the heck is happening? Like, there was a time of short panic. And it was a bird hammering away at the side of our chimney, making this super-mechanical sound.

NICK ONIDAS: If you take a garbage can lid and screwdriver and just rap on the garbage can lid rapidly - you know, bang, bang, bang, bang, bang - it’s kind of like that.

JUSTINE MATHERINE: It did not sound like a beak hitting wood. It sounded like really loud metal tapping.

THOMAS GRILLO: I guess it would be like if you were banging a nail into metal. And my neighbor came out and said, what is that noise?

PFEIFFER: Those were NPR listeners Val Mina (ph), Nick Onidas (ph), Justine Matherine (ph) and Thomas Grillo (ph). I also heard from a very familiar voice to this show.

MELISSA BLOCK, BYLINE: This is Melissa Block. I’m a longtime NPR correspondent and former ALL THINGS CONSIDERED host.

PFEIFFER: Melissa told me she’s had this happen at her house, too.

BLOCK: It was so loud. It felt almost like the whole house was shaking, like, metallic, jackhammer-like, prolonged period of time.

PFEIFFER: And I heard from 84-year-old John Stott (ph). He said my story answered a question he’s had since the late 1980s. Back then, he was at his cabin in Michigan when he was jarred out of sleep.

JOHN STOTT: It was about 6 o’clock in the morning, and then rat-tat-tat-tat-tat started occurring just as daybreak came along. And I didn’t know what was happening.

PFEIFFER: His metal stovepipe seemed to be reverberating. So...

STOTT: I went outside, and there was this darn woodpecker, not being a woodpecker but being a metal chimney pecker, as it were.

PFEIFFER: He shooed the bird away by tossing a pine cone at it and later told his neighbors what had happened.

STOTT: One of them wondered if I’d had too many beers before I went to bed the night before. And others said, oh, well, that’s the way they clean their beaks or sharpen their bills.

PFEIFFER: But that is not why woodpeckers hammer on metal. I know that because I asked Kevin McGowan of the Cornell Lab of Ornithology. He said woodpeckers hammer on wood to find food, make a home, mark territory and attract mates. But when they bash away at metal...

KEVIN MCGOWAN: What the birds are trying to do is make as big a noise as possible, and a number of these guys have found that - you know what? - if you hammer on metal, it’s really loud.

PFEIFFER: So they’ll drill on chimney caps, vent pipes, gutters, aluminum siding, traffic signs, even satellite dishes. And that metallic racket sends two messages.

MCGOWAN: All other guys, stay away. All the girls, come to me.

PFEIFFER: When John Stott heard my story, he finally had an explanation for something he’d been wondering for 35 years.

STOTT: This was an unsolved mystery, and nobody knew what it was about, and there you were for me.

PFEIFFER: That’s what we try to do at NPR because, after all, we are ALL THINGS CONSIDERED.

(SOUNDBITE OF KACEY MUSGRAVES SONG, “OH, WHAT A WORLD”) Transcript provided by NPR, Copyright NPR.