If you’re sailing down the Willamette River through Corvallis, don’t be surprised when you hear distant piano music. No, it’s not some river ghost — it’s probably the Barker Gypsies.

For the past three summers, the folk-pop duo of singer Catherine Ellis and keyboardist Brian Poucher has claimed a sandbar just offshore from their hometown’s Willamette Park and Natural Area as their base, playing for river-floaters and landlubbers alike.

“People can hear us before they see us,” Ellis says.

They used to perform weekly, but as they’ve played more and more gigs outside of Corvallis (Ellis is in another band, Parish Gap, which performs at the Embers in Eugene July 23), they’ve shifted to a monthly schedule. The Gypsies’ next island set is 1 to 4:30 pm Sunday, July 31, followed by another session Sept. 4.

The Barker Gypsies have a repertoire of at least 30 songs, mostly covers but also some originals. They rarely predetermine which songs they’ll play before hauling their equipment out on a motorboat to the island, and the vocal-keyboard setup affords plenty of freedom with their setlist.

“If we feel like playing a song twice, we do it,” Ellis says.

In addition to music, the Barker Gypsies also provide art supplies for locals to participate in their People’s Map of Corvallis project, an interactive digital map of Corvallis they hope to someday turn into an app. Participants are asked to draw their memories of specific spots in Corvallis, then assign them to locations on the map.

“Someone might want to draw a pic of their university, their first dorm,” Poucher says. “But we say you don’t have to draw just a dorm, you can draw something that happened there, like meeting your best friend. It’s a collective history expressed in a new way.”

So far, nobody’s complained about these bohos taking over a whole island for their music and art project.

“When we first started three years ago, we asked the police, the county park department, the city department,” Ellis says of seeking permission. Everyone just shrugged.

“That’s the kind of town Corvallis is,” says Poucher, citing a recent proliferation of public pianos around town as evidence of his hometown’s openness towards public art and performance.

According to the band, those on the river are usually delighted to see them. Some people even sing along to their covers — a favorite being “Come Sail Away” by Styx.

“They’re floating!” Ellis says. “They want to sing ‘Come sail away/ Come sail away with me!’”

For more info, visit islandmusic.co.