The air hums more than usual on Thursday evenings at the Wicked Oyster in Wellfleet. From 6 to 8 p.m., the Volunteers, a small jazz combo, occupies one low-lit corner. There’s Andrew Staker, front and center, blowing smooth melodies on his saxophone; Alex Hay, tapping and swishing his drum set; Asa Nadeau in the back, meandering through chord progressions on his guitar; and Rod McCaulley, leaning on his double bass, buoying the band with his firm pizzicato.

“We know ourselves as the house band,” says Staker, who lives in Wellfleet and teaches music at Wellfleet Elementary School. Nadeau lives in Orleans, where he grew up, and works in consulting. McCaulley — Nadeau calls him “the venerable Rod McCaulley,” and “Lightning Rod” — is a professional musician who lives in South Yarmouth and drives up to Wellfleet every Thursday for the gig. Hay lives in Wellfleet and owns the Wellfleet Shellfish Company. He bought the Wicked Oyster restaurant on Main Street with Garrett Smythe and Sebastien Taffara last spring.

The four don’t rehearse outside of their regular Thursday gigs, says Nadeau. They just arrive, unpack their cases, warm up their fingers (or lips), and play. That improvisational spirit is an essential part of jazz, Nadeau says: you show up and you’ve got to know your stuff.

Nadeau studied with a local jazz guitarist, Fred Fried, who told Nadeau that he’d played gigs where the musician calling a tune wouldn’t announce to the rest of the band what key it was in — he’d just throw up three fingers, signaling the number of flats.

Many jazz standards are stored in the hands of the Volunteers already. They’ll play “hard bop, cool jazz, trad jazz, Latin, some bebop,” says Staker, who grew up on jazz and plays several instruments. Sometimes Nadeau will persuade them to play reggae. For unfamiliar tunes — they play two or three new tunes every week — Staker will sight-read the head (the melody), and the band will follow fearlessly.

“It’s kind of like, if you can drive a small boat, you can drive a bigger boat,” says Nadeau. “We are not afraid.”

The Volunteers got their name when Hay participated as a “parent volunteer” drummer in Staker’s elementary school band. The two began to play with each other outside of school. Hay and Nadeau, whose daughters are the same age, have known each other from childhood.

“My parents and Alex’s parents hung out in the ’70s,” says Nadeau, “doing whatever they did back then — riding motorcycles barefoot.” Hay recruited Nadeau for what was fast becoming a “real band,” says Staker. They had “transient” bassists for a while until they found McCaulley.

At the Wicked Oyster, Staker lifts the reed to his mouth. Behind him, Nadeau’s fingers alight on the right strings. Eyes glance, heads nod. The band’s communication is quick and intuitive. They haven’t yet started the next tune — the buzz of diners’ conversations has risen to fill the room —  but it’s as if the music has already begun, and they’re listening to it, waiting for the right moment to join in. When they begin to play, the room seems to grow warmer.

When performing in such a small space, says Staker, it’s important for the band to read the room. “At any point we could hit a note that’s too loud,” he says. “Then we might pick up on a little wince here and there.” More important than negative reactions are the positive ones. The room is content, says Staker, “when the general aura of sound matches the music. You’ll notice people clinking glasses and chatting. Or maybe they’re alone and rocking back and forth.”

Though their hands are busy, all four members of the band make sure to read each other, too. Each will take a solo in turn, improvising an elaboration over the harmonic progression of a tune. Nadeau has learned to recognize when Staker is finishing his solo: the saxophone gets louder as Staker turns around to face Nadeau and invite the band back in. McCaulley, who knows hundreds of tunes from memory, is especially good at signaling the path of his solos — where they’ll reach an apex and what note they’ll end on.

“He knows where he’s going,” says Nadeau. The room usually applauds when he’s done.

“The main skill is knowing where you are,” says Staker. When Hay takes a solo on the drums, he’ll hear the melody in his head as he strokes and kicks a rhythm. Sometimes an audience member will want to talk with Staker during another band member’s solo. But a part of him is listening to the chords in progress, tracking the measures.

When a song ends, the band might draw it out in an improvised fermata. “You have to do that with your body,” says Staker. “It’s a lot like conducting.”

To play for an audience without rehearsal requires a certain confidence. Staker says that over their years together the band’s confidence has only grown. That doesn’t mean they don’t occasionally make a mistake. But jazz is forgiving. Nadeau learned this from another jazz musician: “You can play the wrong note at the right time, but not the right note at the wrong time.” The key is not to interrupt the rhythmic flow. “We’ve gotten to a point where we rarely drop the beat,” says Staker.

“You practice like you play,” says Nadeau. “My soccer coach used to say that.” These Thursday gigs are “live improvisational practice where mistakes become a part of the tapestry of the performance. Sometimes it’s funny, sometimes it’s frustrating, and sometimes it’s awesome.”

Outside of Thursday nights, the band doesn’t see each other very much. “We have separate lives,” says Nadeau. “The depth of our relationship has evolved from these gigs.” Everyone is busy, he says. To count on the band to show up every week requires “a level of trust.”

“It’s our favorite time of the week,” says Staker. “The exercise is to be as present as possible. It’s not how many notes you can put into a solo, it’s how authentically you are there.”

The Volunteers played at Wellfleet’s Fox & Crow every Thursday from its first week until it closed in the fall of 2023 — a period that Staker calls “a beautiful flare-up of awesomeness.” When Hay and his partners bought the Wicked Oyster, he guaranteed the Volunteers, who were suddenly adrift, a spot. In a town like Wellfleet, “whatever you want to exist,” says Staker, “you have to make it exist.”

The space feels familiar to them. “This is our community,” says Staker. Paintings by Nadeau’s mother, Rosalie Nadeau, decorate the walls of main dining room, which is visible through a narrow doorway from the band’s corner. The band members’ kids wander in and out of the room. “We feel comfortable enough to let our guard down, to be part of the background.”

Here, awash in warm candlelight, and not far from the tavern where they first made Thursday nights their own, “It feels like we’re home,” says Staker.