BUFFALO — You’ve heard of flash mobs? Behold the Mass mob.
Playing off the idea of using social media to summon crowds for parties or mischief, mobs of Buffalo-area Roman Catholics have been filling pews and lifting spirits at some of the city’s original, now often sparsely attended, churches.
It works this way: On a given Sunday, participants attend Mass en masse at a church they’ve picked in an online vote and promoted through Facebook and Twitter.
Visitors experience the architecture, heritage, and spirit of the aging houses of worship, and the churches once again see the numbers they were built for, along with a helpful bump in donations when the collection baskets are passed.
‘‘I call these churches faith enhancers. You can’t help but walk in and feel closer to a higher power,’’ said Christopher Byrd, who hatched the idea in Buffalo last fall and has organized two Mass mobs so far, both of which drew hundreds. He’s heard from other cities about starting their own.
The aim, he said, is to reignite interest, support, and perhaps even membership in older churches that ‘‘kind of fall off the radar screen of people.’’
One such church is Our Lady of Perpetual Help in a neighborhood settled by Irish immigrants along the Buffalo River. The church once brimmed with 800 families when it was dedicated in 1900. Today, fewer than 50 worshippers typically amble into the Gothic-style building for Sunday Mass.
It’s a familiar story among city churches that were built for waves of Polish, German, Irish, and Italian immigrants where congregations have dwindled with the city’s population decline and suburban sprawl. Buffalo’s population is less than half what it was in 1950, when it peaked at 580,000.
‘‘We’re still here,’’ said the Rev. Donald Lutz, who welcomed a crowd of more than 300 on a recent Sunday after Our Lady of Perpetual Help, known to locals as ‘‘Pets,’’ was selected for the Mass mob.
Organizers sought nominations from the public for churches on the Mass mob website and put the top three up for a vote. Online voting has begun for the next mob, planned for March 23.
‘‘It just shows that we are not just one parish, that it’s the whole family of the diocese,” said Lutz, who learned his church had been chosen two weeks before. “We take care of each other.
‘‘And,’’ he added, ‘‘if it helps us pay a few more bills . . . ”
With every pew occupied, later-arriving worshippers stood against the back wall, reminding 88-year-old parishioner Elizabeth Barrett of the way it used to be in the church she has attended since birth, a block from her lifelong home.
‘‘You had to get here very early when I was young, it was so crowded,’’ she said. ‘‘And now there are just a handful.’’
During the sign of peace, Lutz spent several minutes breezing up and down aisles, smiling and shaking hands. He invited all to a nearby community center for a pastry and coffee after the service.
Several visitors arrived at the church with cameras, aiming them at brilliant stained-glass windows imported from Austria, the church’s pride and joy, and the ornate marble altar, the likes of which are seldom seen in more modern suburban churches.
The eight-county Diocese of Buffalo, in a restructuring, has closed nearly 100 churches in recent years as attendance and financial support have declined and priests have retired. Days after the Mass mob came an announcement that 10 suburban Catholic schools would close after this school year.
Byrd, 46, plans about six Buffalo Mass mobs a year.
Byrd, an activist in the Broadway-Fillmore neighborhood where he grew up, said there has been interest from other cities, and he hopes the flash mob social media hook will resonate with a younger generation for whom the pull of family tradition has relaxed.
“They may think it’s cool,” he said.