At the Lyndhurst Homing Pigeon Club, it is said that all members are friends until race day. That’s when bragging rights and the potential for thousands of dollars in prize money unleash a fierce competitive streak.

And on a recent Saturday night, the first race of a new season was hours away.

Joe Esteves, the club’s president, toted a crate holding 25 pigeons into the clubhouse on the outskirts of the working-class township of Lyndhurst, N.J., 11 miles west of Manhattan.

Each of the birds had been raised from birth for the obscure yet centuries-old pastime of pigeon racing. And while the first race of the pigeons’ lives would be a 100-mile sprint, the margin of victory could be a matter of seconds.

Mr. Esteves, a 42-year-old father of four, was late. The room had already filled with the easy chatter of longtime club members and an undercurrent of unspoken, competitive grudges.

Similar scenes were playing out that night in the more than two dozen homing pigeon clubs that still operate in New Jersey.