Boko Haram’s first target was Mai Ajirambe, an elderly leader of the hunters’ group. Insurgents tracked him to a village near his home and kidnapped him. When fellow hunters found Mr. Ajirambe, he had been decapitated, his head carefully placed on his back.

“We decided right then, they won’t stop until they kill all of us,” Mr. Bukar said.

He and other hunters gathered their families and moved them from their rural villages to the state capital, Maiduguri, for safety. Then they joined the fight. Now, the hunters sometimes lead soldiers into battle with their own homemade, long-barreled guns.

Like most hunters, they brag about their successes and lament the ones that got away.

One of Mr. Bukar’s biggest regrets came on the day that he and the soldiers found the first girl from Chibok. He said he caught a fighter and delivered him to the soldiers, but then the man somehow escaped in all the excitement of finding one of the kidnapped students.

While last weekend’s liberation of the Chibok schoolgirls is a victory, Mr. Bukar knows the hunt for Boko Haram fighters is far from finished.

When Mr. Bukar gets ready for a mission, he follows the same routine he has used since boyhood. He rubs an herbal mix across his body to mask his scent. He puts on his lucky necklace. In the field, he stays as quiet as possible, relying on hand signals to communicate with fellow hunters. He never runs after his prey; he lets it come to him.

“Once you meet it, there are only two options: You kill it or it kills you,” Mr. Bukar said.

The hunters are relying on traditions handed down through generations. Many began hunting when they were young boys, heading to the bush with uncles, fathers and grandfathers. A handful of women who hunt have also joined the Boko Haram fight.