When Birch stumbles across Bone in the woods, their mutual excitement over meeting one another is what seals the deal.
spring, year one
Bone watches with a sad whine as over half the pack leaves in a mass exodus, his hunting party abandoning him. He misses them less with each passing day, and will eventually forget.
summer, year one
Bone trains his first apprentice, and feels the thrill of importance. Birch tells him personally that he's earned a place at his side, but Bone politely declines. He stays because he loves Birch, but admits to his face that Birch has changed a lot since they met in the winter. Birch was just starting out, so excited to be chosen as an alpha, as a leader. Bone knows why Fern is drifting away from Birch, and he sees why his loyalty has earned him the offer of being Birch's companion, but he points out how dedicated Horizon is to the position and how well he's doing.
Bone wonders to himself if Horizon knows his status was being discussed in such a way. Sometimes he forgets that he is nearly half of a year Birch's senior. He tells himself that everything is going to be okay.
Hunter 
Hunter