He's a Changed Man: Why?

As background, I take care of a feral cat colony, mostly composed of abandoned cats.  In January 2011 a friend converted one of her rooms in her house into a Cattery, where we moved, over a period of three months, four (and recently "Petey") cats from the colony to resocialize them and adopt them out.  Two have been placed into forever homes; two are ready to be adopted out.  "Mystique" is still a work in progress.

"Buckley" was ready to be adopted in October; Trysh placed him into the cat carrier to take him to his new home, he totally freaked out, escaped into the eaves, escaped outside the house, and made it back to the colony two miles away two weeks later.

At one time Mystique was the only cat remaining in the colony; she was lonely so we decided that should Buckley wander into the trap (I TNR on a regular basis) we would move him back to the cattery.  Well, one day Buckley was really close to me so I scruffed him and placed him into the cat carrier I had handy; he didn't argue at all.

Since he's been back in the cattery, he's a changed cat: seeking affection, rolling onto his side, a really lovely, friendly cat. He's always been a relatively docile cat, but had been aloof and quite moody.  No more.

Is the change in behavior simply due to his realizing how good he had it inside, versus outside?  He and Mystique get along fairly well.  Petey is a bully, so he is kept in a separate room.

Thanks.

@Freya:  Buckley was neutered in late January 2011; he escaped in October 2011.

I guess Buckley realized how good he had it inside, including warmth, food and human companionship, and yes, when he was returned to the cattery inside, it was familiar (as was Mystique).  I think it helped too that when he made it back to the colony, I was familiar; it was a connection.

In any case, we are so glad Buckley gets a second chance at a Forever Home.