Many snakes stay in "feed mode" for a while even after eating...and while I doubt that your snake finds the kitten's scent to be attractive (in an edible sort of
way), it's quite possible that your snake is paying attention to the motion AND the kitten's warmth...remember that BPs have heat-sensing pits to find food.
And maybe he's curious about the scent too, who knows? If I was stuck in a room, I'd be looking out the window too...wouldn't you?