In its air-popped way, it comes closer than the first Stuart Little film did to evoking the novel’s wistful vision of loyalty and friendship. Stuart, now comically integrated into the Little family, finds a comrade in Margalo, a troubled parakeet who drops into his miniature sedan. Michael J. Fox and Melanie Griffith voice these two with a vulnerable urgency, and the animation is so vibrant that you can practically reach out and touch the fur and feathers. Stuart Little 2 is lively without being hyperkinetic — it’s a bouncy mouse caper with a wee bit of soul.