Director Carlos Saldanha ("The Ice Age") is a Brazilian himself, and infuses the movie with the tropical colors and salsa rhythms of his homeland, and you wait for the emotional payoff that might come from what is surely a labor of love.
That payoff, however, is disappointingly small, and "Rio's" insistent tempo and zesty 3-D color starts to feel like cover for a routine story and mostly forgettable characters.
"Rio" pushes two non-starting love stories - Eisenberg's nerdy, fearful city bird gets lessons in flying and courage from his prospective mate, while his human owner (Leslie Mann) falls for a South American ornithologist.
A band of bird smugglers goes after the rare macaws, which flee to the jungle, where they're helped by a jolly toucan (George Lopez) and eventually a drooling bulldog (Tracy Morgan).
The plot leads to standard chase mechanics, populated by thinly sketched characters who are saddled with bland dialogue and sometimes are moved to sing unmemorable songs.
One exception is Jemaine Clement ("Flight of the Conchords") as the voice of the smugglers' bird henchman, pursuing the macaws through the rain forest and eventually into Rio for Carnival.
Clement's deep, sonorous, kiwi accent turns out to be particularly well-suited to animation and to villainy, though the more strongly he registers, the more pronounced is the gap between his character and the figures around him.
Clement aside, the strongest selling point to "Rio" is its 3-D presentation - the colors are unusually strong even through the palette-dampening glasses, and the many action scenes proceed without the strobey distractions of substandard technology.
Produced by Bruce Anderson, John C. Donkin, directed by Carlos Saldanha, written by Don Rhymer, Joshua Sternin, Jeffrey Bentimilia, Sam Harper, music by John Powell, distributed by 20th Century Fox.