You might think the avian imagery are the only thing the two have in common and that they couldn't be further apart other than that one superficial connection. One is a sex-and-violence-fueled drama for grown-ups, the other is an animated musical for kids. Rio has a happy conclusion; Game of Thrones may never end.
All the same, there's some darkness in Rio, most notably in the form of Nigel the cockatoo, who is arguably the main villain of the story. (There are both people and birds caught up in the plot machinations of the movie, ornithologists and pet owners and poachers and smugglers, so you could argue the greedy humans are the main villains, but go with me here.) Nigel is voiced by Jemaine Clement (of Flight of the Concords) and ... wow, he really breaks the mold.
Don't get me wrong, I admire the heck out of Jemaine Clement as both a writer and performer of some really sharp comedy. And he has a great voice, both speaking and singing, so he brings Nigel to life in a delightfully creepy way and gets to perform what is for my money the best song in the movie, "Pretty Bird".
And also don't get me wrong that I appreciate that there is a general tendency for children's entertainment, especially modern feature-length animated films, to be predictably formulaic. Heroes are reluctant but basically decent and learn important lessons about being true to themselves, while villains are power hungry or egregiously materialistic or both. On the one hand, if it ain't broke don't fix it, I get that. But on the other hand I applaud anyone who even tries to deviate from the proscribed boundaries, regardless of their success. So, Nigel got my attention because he's not trying to take over the world, to steal the crown of King of the Birds, or make a fortune by selling out the kindly old Mom and Pop Macaw business to developers or anything like that. His backstory, as relayed when he performs Pretty Bird, is this: he was once a famous TV star, and then he got old and got replaced. And because of the mental trauma associated with rising to the top and then losing it all because of the inexorable passage of time (and the entertainment industry's worship of youth above all else) Nigel became twisted and evil and sadistic, and now his only pleasure in life is making other birds suffer. He works with the bird poachers because it gives him the opportunity to torment other birds. He goes beyond being merely misanthropic (misaviopic?) and into terrifyingly Hannibal-Lecter-crazy; they literally depict him as a cannibal who enjoys eating chicken wings! Like I said, kudos for coming up with a motivation for the bad guy that's not totally rote, but like I also said, WOW.
There's something more than a little bit disturbing about hearing your six year old breaking out snippets of "Pretty Bird" at random moments, when they include lines like "I'm a feathery freak/With a beak/A bird murderer/You think you're badder than me?/I've never heard of ya". Yes, it's impressive that he memorized the lyrics after watching the movie only two or three times, and yes his flow is pretty good on the delivery, too, and yes, "murderer ... heard of ya" is a dope rhyme BUT STILL.
The climax of the movie takes place on board a cargo plane and Blu the heroic macaw outwits Nigel and manages to knock the cockatoo out of the hold. At which point Nigel gets sucked into the engine of the plane, in a moment which is more or less played as silly slapstick violence. But when I saw the movie the first time, given the context of Nigel's characterization, I thought it was not outside the realm of possibility that the implication was that Nigel had been brutally dismembered. Later there's an epilogue showing that Nigel survived, and merely was stripped of most of his feathers and made even uglier, which is pretty good comeuppance for the character driven over the brink by thwarted vanity, I guess.
There's a Rio 2 which none of us have seen yet, but I understand Nigel at least makes an appearance in the sequel. Nobody spoil it for me, but if they somehow make the bad bird even more bananas in the second installment, I may be ruined for kiddie flicks for life.