Sneak Peek: In 'Rio 2,' love is not just for the birds

• Blu %28Jesse Eisenberg%29 and Jewel %28Anne Hathaway%29 have sporting a family of three grown macaw children in the sequel %27Rio 2%27
• Kristen Chenoweth joins the cast of %27Rio 2%27 as Gabi the poisonous frog
• The film is due in theaters April 11%2C 2014

The most unlikely rare-bird couple alive now has company.

In 2011's lushly animated hit Rio, domesticated macaw Blu (Jesse Eisenberg) and his wild same-species blind date Jewel (Anne Hathaway) hit it off and sent box-office sparks flying. Now, the birds — and the bees — have really kicked in for the 3-D sequel Rio 2 (due out April 11).

The couple has three grown macaw children and has to deal with the discovery of unexpected relatives — a problem that plagues the avian world as much as it does humans. To boot, there are new villains aiming to do some fowl damage on the clan.

"Isn't there usually someone to spoil any party?" asks Kristin Chenoweth, who voices Gabi the poisonous frog. "We all have those people in our lives that just get in the way."

It's a shame since Rio 2 starts off as a happy multi-species couples-fest. Blu has joined Jewel at a beautiful rare-bird reserve in Rio de Janeiro, and the couple has started a family consisting of eldest bird Carla ( voiced by X Factor standout Rachel Crow), brainy Bia (Hunger Games star Amandla Stenberg) and young boy Tiago (Looper's Pierce Gagnon).

Little relationship annoyances, such as Blu's continued un-macaw-like insistence on making pancakes for the kids, are no big deal. Blu's former human owner Linda (Leslie Mann) has also moved from her cozy home in Minnesota to the reserve to be with the hunky wildlife preservationist Tulio (Rodrigo Santoro).

But the idyllic life gets disrupted when Jewel discovers that her long-lost father and his clan have been discovered hiding in the Amazon rain forest, where their habitat is under threat.

"So there's a big adventure to the Amazon," says Brazilian director and Carlos Saldanha. "It's very much a journey for Blu and Jewel's family. Feathers do get ruffled."

Part of the issue is that Jewel's relatives, led by radical patriarch Eduardo (voiced by Andy Garcia), don't trust humans — no matter how well-meaning. And Eduardo doesn't accept the domesticated Blu, even if the former house bird has learned to fly.

There's also Jewel's suave ex-boyfriend Roberto (Bruno Mars), who stirs up Blu's jealousy.

"Most of the sparks between the former couple are imagined through Blu's eyes," says Saldanha. "It's a little paranoia."

Threats are very real, however, from the deadly Nigel, the sadistic sulphur-crested cockatoo (Jemaine Clement). Defeated in the original film, Nigel is bent on revenge against the macaw family. "He's better and badder than ever," says Saldanha. "He's a delicious villain."

Nigel enlists the help of a non-speaking anteater called Charlie and Gabi the frog, who is besotted with the tuft-heavy cockatoo. Chenoweth insists her poisonous character is not bad, just a little "misunderstood" and emotionally vulnerable.

"Have you ever been in love before? Have you ever done something in the name of love you maybe wished you hadn't? That's my little Gabi," she says.

In the tradition of Rio's Oscar-nominated song, Real in Rio, the Nigel-Gabi pairing allows Chenoweth and Clement to sing together. The Broadway veteran calls the result "magic."

"I will say it and stand by it, this is the best song by a poisonous frog ever," says Chenoweth. "People love a song about heartbreak. Has it ever been told from the viewpoint of a female poisonous frog? I don't think so."