NPR take a look at the "divorce rate" among birds:

Flamingos, it turns out, are embarrassing. They break up 99 percent of the time. The divorce rate for piping plovers is 67 percent. Ducks do better than humans. Human marriages (American ones) fail at a rate of roughly 40 percent (which is about equal to Nazca boobies). Mallard marriages are 91 percent successful. The big shock was swans. Everybody, ornithologists included, figured swans would be at the top of the Most Faithful list. But they're not. They have a 5 percent divorce rate. So who's the champ? Do I need to say? Albatrosses are 100 percent faithful. That's not to say that albatross dads don't occasionally have a dalliance with ladies who aren't their mates. That happens. But the original pair stays intact—which is surprising when you consider that albatross couples can last for decades.

Unless male albatrosses are scrupulous about dallying—that's NPR for "fucking"—only with single lady albatrosses (albatri?), the female of the species is getting it elsewhere too. But the albatross may have a more workable definition of "faithful" than the one humans have been saddled with: a lasting partner bond with the occasional dalliance, aka social monogamy, not sexual monogamy. Another thing albatrosses seem to do right: they spend a lot of time apart—sometimes months alone. Research shows that human couples who do the same are happier and have stronger relationships.

UPDATE: Yes, yes—human beings are not birds, as folks are pointing out in the comments. That would be a more devastating point if birds long believed to be monogamous—because they were socially monogamous—had not held up for centuries as a moral example to human beings. Then along comes genetic testing and we discover that—lordy!—none of those birds we'd been hearing about were sexually monogamous. So we had a lot to learn from birds when we believed they were monogamous. Now that we know they're not... nothing to see here, folks, move along.

And it wasn't too long ago that social conservatives were cheering March of the Penguins, a documentary about the mating habits of penguins that "[affirmed] traditional norms like monogamy, sacrifice and child rearing," according to social cons:

Rich Lowry, the editor of National Review, told the young conservatives' gathering last month: "You have to check out 'March of the Penguins.' It is an amazing movie. And I have to say, penguins are the really ideal example of monogamy. These things—the dedication of these birds is just amazing."

Reality, however, has a liberal non-monogamous bias:

Emperor Penguins are serially monogamous. They have only one mate each year, and stay faithful to that mate. However, fidelity between years is only about 15%. The narrow window of opportunity available for mating appears to be an influence, as there is a priority to mate and breed which often precludes waiting for the appearance of the previous year's partner.

To recap: "Penguins are monogamous? People should act more like penguins! Penguins are a shining example to us all! Wait—penguins aren't monogamous? People shouldn't act like penguins! Penguins are animals and their example is entirely irrelevant!"