Is Angelina Jolie or the Saltmarsh sparrow a bigger slut?They're both small-boned, don't eat much -- and tend to have a tough time with monogamy.

This week we can't get enough of the idea that Angelina Jolie and Brad Pitt might be on the rocks after Angie's alleged affair on the set of her new movie, "Salt." Meanwhile, science has named the Saltmarsh Sparrow the world's most promiscuous bird.

Coincidence? We think not.

Recently researchers found that 95 percent of the Saltmarsh females mated with more than one male during each nesting period. Swap in "filming of each Hollywood flick," and we may have a match.

Angie first sunk her claws into Brad while filming "Mr. and Mrs. Smith," when he was still nesting with Jennifer Aniston. Now her language lessons with an on-set tutor are rumored to have included vodka, sex toys and rubber sheets, says one hotel maid.

While the Saltmarsh Sparrow doesn't do one-night stands, in the course of its four-week mating period it does choose a variety of birdie-daddies to sire a batch of babies. In fact, what Professor Chris Elphick learned from studying the birds' mating habits up close was: Mom was getting more on the side than even Tiger Woods -- only 5 percent of sibling sparrows all shared the same father.

Now back to Ang: Of course, there's no contesting the fact that, with the exception of Shiloh and twins Knox and Vivienne, each of Angie's mini–model citizens has a different dad. Besides that, there have been rumors since the days of Billy Bob that she's actually bisexual, and she's gone public with the fact that she's not big on monogamy.

Fine by us -- to each her own. The point is that the similarities between Brangie and the birdies may hold some dating (and mating) wisdom. After all, even science knows you shouldn't expect a bird of a certain feather to molt and wake up monogamous.

Only 3-5 percent of species in the animal kingdom are loyal for life, and not a one rethinks its behavior patterns halfway through.

What do you think: Did Angie simply fall prey to temptation -- or is she a born cheater who won't change?