Bees do it. Humans do it. Even Starling females to it. Those naughty birds. They cheat on their mates just to protect their young. Seems the mother birds will play around if a male seems likely to help out at home.
There is evidence that the Starling female will mate with subordinate males when they need help raising their young. In the Starling family it's the females who leave the nest to branch out on their own.
They sometimes need more help to get things done so they get those homebody males to work with a little sex on the side. Males rarely leave their family nests.
Not to say Starling ladies are into inbreeding. If the linage is getting to close for comfort they will also go find some new blood. They will even do the occasional one night stand if it helps add to the gene pool.
"This is the first study to show that individuals from the same population mate with extra-pair males and gain both direct (like additional helpers) and indirect benefits (like better genes for the offspring), but that they do so in different contexts," said Dustin Rubenstein, a former Cornell graduate student in neurobiology and behavior and now a research associate at the Cornell Laboratory of Ornithology and a Miller Research Fellow at the University of California-Berkeley.
Starlings are not the norm of the bird world. Generally if a female strays then she's left to do all the work on her own just like in the human world. Not to say that every Starling cheats on her man. Most don't but those who do aren't punished by the other birds in their family.
"In most avian cooperative breeders, 40 to 60 percent of offspring are a result of extra-pair matings, but in superb starlings, only about 14 percent of the offspring are fathered by other males," said Rubenstein.
It seems that not feeling the guilt may make for stronger commitment.
