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WHY IT'S OK FOR BIRDS TO BE GAY
Nearly one-fifth of all long-term greylag gee upl are gay, posed of two mal. They're not alone: More than 130 bird speci are known to engage homosexual behavr at least ocsnally, a fact that has puzzled all, evolutnary terms same-sex matg seems to rce the birds' chanc of reproductive succs. In some speci the same-sex pairs even raise young (nceived wh outsi partners, obvly) and stay together for several 2007, a team led by Geoff MacFarlane, a blogist at the Universy of Newstle Atralia, reported that male homosexual behavr was more mon polygyno bird speci, where mal mate wh numero femal, and that female homosexual behavr was more mon monogamo speci.
Srg sexTo fd out whether the theory might extend to homosexual behavr, MacFarlane and his team exhstively bed the lerature for acunts of same-sex urtship, mountg, or pair bondg.
GAY GEE
They foced on the 93 bird speci whose homosexual teractns scientists had seen the wild.
For each speci, the team lculated the equency of homosexual behavr as well as both sex' ntributns to parentg. Overall, homosexual behavr amounted to ls than 5 percent of all sexual activy the 93 speci, though some s was much higher. And sure enough, there was a strong rrelatn between a speci' matg system and s homosexual behavr.
The balance shifted to femal socially monogamo speci, where the sex spl the work more far, female homosexualy hasn't turned up the handful of birds where each female mat wh many mal, but MacFarlane's team predicts may. "Homosexual behavr is more likely to be mataed and not be selected agast than if you are a sex that r a lot for offsprg and only has one or few reproductive partners, " he wh plenty of reproductive prospects, a ltle homosexual behavr won't have much effect on long-term reproductive succs, MacFarlane said. "That's que different to what the tradnal argument is the lerature, where homosexual behavr is seen as a st.