Global warming stresses bird marriages

Scientific American has been a surprisingly sexy magazine as of late, with Jesse Bering's classic ode to semen, and now a cheeky look at global warming and bird biology. The headline:

Climate Change increases mate-swapping in birds

A study by Carlos Botero et al in PLoS ONE reveals that, the mag says: .

Birds typically bond to one partner throughout a breeding season and sometimes nest with the same mate year after year. Before the 1990s, this phenomenon led scientists to believe that more than 90 percent of all species were monogamous, but thanks to improved genetic testing, we now know most birds actually stray from their partners.

Despite birds' long history of infidelity, extreme temperature fluctuations appear to be intensifying the effect. If global climates continue to grow more erratic, the affected areas could see a steady increase of promiscuity among birds, Botero says.

Translating this idea from the study:

We show that after controlling for potentially influential life history and demographic variables, there are significant positive associations between the variability and predictability of annual climatic cycles and the prevalence of infidelity and divorce within populations of a taxonomically diverse array of socially monogamous birds.

Real news may be the evolutionary logic revealed. To increase genetic variability, to better allow survival of young in a wider array of conditions, temperature stress drives infidelity in birds. 

h/t: Jess Zimmerman/Grist