Jessica Harwood asked:
What are benefits of life-long mates if you're a bird?
We put this to Rebecca Kilner, Department of Zoology, University of Cambridge...
I donít think thereís a consensus in the scientific literature on this, but there are a couple of good ideas and the general theme is that if it takes two to rear babies effectively then you stick together with the one that you already know. So, that might be the case for example if nest sites are in short supply and it takes two of you to defend the site, then itís better to stick with the team-mate that youíve got than to change for the next season. Similarly, if youíre feeding your chicks on complex food thatís hard to forage for, itís better to stick with an experienced bird than to try your luck with a potentially naive individual.