There is an interesting article: Young LC & VanderWerf EA (2013): Adaptive value of same-sex pairing in Laysan albatross. Proc. R. Soc. B 2014 281, 20132473, published 27 November 2013. The take home message: "Compared with the option of not breeding at all, female-female pairing may indeed be 'making the best of a bad job' in response to a shortage of males."
Here a link to the article:
and a link to a comment: