This month’s cover image shows two male ruffs. The more colorful male on the left is an Independent male, the most common of the three types of ruff males. In this image, he is dominating a subordinate Satellite male as part of a mating display to attract females. For more context on the amazing mating behavior of the ruff, check out this video and some of the news coverage about the papers published in this issue (including this Nature News article. We also really like this one at The Guardian).
The genetic basis of the three male morphs found in this species was elucidated in large part in two studies published in this issue by Terry Burke and colleagues and Leif Andersson and colleagues. Both groups sequenced the genomes of the ruff and found a large inversion present in the two rarer male types, the Satellites and Faeders, that controls the appearance and mating behavior of the male. (See also the News and Views by Chris Jiggins and our editorial highlighting the studies).
The image shown on the cover was provided by photographer Torsten Green-Petersen. For more gorgeous bird pictures from this photographer (including more ruffs!), see his website at http://www.fagelnsblick.com/.