Last September, harbor seal pups in Massachusetts and New Hampshire started to die in droves. In today's New York Times, I write about what killed them: a new influenza strain that evolved from shorebirds to seals, possibly as recently as last summer. While controversy swirls around scientists experimentally nudging flu viruses across the evolutionary between birds and mammals, Nature has been doing some experiments of its own. Check it out. PS--The paper is in press at mBio. I'll post a direct link when there is one, which should be this morning. Update: Here's the paper.