Marsh Wren split based largely on our recent paper
The North American Checklist Committee just announced that it has accepted a proposal to split the Marsh Wren into two distinct species, in its annual Supplement to the Check-list of North American Birds, published today in Ornithology. This proposal recognizes the eastern and western lineages of Marsh Wren, which differ only slightly in plumage color, but strongly in vocal repertoire and song type, as two distinct species. The proposal to split these species was largely based on our recent paper, also published in Ornithology. In this paper, we used genomic sequencing to demonstrate that even in Saskatchewan, where these two vocally distinguishable lineages overlap extensively, hybrids are rare. This lack of hybridization, despite extensive opportunity (breeding side-by-side in the same marshes) suggests that strong reproductive isolating barriers exist. These barriers are preventing the Eastern and Western Marsh-Wren lineages from merging back into a single panmictic population, meaning that we can reasonably expect them to remain on divergent evolutionary paths.
In my opinion, this was a great decision. This updated species taxonomy now more accurately reflects the diversity of birds in North America, allowing us to understand, appreciate, and conserve our avian biodiversity with greater precision. I love being involved in research that uses museum specimens to update our understanding of biodiversity, and I think this is a great example of the type of real-world impact that systematics research can have! I am more excited than ever about what we will learn from future research on these awesome birds!
