The American Ornithologists Union (AOU) is, among other things, the arbiter of avian taxonomy in Middle and North America. They are the organization that rules on whether a species should be split in two, or if two species should be lumped together. They are the organization that rules that Loons are no longer the most basal group of North American birds, but that they group that contains ducks, geese and swans holds that honor. The AOU releases all these decisions in the form of annual Supplements to the official AOU Checklist (which is a complete list of all bird species and subspecies listed in taxonomic order).
A lot of science has to be done before the AOU makes any of these ruling, and these ruling are subject to change as more science is done, but at any given time, the current AOU Checklist represents the best available knowledge on how many species of birds there are and on how they are all related to one another.
Well, the AOU just released their most recent Checklist Supplement and it has, among the many updates and changes, an interesting change for California. Since that is where I live, I am particularly interested in this one. It concerns a common member of the corvid family that anyone who has spent any time outside has seen. The Western Scrub-Jay (Aphelocoma californica).
This species has actually already had an interesting history in the taxonomy world. Before 1995, there was one species recognized as a Scrub Jay (Aphelocoma coerulescen). This species was found across the western USA and also in Florida. In 1995, the AOU split the Scrub Jay into three distinct species. They were the Florida Scrub-Jay, which retained the original scientific name (Aphelocoma coerulescens), recognizing the Florida population as genetically distinct; the Island Scrub-Jay (Aphelocoma insularis) recognizing the population found on the Channel Islands off the coast of southern California as genetically distinct; and the Western Scrub-Jay (Aphelocoma californica) which included all the remaining populations in the western continental USA.
California Scrub-Jay (Photo credit: Frank Lang)
Now, in the most recent AOU Checklist Supplement, the Western Scrub-Jay has been split again. We now have the California Scrub-Jay (Aphelocoma californica) recognizing that the population along the Pacific Coast is actually genetically distinct from the Woodhouse’s Scrub-Jay (Aphelocoma woodhouseii) found in the inter-mountain west.
Woodhouse’s Srcub-Jay (Photo credit: Robert Mortensen)
In addition to the genetic distinctions, these two new Jay species also have behavioral and morphological differences. The California Scrub-Jay is darker in color, generally lives in Oak woodlands, and eats a range of seeds including a lot of acorns and so has a heavier bill. In contrast, Woodhouse’s Scrub-Jay is lighter in color, generally lives in the Great Basin pinon-juniper scrublands, and correspondingly eat a great deal of pinon pine nuts and juniper berries and so have a slimmer bill.
So, update your life lists, start getting used to using the new four-letter codes of CSJA (now standing for California Scrub-Jay) and WSJA (Now standing for Woodhouse’s Scub-Jay, and not Western Scrub-Jay that it used to identify), and enjoy picking apart the finer levels of identification between these two newly recognized species!
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