I’ve been wanting to write this post for a while, but I didn’t have a recent/decent photo to go with it. Yesterday, however, fellow Rogue Birder and friend, Jacob Roalef, messaged me with a fantastic photo of a Merlin that he had taken at Eastwood MetroPark. Given that I was about 15 minutes away, I thought, “here’s my chance!” Arriving at Eastwood, I found the bird within a minute or two perched alongside the lake. I was able to drive right up to him and fire off photos through my car window, resulting in a decent photo for my post!
So, here goes…
The Merlin is part of a group of birds called falcons. Throughout the history of taxonomy (the naming and classification of organisms), it was thought that falcons were closely related to other raptors, including hawks, eagles, kites, and vultures. I mean, they look and behave similarly, right? This entire group was classified in the avian order “Falconiformes”. However, as scientists dug further into the genetics of birds, an incredibly surprising relationship emerged. Falcons are genetically more similar to songbirds and parrots than they are to hawks and eagles!! And it turns out that hawks and eagles are genetically more similar to woodpeckers and kingfishers! Additional research examining more DNA (including complete genomes) and using more sophisticated analyses has only strengthened this finding.
So, check out the phylogenetic tree below (created using publicly available data at birdtree.org). Find the Merlin; I arbitrarily placed it at the top of the tree. If you place your finger on the line leading to the Merlin (this is called a tip) and trace the line (this is a branch) to the left, you will hit a point where the branch merges with a branch leadig to the American Kestrel. This point shows that, of the birds I included in this analysis, the Merlin is most closely related to the American Kestrel.
Continue tracing the branch to the left; it then merges with a branch leading to the Peregrine Falcon, Prairie Falcon, and Gyrfalcon. Thus, the Peregrine, Prairie, and Gyrfalcon are more closely related to each other than they are to the Merlin and Kestrel, but they are the “sister” group of the merlin/kestrel group.
Now here is where it gets really cool!!! Continue moving to the left along the branch, and you will find the next most closely related group includes the parrots and the perching birds (including songbirds). Only when you move further to the left do you find a point where this branch merges with the branch leading to hawks and eagles! And this branch also leads to woodpeckers, kingfishers, owls, and a number of other birds not included in this analysis. Note that owls are genetically more similar to woodpeckers and kingfishers than they are to hawks and eagles—another really cool result! Trace your finger along the branch starting at Owls to convince yourself of this!
The length of the branch from the tip to the point where two branches merge tells you how genetically similar are the birds. This tells us something about how long ago the birds shared a common ancestor. Shorter branches = less time; longer branches = more time. So, the falcons shared a fairly recent common ancestor, but the common ancestor of falcons, songbirds, and parrots existed a long time ago! And the common ancestor of falcons and hawks is even older!
Since the publication of these results, the taxonomy of birds has changed dramatically. Falcons have retained the name Falconiformes, but hawks, eagles, and kites have been placed in a new order, the Accipitriformes. Given how long ago vultures shared a common ancestor with hawks and eagles (check out the phylogenetic tree to see this), they have been placed in their own order, the Cathartiformes. If you have updated to the latest edition of Sibley’s field guide, you might have noticed that falcons are no longer placed near hawks, eagles, and vultures; you’ll find them just before the parrots but after the woodpeckers. If you are an eBird lister, you might have noticed the same placement of falcons on the checklist—they are nowhere close to hawks. If you read the entirety of this post, you now know why! And welcome to the world of phylogenetics—I love this field!
Merlin (Falco columbarius)
Eastwood MetroPark, Montgomery Co., Dayton, OH
26 January 2018