The 58th Supplement to the AOU checklist was released today...

Happy Canada Day! The annual Supplement to the AOU Checklist was releasted today. I am only going to speak about changes that will affect us in North America.

We lost Thayer's Gulls from the list and it is now lumped with Iceland Gull (Larus glaucoides). Jon Dunn and Van Remsen gave strong arguments as to why the Thayer's Gull should be nixed from the list. They proved that the research used to determine its full species status was flawed. They argued that the research didn't prove that it was distinct from an Iceland Gull. Therefore all those Thayer's on your list will now be an Iceland Gull.

Everyone said that Yellow-rumped Warblers would be split into Myrtle and Audubon's well that didn't happen either. The split was rejected. So some may be disappointed now, as many were separating it on eBird for this very fact and they will not gain another species.

Other proposed splits that were rejected were those for the Willet, Brown Creeper, Bell's Vireo, Nashville Warbler and Hoary and Common Redpolls. The Redpoll split was a contentious one and there were many who wanted them lumped. I personally am thrilled with the decision. I never wanted them lumped especially seeing how different these birds are in the arctic. I am not a person that enjoys the splitting of species unless absolutely necessary and proven by scientific fact. Therefore, now in North America there will be 3 distinct species of Redpolls: The Hoary Redpoll, The Common Redpoll and the vagrant Lesser Redpoll.

I tend to not ever take much heed into the talk of splits until the supplement comes out.Things rarely turn out the way birders think they will.

We gained one new North American species though! This bird is called the Cassia Crossbill and it lives and breeds in the South Hills and Albion Mtns of the state of Idaho. It is larger than Red Crossbills and has a distinct song and call. You can listen to them HERE

Another interesting thing happened, the Northern Shrike is now deemed to be different from the Great grey Shrike. The Northern Shrike reverted back to its old subspecies name Lanius excubitor borealis.

The Northern Harrier is now also split from it's critically endangered (only 4 breeding pairs left in England) European cousins, the Hen Harrier (Circus cyaneus). To read more about the Hen Harrier's terrible plight and how the world may lose this species forever (mostly due to illegal killings by grouse hunters) click HERE.

Finally, the Yellow-breasted Chat is out of the Warbler category. I am very happy about this, as it was the weirdest warbler I ever saw, never behaved or looked like one to me. The Yellow-breasted Chat will be in its own family now called: Icteriidae. It will come now before Orioles and Blackbirds in field guides.

All North American sparrows will now be in their own family called Passerellidae

The complete text of the supplement will be out soon and more will be discussed in detail in there; along with more answers to some more proposed changes. Like, will they change the name of the Ring-necked Duck? You can see the list of what the current proposals were HERE. We still have a lot yet to find out.

I will update when the full text of the supplement is released.

Source: Rick Wright


  1. Not surprised with the Thayer's and chat decision. A liitle suprised that the redpolls weren't lumped, thought the science was strong on that. Am relieved we don't have a number of new crossbill species to figure out! I get the feeling that the AOS is becoming more reluctant to split species. With the present thinking, for example, I don't think western flycatcher would ever have been split.

    1. thanks q, appreciate your thoughts. Guess the science wasn't as strong as we thought on the redpolls. i think it's neat we have a new crossbill. I listened to it and it sure sounds differents. i am glad the aos doesn't want to split species. like you are relieved we dont have multiple crossbill species im relieved we don't have multiple white-breasted nuthatches lol!


Post a Comment

Popular Posts

Dowitcher Identification

Hawk Identification Tips from every angle (Sharpie vs Cooper and Red-tailed Subspecies)


*Updated - The most famous Red-tailed Hawk is eating fish on the ground just like a Bald Eagle!

*UPDATED* The First Ever Black Birders Week May 31-June 5th