Northern Red-tailed Hawk -- Comments and Opinions

Some months ago, the subspecies abietciola for the Red-tailed Hawk, often called the Northern or Canadian Red-tailed Hawk, was removed from iNaturalist and all sightings identified as the subspecies has been replaced with simply “Red-tailed Hawk”. The main reason for this change was because the Clements Checklist doesn’t recognize it. The Clements/eBird Intergraded Checklist lists the subspecies as a form. I created a journal post in response to iNaturalist’s descision to remove the subspecies and how any taxonomic action at this point of time is premature. I would encourage you to read it before continuing on here.

I did say in the post however that rufous/dark morph abieticola has been hypothesized. Well, I happened to be scrolling through some top-rated photos of the subspecies on eBird and found this. An “abieticola” dark morph, identified by a raptor banding station and a knowledgeable, well-known birder. It’s not the only one either. A couple more examples. – Note: Raptor expert reported it.

And Brian Wheeler, the biggest activist per say in denying a northern race of Red-tailed stats in his book Bird of Prey of the West, he stats “Color Morphs: None in these 2 subspecies [borealis and kriderii]”

I’m still trying to work out how to identify dark morph calurus and abieticola but I do see comparing photos is that abieticola has a broader subterminal band that is nearly a terminal band, more maroon-rufous breast instead of tawny-rufous, and when viewed in flight from below, tails almost look harlani as in this individual.

Now it’s discussion time. What are your thoughts on this topic? Should abieticola be reinstated as a subspecies on iNat and we deviate from Clements? Or would you rather wait for more life history?


Even though I do think it can be somewhat distinct and from time to time report abieticola on eBird, I’d like more life history and more genetics work to be done before reinstating it as a subspecies. It’s still a somewhat controversial variety, to my knowledge on the subject.


Please note the flickr album referenced in the text is likely gone as I did not renew my pro subscription, and am unsure what they deleted. Technically they should have left 1000 pics per a free account but I cant even login so they may simply have nuked everything

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In terms of if it should be put back, a group of people paid to be world class bird experts have decided it should not be present for now. I think a really compelling case would need to be presented to differ from that, especially since it is not a case of new research that they may not have had time to review yet


Agreed, I don’t think iNat should just restate it without support from at least a few sources.

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I agree with you that I would like more life history being done. However, I don’t see why abieticola is always lumped with borealis. I agree with Avibase that if abieticola is not a subspecies, it’s a variation of calurus (because of dark morphs) not the other way around.

Isn’t the decision on the existence of a subspecies purely based on it consisting entirely of a genetically-distinct, “clade-like” population? And the existence of distinct forms/morphs (even when they are particular to a given subspecies) is incidental and not necessarily related.

Not an expert, so maybe this is off-base. My reading on this topic came from trying to piece together what the subspecies of Cervus canadensis were.

I also forgot to add the alternatives to deviating from Clements. Here’s what I and a couple others had in mind.

  1. Create an Observation Field for abieticola. Pros: It would put all sightings under one roof without it actually being a taxon. Cons: If I were to create it, I’d probably be the only person using it because I’ve noticed not many people use Observation Fields besides the field creator. To combat that issue, I think…

  2. Create a Project titled “Northern Red-tailed Hawks” or something among those lines. Pros: Same as Observation Field with the addition of letting several people admin the project and oversee the sightings. Cons: Keeping non-abieticola observations out of the project.

  3. Label all abieticola as borealis and if subspecies is reinstated, we’ll just have to sort through the sightings.

My laypersons understanding is that a subspecies is effectively “on it’s way to becoming a species, but just not quite there yet”. I see situations where two geographically isolated groups might start developing behavioural patterns that then socially preclude them from inter-breeding, but they technically could inter-breed, and probably would do, if not presented suitable “own sub-species” candidates. At some stage, an observer is going to note “I can see behavioural differences between these”, or “their calls are different”, and someone will decide that the difference is discernable and consistant enough to split to different ssp. Then someone else will come along and decide that it’s just normal variation, and then a study will be done, and then everyone debates it and eventually a concensus is reached, by which time the laypersons have long given up on it and gone back to just observing other cool stuff…

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Hi birdwhisperer,

Thanks for drawing attention to this conundrum. The existence of abieticola and identification criteria used to ID it have mostly been off of my radar, so I appreciate you bringing it to my attention. I’m not really clear on why iNaturalist is not following the Clements/eBird list of subspecies (essentially an updated version of Clements).

Thanks for providing a wealth of information in your write-up. It was very informative. Reading though your journal post, I noticed a few typos (Distrubition header; furtesi) , but more importantly, in your description of an abieticola type bird from Tennessee, you state the following, “Despite the similarities this individual shares with northern populations, there’s two solid features here that’s telling me it’s an abieticola.” If I am reading your intent correctly, it should read “telling me it is NOT an abieticola,” right?

While some of the described Red-tailed Hawk subspecies may prove to be invalid, they do make good reference points for discussing and characterizing the variation in the species. Both Dickerman and Parkes were career taxonomists, and the fact that their insights have been supported through fieldwork by the likes of Ligouri and Sullivan suggests that they should be given some weight.

Short of it being reinstated, I would advocate for you creating a Project of the sort that you curate.


Just to clarify, Clement’s (which is the taxonomy used in iNat) does not recognize albieticola as a subspecies in their 2019 checklist. The eBird taxonomy treats albieticola as a “form”, and not a full subspecies. Clement’s doesn’t include forms in their taxonomy, which is why that taxon is not an option in iNat.


Thanks for the clarification. That got me referencing the BNA account. Kriderii is listed as a subspecies on iNaturalist, though it is treated as a color morph of borealis (as is abieticola) in the BNA account (and presumably eBird). Shouldn’t kriderii and abieticola be treated similarly in iNaturalist?

Edited to acknowledge inconsistencies between Clements Checklist and BNA/eBird. It is weird to me that the Clements checklist considers kriderii a valid taxon while BNA considers it a color morph like abieticola. But I understand now why one is in iNat while the other is not.

Thanks for pointing it out, I’ll get it fixed. What I need is a professional editor because even when I read through like five times, I still never get all the mistakes.

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You’re welcome. That’s pretty universal in my experience. It is always much easier to spot other writer’s typos than to spot your own. :-)


I think the main reason those inconsistencies arise is the lack of any taxonomic authority to vet subspecies in North America - the AOS doesn’t do it, so it is left to individual authors to decide what to do. There’s a much higher degree of consistency at the species level, where I think Clement’s and the AOS only disagree on a handful of taxa.


A troubling thing about giving abieticola subspecies status is that the maps that I’ve seen show its breeding ranging stretching in an east-west band across much of Canada.That seems unusual as subspecies go. It almost suggests that evolution has favored darker coloration in northern Red-tails. In studying dark birds wintering in New York State, there is variation from birds that seem to be distinctly “abieticola” to birds that seem to be intergrades with eastern borealis. One thing that I’m not seeing here is multiple tail bands, which is said to be a characteristic. And, in fact, that does seem to occur in many birds to the west (pictures can be seen in Jerry Ligouri’s Birding article (Volume 67 (2014) - Number 3)). So that suggests that they intergrade with western calurus in the western part of their range, if not just a richer colored form of calurus. Although Jerry wrote the article referring to abieticola as a subspecies, he did not go with that designation in personal communication. In any event, they’re interesting looking birds, and I’ll be soon visiting a favored Red-tail wintering area in search of more examples.

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To continue the conversation I had this… heated discussion with some raptor experts after there was a dispute over a subspecies identification. Let’s keep in mind that Brian K. Wheeler is the leading activist for making abieticola a form of borealis Red-tail. And I’ll add @psweet to this conversation since he’s the one who recommended his book to me. I’m going to provide some dialogue to my discussion with some of these very knowledge raptor people. I apologize it’s lengthy but it explains how other experts in the field feel about Wheeler’s work.

Me: Hard to tell how long the primary extension is.

Kara Zambricki: Can you expand on primary extension in regards to Red-tailed Hawk subspecies? Thank you.

Me: *explains how Wheeler says borealis has much shorter primary extension than any other subspecies.

Shane Brown: That’s definitely incorrect on juveniles…Wheeler made an incorrect statement… Email him and ask about his banding data he’s using for these oddly specific measurements… I’m just confused by his 1 year old bits. Is he saying there’s a difference between juveniles and 1yo and adult? It’s the tail length that changes, not the primary length. There is no subadult, only juvenile and adult. It’s confusing and probably false like a lot of hastily published and inadequately researched statements.

Me: He calls pale eyed adult plumaged Red-tails 1st Years.

Mike Borlé: Really? I guess I need to read that book for the hell of it.

Shane Brown: Woooow. The eye color thing is straight up silly. I guess all the heavily marked birds that show up in Eastern Winters are Westerns? This is going to be a long decade dealing with this book.

Gail Kozun Bruckner: Ironically I think abieticola has more validity of being an accepted subspecies than Fuertes? (as mentioned in the Raptor ID app image 11 of 12 in borealis/Eastern)

Me: Actually no, he has like this 12 page thesis or whatever explaining that borealis has more variation then birders credit and “abieticola”-like individuals can be spotted throughout the breeding season in eastern US. He also claims that the reason there are more heavily marked hawks in Canada is because of calurus and Harlan intergrading…My thought process is, if abieticola is not a subspecies then alascensis should be lumped with calurus and calurus should be lumped with borealis (because it’s similarities with abieticola) and fuertesi is lumped with borealis.

Shane Brown: Alascensis was based on a handful of specimens. They’re just colorful Westerns from BC. I don’t even know how the name came about. Fuertes is mistaken as a subspecies. They’re just pale Easterns and some of the lightest Westerns that happen to be in the proposed range, but we know their phenotype is all over outside the proposed range… Harlan’s influence doesn’t come close to explaining the Northerns that show up from Ontario and Quebec into the Midwest and East Coast. The birds that show up in Winter only are not just like the breeders they join or replace. Anyone paying any attention sees that. We have Macaulay Library now. Just look at it! It’s so easy… I’m a birder and I’ll give variance within borealis a ton of credit. Search this page over the years and you’ll see that from me and many others. Maybe Wheeler should, too. I still want to hear about his banding data and all his other bases for his claims. Where does some of this come from? His sample sizes seem tiny across the board.

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