Funk, E.R., Mason, N.A., Pálsson, S. et al. A supergene underlies linked variation in color and morphology in a Holarctic songbird. Nat Commun12, 6833 (2021). https://doi.org/10.1038/s41467-021-27173-z
For iNat users who haven’t had the pleasure…Redpolls are tiny, antic northern finches that wander south to backyard feeders each winter. In my neck of the woods (Northwestern Ontario, Canada), Common and Hoary Redpolls are regular winter visitors I always look forward to seeing when the snow arrives. Love them.
The challenge is: the differences between Hoary and Common are often so subtle that it can be impossible to get agreement on an identification. A truly astonishing amount of time and energy has been spent debating Common vs. Hoary on who-knows-how-many Redpoll records.
I am very much in favor of lumping these Redpolls as soon as possible. My sincerest wish is that this will be the last Christmas Bird Count season I have to split Common/Hoary hairs.
What would we call the lumped Redpolls? As the birds have a holarctic distribution, Arctic Redpoll would make perfect sense. I would look forward to hearing other suggestions.
This a frequent problem with moths, although usually it is different species that cannot be visually separated.
While I’m not a bird expert, I’m old enough to remember Red Shafted and Yellow Shafted Flickers which are now Northern Flickers. Arctic Redpoll sounds good. I have not had the dubious pleasure of having to identify them even though where you and I live are relatively close physically.
I think you had it right in your title - I have to vote for “Lumped Redpoll”. It would certainly memorialize the angst and effort it took to get to this point!
As much as I agree that the redpolls should probably be lumped, I find the ID challenge fun and I don’t want to lose Hoary Redpoll off my life list.
Disclaimer: I live far enough south that any redpoll I don’t get a good enough look at can be safely assumed to be Common, so I don’t have to deal with the ID challenge too often.
Looking at the distribution maps, there is a suspicious absence of the hoary redpoll* from the UK. There are hoary redpolls in Scandinavia, France, and other parts of Nearctic Europe, but zero in the UK, despite our local hordes of dedicated birdwatchers. I wonder if the UK community has already gone ahead with your suggestion and is lumping all sightings under the Common Redpoll name?
*Ironically shown as the Arctic redpoll for UK users
While I generally agree with the assessment that they’re probably one species, I wish ornithologists would actually apply species delimitation methods to these questions even though those methods are often flawed. The Northwestern Crow lump, while probably valid, was never actually a hypothesis really tested- AOS just saw a large hybrid zone and lumped them. Same with the Iceland Gull lump. This particular case, however, is a little better explored and I generally agree with the assessment that they’re once species. The authors actually provide actual evidence here.
However, the rationale I often see online for wanting the lump/split is a little disappointing and myopic. Species are under no obligation to be field-identifiable. Cryptic species are real and they’re quite common. The over-application of the biological species concept is a plague; speciation is a complex process of which gene flow and morphological stasis are important components.
But maybe I’m just a grump, a poopypants, and a killjoy.
The name “Arctic Redpoll” is already in use for A. hornemanni outside of North America. If all three currently recognized species of redpoll (Common, Lesser, and Arctic/Hoary) are lumped, and I do believe they should be, the common name will likely be simplified to Redpoll.
Another issue with Australian Magpie would be that there are multiple species of Corvids that use that name, in Europe, Asia, and North America. At least with respect to North American birds, the rules that govern common names aren’t well-established at all. Oddly enough (by the standards of some more recent proposals, in any case) the 2016 proposal to lump the Redpolls didn’t provide a recommendation for a common name.
We can have one species and call it “The Redpoll”…that’ll be memorable.
For the record I find lumping of these species curious. The current species and their subspecies clearly have geographic trends that support them as distinct taxa, regardless of how different their genetics is. Difficulty of field ID to species should not be any support for their lumping, ever. Golden-winged warbler also comes to mind. I think it’s time people stop using genetics as the sole deciding factor.
I think it’s the one-two of clinal variation in phenotype coupled with the clinal variation in the supergene Funk et al (2021) found that does it, not just genetic work. Redpolls can be pretty difficult to distinguish in the field (at least Hoary/Common can, I don’t have experience with the other taxon) because of that, it’s a symptom. To me, this seems like a case of local adaptation rather than speciation (or maybe like, genic speciation).
Toews et al (2016) found six areas of the genome that were differentiation and tightly tied to plumage variation- to me, this suggests a mode switch from genic to genomic speciation. I think that’s the difference. At least, that’s the difference for me.
wrote “A latitudinal gradient in ecotype distribution suggests supergene driven variation in color and bill morphology are likely under environmental selection, maintaining supergene haplotypes as a balanced polymorphism. Our results provide a mechanism for the maintenance of ecotype variation in redpolls despite a genome largely homogenized by gene flow.”
What that says about taxonomic relationships depends on how you define the word species. The problem is that all the definitions of species begin from the assumption that the perception of species is rooted in fact not illusion. After over a century and a half of attempting to find a species concept that covers every instance of a living thing perceived to be species there is still no unitary definition.
The evidence is strong that the notion of species is, in fact, a generalization based in large part on religious/cultural traditions like the Biblical story of the flood and Noah’s ark. It is not, or at least not yet, an empirically derived category rooted in the scientific method. Words have power, but part of their power is the power to obscure. Trying to shoe-horn a 5,000 year old notion of how nature works into a scientific definition is a mug’s game. The insistence that nature must conform to all the assumptions embedded in an English-language word rooted in cultural artifacts from a time when people believed that the sun went around a flat Earth is hubris. Nucleic acids do weird things and a few of them don’t fit with the cultural baggage of our language.
Will we ever have a universal definition for species? There isn’t a simple answer, at least not in English. The beautiful, rich, poetic Russian language has one - авось. It sort of means maybe/maybe not/I hope so all at once. Personally, I doubt it.
That does seem to be the majority perspective but I really don’t find the arguments in either direction persuasive. You can make an argument in favour of either position depending on where you place the boundaries on defining species.
The complexity of the evolutionary relationships among types is much more interesting than “is it a species or subspecies?” It can be very hard to tell the redpolls apart but there is a genetic basis to phenotypic differences that do appear to be stable. Are they species? Sure. Maybe. I don’t know. I don’t really care. That these birds are difficult to pigeon-hole makes them more interesting. It would be a shame if iNat didn’t have some way to track observations in a manner that reflected that interestingness but the precise labelling convention is sort of beside the point.
Yeah, that’s what I supposed, people would be angry in loosing taxon completely, sp or ssp, difference isn’t big other than a check in a life list, but they’re separated that way and stay (more) valuable.
So then it’s a bit more about being clear about what properties we want a species to have rather than finding a one-size-fits-all definition that is always the case, no? Labels aren’t always empirically-derived but that doesn’t stop some from being useful in certain contexts (and not in others).
It’s not that species as a concept is fallacy so much as we need to put less stock in the label (outside science, including and especially from a legal and legislative perspective) and be more explicit that speciation as a process is complicated and so are things like population dynamics and standing variation. It’s not that “species” is illusory, it’s that we’re generally not clear and precise about what properties we want that particular box to have and what to do when reality doesn’t line up with that.
For what it’s worth, I’m a big fan of the evolutionary species concept resurrected by Wiley in '78. It’s unhelpful in diagnosing species, but Frost and Kluge (1994) point out that species concepts aren’t obligated to be useful to species delimitation. We’re after evolutionary distinct lineages with their own history and fate. Whatever that means.
