Rest in Peace in 2024, the Hoary Redpoll
By Ryan Mandelbaum
It seems like only yesterday that we were out in the frigid depths of winter, freezing our fingertips as we scanned hundreds of common redpolls for an ever-so-slightly different hoary redpoll to add to our lists. You can still do that activity, of course—but now, it’s for the sheer love of redpolls and subspecific identification and no added benefit to your life list.
It’s official: hoary redpoll is no more. And our European readers, too, have lost a redpoll from their life list (they’ve actually lost two with the lump of Lesser Redpoll as well), as the previous three redpoll species have now been lumped into a single species, redpoll.
While redpolls were included in Linnaeus’ earliest taxonomic work, biologist Philipp Ludwig Statius Müller first separated out the “mealy” redpoll, in 1776 on account of its smaller stature and darker streaking. Meanwhile, Carl Peter Holbøll first described the hoary redpoll in 1843 in his book on the fauna of Greenland. Since then, we’ve counted—and struggled to identify—these different redpoll species based on their plumage characteristics. Some have even recognized up to six redpoll species.
However, we’ve long struggled with whether these differences were enough for us to consider the redpolls different species, and in the past decade, calls to lump the three have been much louder. Genetically, there’s very little differentiation between the groups, as Funk et al. (2021) noted differences in plumages that are controlled by a chromosomally inverted “supergene” in charge of features like frosty plumage color in the Hoary Redpoll. And for now, bird list maintainers agree that all redpolls make up just a single species, redpoll.
 Redpolls on cattails |
But you never know if this is the end of the redpoll’s story—we’ll see. For one thing, there are plenty of species pairs or groups with extremely similar genetics, spare just a single place where their genes differ, like the hooded crow and carrion crow or blue-winged warbler and golden-winged warbler, for example. And while the studies into redpoll DNA did include information from the hornemanni and rostrata subspecies from northeastern Canada and Greenland this study — we still don’t have an assortative mating study on the breeding grounds. Maybe there are reproductive barriers in place more than we think…..we know those reproductive barriers aren’t great for the Blue-winged and Golden-winged warblers. Birders who’ve seen these birds will tell you that they are quite distinct, especially in their larger size.
Therefore, the authors of the redpoll Birds of the World account call out that there’s need for further study to understand the actual lines to draw if we hope to understand the different taxa of these birds. If they represent different species, they would assortatively mate, or only mate (>95%) with other members of their designated group. You’d also expect their songs to differ. All of these are areas of potential study.
So, goodbye for now, lesser and hoary redpoll. But I’ll still be looking for tiny-beaked, pale-rumped individuals whenever I come across a redpoll flock, similar to how I look for green morph pine siskins in every siskin flock. And maybe some day, further research will shake up our understanding of these charismatic songbirds once again.
Cover Photo Jay McGowan
The Finch Research Network (FiRN) is a nonprofit, and was granted 501c3 status in 2020. We are a co-lead on the International Evening Grosbeak Road to Recovery Project, and have funded almost $20,000+ to go towards research, conservation and education for finch projects in the last couple years. FiRN is committed to researching and protecting these birds like the Evening Grosbeak, Purple Finch, Crossbills, Rosy-finches, and Hawaii’s finches the honeycreepers.
If you have been enjoying all the finch forecasts, blogs and identifying of Evening Grosbeak and Red Crossbill call types (20,000+ recordings listened to and identified), redpoll subspecies and green morph Pine Siskins FiRN has helped with over the years, please think about supporting our efforts and making a small donation at the donate link below. The Evening Grosbeak Project is in need of continued funding to help keep it going.
Donate – FINCH RESEARCH NETWORK (finchnetwork.org)
Book Link
For help with Finch ID and much much more, here is a link to the exciting and newly released Stokes Guide to Finches of the United States and Canada: https://www.amazon.com/Stokes-Finches-United-States-Canada/dp/0316419931
Shirt Link
For a commemorative Winter Finch Forecast shirt that makes for a great holiday present, see here: https://finchnetwork.org/shop
Please think about joining Finch Research Network iNaturalist Projects:
Winter Finch Food Assessment Project/Become a Finch Forecaster: https://finchnetwork.org/the-finch-food-assessment-become-a-finch-forecaster
Red Crossbill North American Foraging Project: https://finchnetwork.org/crossbill-foraging-project
Evening Grosbeak North American Foraging Project: https://finchnetwork.org/evening-grosbeak-foraging-project