How many redpoll species exist?

This video from England says about itself:

Arctic Redpoll – Aldeburgh, Suffolk, 13 December 2012

16 December 2012

As a species, Arctic Redpoll is no longer considered an official rarity in Britain. However, that’s only because the subspecies exilipes (Coues’s Arctic Redpoll) has occurred in increasing numbers in recent years – including in some notable influxes.

The nominate form hornemanni (Hornemann’s Arctic Redpoll), from Greenland and adjacent Canada, remains a true rarity and is still treated as such (just 90 records by the end of 2011). Mainland occurrences of Hornemann’s in Britain have been non-existent, or almost so, until 2012; after an earlier belatedly identified bird in Norfolk in the autumn, this individual in Suffolk found its way onto many lists, including mine. Filmed in HD using a Canon EOS 7D with EF 500 mm F4 lens and 1.4x extender. Thanks to Ed for his help with the editing of this clip.

This video from England says about itself:

Coues’s Arctic Redpoll, Hazlewood Common, Suffolk, November 2017. It comes into focus after a few seconds!

Another video used to say about itself:

Coues’ Arctic Redpoll (Carduelis hornemanni exilipes) HD

20 February 2012

The Arctic Redpoll (Carduelis hornemanni), known in North America as the Hoary Redpoll, is a bird species in the finch family Fringillidae. It breeds in tundra birch forest. It has two subspecies, C. h. hornemanni (Greenland or Hornemann’s Arctic Redpoll) of Greenland and neighbouring parts of Canada, and C. h. exilipes (Coues’s Arctic Redpoll), which breeds in the tundra of northern North America and Eurasia. Many birds remain in the far north; some birds migrate short distances south in winter, sometimes travelling with Common Redpolls.

The Greenland race is a very large and pale bird, with the male sometimes described as a “snowball”, but both forms are pale with small beaks, white rumps and often more yellow than grey-brown tones in their plumage. The females are more streaked on their breasts, sides and rumps, but are still pale.

The binomial commemorates the Danish botanist Jens Wilken Hornemann.

The phylogeny has been obtained by Antonio Arnaiz-Villena et al.

From the Cornell Lab of Ornithology in the USA:

How Many Species of Redpolls Are There, Anyway?

Redpolls are tiny, incredibly hardy arctic finches. For most of us, they are longed-for visitors that show up at feeders every few years. When they do, there’s always the hope of finding a pale Hoary Redpoll among the brown, streaky Common Redpolls. But a new look at these birds’ DNA could change all that. Despite differing appearances, they are genetically almost identical. How can that be? Read the full story here.