Formerly included in the genus Carduelis. This is a juvenile Common Redpoll lacking the red forehead of adults. Note the buff wing-bars characteristic of juveniles. They quickly molt out of this plumage into an adult female-like plumage during late summer/early fall. The breeding population of Redpolls in Iceland is controversial. Most are large and dark, similar to A. f. rostrata from Greenland, Baffin Island, and Northern Labrador, but with shorter bill and wings, and paler rump. Although considered a synonym of rostrata by HBW, IOC and H&M4, Amouret et al. (2015) found them to be identifiable as a valid subspecies following Amadon's 75% rule. A recent genetic study (Mason & Taylor, 2015) found that all redpolls were similar in genetics. Their study found Redpoll phenotypic variation is a result of RNA expressing plumage differences without differences in DNA. They advocate lumping all the Redpolls into a single species. The AOS check-list committee reportedly voted to adopt their suggestion but the change has not been published because of concern over reports of assortative mating between the putative species. Canon SX50 HS PowerShot.
References:
Amouret, J., Steinauer, K., Hallgrimsson, G.T. & Pálsson, S. (2015) Evolutionary status of Icelandic Redpolls Carduelis flammea islandica (Aves, Passeriformes, Fringillidae). J. Orn. 156(4): 1035–1048. https://doi.org/10.1080/00063657.2015.1125850
Clement, P. (2018). Redpoll (Acanthis flammea). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/61363 on 10 September 2018).
Knox, A. G. and P. E. Lowther (2000). Common Redpoll (Acanthis flammea), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.543
Mason, N.A. & Taylor, S.A. (2015) Differentially expressed genes match bill morphology and plumage despite largely undifferentiated genomes in a Holarctic songbird. Mol. Ecol. 24(12): 3009–3025.