Lesser Redpoll vs Arctic Redpoll

In short

Lesser Redpoll and Arctic Redpoll are notoriously tricky to separate, especially in the field, but the most reliable mark is overall paleness: Arctic Redpoll is much paler and frostier, with a whiter ground color and less streaking, especially on the rump and underparts. Lesser Redpoll is browner and more heavily streaked, with a buffier face and flanks. Structural differences are subtle, but Arctic Redpoll often looks fluffier and bulkier, with a smaller bill. Both have a red forehead and black bib, so focus on the extent of white versus brown and the pattern of streaking, especially on the rump and flanks. Immature and winter birds are the most challenging; careful attention to these marks is essential.

Identification tips

1. Overall paleness: Arctic Redpoll is much paler and frostier than Lesser Redpoll at all ages and seasons. Look for a white ground color on the face, underparts, and especially the rump.
2. Rump pattern: Arctic Redpoll usually has a white or nearly unmarked rump, sometimes with just faint streaks. Lesser Redpoll always shows a streaked, brownish rump. This is one of the most reliable field marks, especially in flight or when the bird is preening.
3. Flank streaking: Lesser Redpoll has heavy, dark streaks on the flanks; Arctic Redpoll's flanks are much less streaked, often appearing clean white or with only faint marks.
4. Face and ear coverts: Lesser Redpoll has a buffier, warmer-toned face and ear coverts, while Arctic Redpoll's face is whiter and contrasts more with the black bib.
5. Bill size and shape: Arctic Redpoll has a smaller, more conical bill, often appearing 'pushed-in' compared to the slightly longer, finer bill of Lesser Redpoll. This is subtle and best used in close views.
6. 'Frosty' appearance: Arctic Redpoll often looks fluffed-up, with loose, pale feathering giving a frosty look, especially around the head and upperparts. Lesser Redpoll is tighter-feathered and browner overall.
7. Wingbars: Both have two pale wingbars, but Arctic Redpoll's can look broader and cleaner due to the paler feather edges.
8. Red on breast: Male Lesser Redpoll often shows more extensive red suffusion on the breast than Arctic Redpoll, but this is variable and unreliable, especially in females and immatures.
9. Juvenile/first-winter birds: Even at this age, Arctic Redpoll is paler and less streaked, with a whiter rump and flanks. Lesser Redpoll juveniles are browner and more heavily streaked.
10. Flight views: In flight, focus on the rump and overall paleness; Arctic Redpoll's white rump and flanks can be striking if seen well.
11. Habitat context: In New Zealand, only Lesser Redpoll occurs. In northern tundra or taiga in summer, Arctic Redpoll is more likely, but in winter both may occur together in Europe and Asia.
12. Flock composition: Both species may occur in mixed flocks, so check each individual carefully; do not assume all redpolls in a flock are the same species.
13. Pitfalls: Light conditions, feather wear, and individual variation can make Lesser Redpolls appear paler or Arctic Redpolls appear darker. Always use a combination of marks, not a single feature.
14. Sex and season: Females and immatures are less colorful and more difficult to separate; rely on structure and streaking rather than red suffusion.
15. Not size alone: Do not use size as a primary mark; overlap is too great for reliable separation.

Size

Both species are small finches, but Arctic Redpoll is generally slightly larger and bulkier than Lesser Redpoll. However, this difference is subtle and often unreliable in the field, especially without direct comparison. Both fall within the same general size range (11.5–14 cm length, 12–16 g mass, 19–22 cm wingspan) [wikipedia], so do not rely on size alone for identification.

Plumage

For all ages, Arctic Redpoll is much paler overall, with a frosty white appearance, especially on the rump, flanks, and underparts. Lesser Redpoll is browner and more heavily streaked, with a buffier face and flanks. The rump is a key area: Arctic Redpoll typically has a white or nearly unmarked rump (sometimes with only faint streaks), while Lesser Redpoll shows a streaked, brownish rump. Both have a red forehead and black bib, but the red on the breast is more extensive in male Lesser Redpoll. Juvenile and first-winter birds of both species can be difficult, but Arctic Redpoll juveniles are still paler and less streaked than Lesser Redpoll of the same age. In flight, both show two pale wingbars, but Arctic Redpoll's wing and tail edges may appear cleaner and more contrasting due to the paler feather edges.

Behaviour

Both species forage mainly in trees for seeds, especially birch and alder, and sometimes feed on the ground. Flocking behavior is similar, and both can be seen in mixed-species flocks in winter. Arctic Redpoll may appear slightly more sluggish or fluffed-up due to its denser plumage, but this is subtle and not a reliable field mark.

Habitat

Habitat overlap is extensive in winter, especially in areas where Arctic Redpoll irrupts southward. Lesser Redpoll is more common in temperate and lowland habitats, including woodlands, parks, and gardens, while Arctic Redpoll breeds farther north in tundra and taiga and is mainly a winter visitor farther south. In New Zealand, only Lesser Redpoll is present. In Europe and Asia, context may help, but habitat alone is not diagnostic where both occur.