Redwing

The redwing (Turdus iliacus) is a small northern thrush breeding across Iceland, Scandinavia and a broad belt of northern Eurasia. Adults are about 20–24 cm long and usually weigh around 50–75 g. The most distinctive field marks are the broad creamy-white eyebrow stripe and rusty-red flanks and underwing coverts, contrasting with brown upperparts and a pale, streaked breast. Males and females look very similar.

The fieldfare (Turdus pilaris) is larger and greyer, while the song thrush (Turdus philomelos) lacks the strong eyebrow stripe and has more arrow-shaped breast spots. Birds of the Icelandic and Faroese subspecies T. i. coburni are on average darker and somewhat larger than nominate iliacus from continental Eurasia.

During breeding, redwings favour birch, mixed and deciduous woodland, forest edges, scrub and other structurally varied habitats with shrubs and open feeding ground nearby. Across the northern part of the range they also breed in relatively open birch woodland and willow scrub close to the treeline.

Outside the breeding season they use a much broader range of open habitats, including pasture, farmland, orchards, hedgerows and woodland edges. The availability of fruiting trees and shrubs can strongly influence where large winter flocks concentrate.

Earthworms, insects, snails and other invertebrates dominate the diet during spring and summer and are important food for the young. Redwings forage extensively on the ground, probing and picking prey from soil, short vegetation and leaf litter.

In autumn and winter the diet shifts strongly towards berries and fruit. Rowan is especially important in northern Europe, together with hawthorn and other fruit-bearing trees and shrubs. Rich crops can attract large flocks, often mixed with fieldfares and other thrushes.

Redwing song is short and relatively simple, but its structure varies strikingly between local populations. A classic study from 1971–1977, conducted roughly 40 km north of Oslo, documented sharply bounded local song dialects that remained highly consistent between years. Males living near dialect boundaries sometimes used elements from both neighbouring song types.

The species also gives a thin, penetrating flight call that is especially conspicuous during nocturnal migration, when passing birds may be heard long after dark even when they cannot be seen.

Most redwings breeding in northern and eastern parts of the range migrate south and west in autumn. Many Scandinavian birds winter in western and southern Europe, including Britain, France, the Iberian Peninsula and the Mediterranean region. Much of the migration takes place at night.

A 41-year study from southern Norway, covering 1980–2020, showed how flexible winter movements can be. In eastern Norway, winter numbers were highest in years with abundant rowan berries, while winter weather alone explained much less. Harsh conditions intensified the effect when berries were scarce. Some birds can therefore remain much farther north in food-rich winters, whereas poor berry crops promote larger southward movements.

Breeding begins in spring, with timing becoming progressively later toward the north and at higher elevations. The female builds a substantial cup nest of grass, moss and other plant material, often reinforced with mud. Nests are commonly placed low in a tree or shrub but may also occur on stumps, banks or close to the ground.

A typical clutch contains 4–5 blue-green eggs. The female incubates for about 11–15 days, while both parents feed the chicks. The young normally leave the nest after about 10–15 days and remain dependent on the adults for a period afterwards. Two broods are common where the season is long enough.

The redwing is classified as least concern on the IUCN Red List. After being assessed as near threatened in 2015, it returned to least concern in the 2025 Red List update.

The 2025 update from the Pan-European Common Bird Monitoring Scheme, based on data through 2024, shows a 31% decline in the European breeding index from 1980 to 2024, but a 4% increase in 2015–2024. The recent improvement therefore sits within a substantial long-term decline.

Redwings also move widely between years in response to food availability, so winter numbers in one locality can change greatly without directly reflecting the wider breeding population.