Common Blackbird

The common blackbird is a widespread species of true thrush native to Europe, western Asia and North Africa, with introduced populations in Australia and New Zealand. Recognised for its melodious song, territorial behaviour and distinctive plumage, the species is an iconic and familiar component of the avifauna across its range. It exhibits considerable geographical variation and occupies a wide variety of woodland and garden habitats, displaying flexible behavioural patterns that include resident, partially migratory and fully migratory populations depending on latitude and climate.

Taxonomy and Systematics

The species was formally described by Carl Linnaeus in the 1758 Systema Naturae, under the name Turdus merula. Its scientific name derives from Latin, with Turdus meaning ‘thrush’ and merula signifying ‘blackbird’. Historically, the English word ‘blackbird’—first recorded in the late fifteenth century—was applied to this species when the word bird referred mainly to smaller species, while larger ones such as crows were classed as fowl. This distinction explains why the name did not attach to other black-plumaged birds such as ravens or rooks.
The genus Turdus comprises around 65 species characterised by rounded heads, pointed wings and usually tuneful vocalisations. Molecular and biogeographical evidence indicates that the common blackbird originated from ancestral forms that colonised the Canary Islands from Africa before spreading into Europe. It is closely related to the island thrush (Turdus poliocephalus) of Southeast Asia and the Pacific, from which it likely diverged relatively recently in evolutionary terms.
The species has historically been linked with several Asian thrushes labelled locally as blackbirds. Some forms—such as the Indian blackbird (T. simillimus), Tibetan blackbird (T. maximus) and Chinese blackbird (T. mandarinus)—were formerly considered subspecies of T. merula but are now widely treated as distinct species, differing in morphology, distribution and vocalisations. The Somali thrush (T. olivaceus ludoviciae) is occasionally referred to as the Somali blackbird. The New World icterids, despite being called blackbirds in North America, are evolutionarily unrelated, belonging instead to a lineage closer to warblers and tanagers.

Distribution and Migration

The common blackbird occupies a broad Palearctic range, extending from Iceland and the British Isles eastward to the Ural Mountains and from northern Scandinavia south to the Mediterranean and North Africa. Several populations are sedentary where winters are mild, while others migrate seasonally. Birds from northern Europe typically winter around the Mediterranean basin, including North Africa and Cyprus. Introduced populations in Australia and New Zealand have become well established, primarily descending from the nominate subspecies.
Migration strategies vary considerably: northern populations are strongly migratory, whereas temperate populations may defend territories year-round. Birds in mountainous regions sometimes undertake altitudinal movements, wintering at lower elevations where food resources are more reliable.

Behaviour and Ecology

Blackbirds are omnivorous, feeding on earthworms, insects, berries and fruits. They forage mainly on the ground, using characteristic hopping movements and listening for soil vibrations made by invertebrates. The species breeds in woodland edges, hedgerows and gardens, constructing a well-formed, cup-shaped nest bound together with mud and lined with grasses. Clutches typically contain three to five eggs, and multiple broods may be raised in favourable conditions.
Territoriality is strongly marked during the breeding season, with both sexes defending their areas through displays and vocal warnings. Outside the breeding period, individuals become more tolerant and often gather loosely in winter feeding sites or migratory stopover points.
The male’s song is rich, fluting and widely celebrated in literature and folklore. Cultural associations frequently emphasise themes of spring renewal and pastoral tranquillity. Shakespeare, for instance, used the older name “ousel” in his works, and the species continues to feature prominently in European poetry and music.

Subspecies Variation

Given its wide distribution, T. merula is represented by several recognised subspecies differing subtly in size, plumage and vocalisations:

• T. m. merula: The nominate and most widespread form, breeding across much of Europe into western Asia. Northern populations are migratory, while those in temperate areas are largely resident.
• T. m. azorensis: A small, notably dark race local to the Azores, with particularly glossy male plumage.
• T. m. cabrerae: Found in Madeira and the western Canary Islands, resembling azorensis but geographically distinct.
• T. m. mauritanicus: A dark subspecies occurring in Morocco, northern Algeria and northern Tunisia.
• T. m. aterrimus: Distributed from Hungary and southern Europe through Turkey to Iran, wintering farther south into North Africa and the Middle East. It is smaller than the nominate subspecies, with duller males and paler females.
• T. m. syriacus: Occupies coastal regions from southern Turkey to Jordan, Israel and the northern Sinai. Plumage in both sexes is darker and greyer than that of merula.
• T. m. intermedius: A larger Central Asian form breeding from Russia to Afghanistan and China. Some populations are altitudinal migrants. Structural and vocal differences suggest this subspecies could represent a distinct species, though taxonomic treatment varies.

These subspecies reflect adaptations to local environments, from climatic conditions to habitat types and food availability.

Similar Species

In Europe, the common blackbird may be confused with the first-winter ring ouzel (Turdus torquatus), which shows paler wing panels and, in adults, a distinctive white crescent on the breast. The common starling (Sturnus vulgaris) is superficially similar when its plumage appears dark, but it differs in shape, iridescent feathering and flocking behaviour. Comparable species in other continents, such as the South American Chiguanco thrush (Turdus chiguanco), share general coloration but differ in distribution and structural features.

Description

Adults of the nominate subspecies measure around medium size for a thrush, possessing a long tail and moderate body mass typical of Turdus species. The adult male is distinguished by glossy black plumage, blackish-brown legs, a bright yellow eye-ring and a striking orange-yellow bill that becomes darker in winter. The female is predominantly sooty brown with a mottled breast and a dull yellowish-brown bill. Juveniles resemble females but exhibit spotted upperparts and a speckled breast. First-year males show intermediate features, including a dark bill and brown-toned wings that differ from the jet-black adult plumage.
Variation in juvenile plumage intensity can indicate sex, with darker individuals more likely to be males. Moult patterns, eye-ring brightness and bill colouration also assist in determining age and reproductive status.

Behavioural Notes and Cultural Associations

The species’ strong, melodious song and adaptability to human-modified environments have made it a familiar presence in gardens and parks. In temperate regions, pairs may hold territories throughout the year, using vocalisations to signal dominance and boundary ownership. The blackbird’s visibility and vocal prominence have led to its frequent appearance in European folklore, poetry and nursery rhymes, reflecting its status as one of the continent’s most recognisable passerines.