Blackbird 2.0

[Tony Phan]

Thecommon blackbird (Turdus merula) is a species of true thrush. It is also called the Eurasian blackbird (especially in North America, to distinguish it from the unrelated New World blackbirds),[2] or simply the blackbird where this does not lead to confusion with a similar-looking local species. It breeds in Europe, western Asia, and North Africa, and has been introduced to Australia and New Zealand.[3] It has a number of subspecies across its large range; a few former Asian subspecies are now widely treated as separate species. Depending on latitude, the common blackbird may be resident, partially migratory, or fully migratory.

The adult male of the common blackbird (Turdus merula merula, the nominate subspecies), which is found throughout most of Europe, is all black except for a yellow eye-ring and bill and has a rich, melodious song; the adult female and juvenile have mainly dark brown plumage. This species breeds in woods and gardens, building a neat, cup-shaped nest, bound together with mud. It is omnivorous, eating a wide range of insects, earthworms, berries, and fruits.

Both sexes are territorial on the breeding grounds, with distinctive threat displays, but are more gregarious during migration and in wintering areas. Pairs stay in their territory throughout the year where the climate is sufficiently temperate. This common and conspicuous species has given rise to a number of literary and cultural references, frequently related to its song.

About 65 species of medium to large thrushes are in the genus Turdus, characterised by rounded heads, longish, pointed wings, and usually melodious songs. Although two European thrushes, the song thrush and mistle thrush, are early offshoots from the Eurasian lineage of Turdus thrushes after they spread north from Africa, the blackbird is descended from ancestors that had colonised the Canary Islands from Africa and subsequently reached Europe from there.[7] It is close in evolutionary terms to the island thrush (T. poliocephalus) of Southeast Asia and islands in the southwest Pacific, which probably diverged from T. merula stock fairly recently.[8]

It may not immediately be clear why the name "blackbird", first recorded in 1486, was applied to this species, but not to one of the various other common black English birds, such as the carrion crow, raven, rook, or jackdaw. However, in Old English, and in modern English up to about the 18th century, "bird" was used only for smaller or young birds, and larger ones such as crows were called "fowl". At that time, the blackbird was therefore the only widespread and conspicuous "black bird" in the British Isles.[9] Until about the 17th century, another name for the species was ouzel, ousel or wosel (from Old English osle, cf. German Amsel). Another variant occurs in Act 3 of Shakespeare's A Midsummer Night's Dream, where Bottom refers to "The Woosell cocke, so blacke of hew, With Orenge-tawny bill". The ouzel usage survived later in poetry, and still occurs as the name of the closely related ring ouzel (Turdus torquatus), and in water ouzel, an alternative name for the unrelated but superficially similar white-throated dipper (Cinclus cinclus).[10]

The icterid family of the New World is sometimes called the blackbird family because of some species' superficial resemblance to the common blackbird and other Old World thrushes, but they are not evolutionarily close, being related to the New World warblers and tanagers.[13] The term is often limited to smaller species with mostly or entirely black plumage, at least in the breeding male, notably the cowbirds,[14] the grackles,[15] and for around 20 species with "blackbird" in the name, such as the red-winged blackbird and the melodious blackbird.[13]

The Central Asian subspecies, the relatively large intermedius, also differs in structure and voice, and may represent a distinct species.[17] Alternatively, it has been suggested that it should be considered a subspecies of T. maximus,[8] but it differs in structure, voice and the appearance of the eye-ring.[17][18]

The common blackbird breeds in temperate Eurasia, North Africa, the Canary Islands, and South Asia. It has been introduced to Australia and New Zealand.[8] Populations are sedentary in the south and west of the range, although northern birds migrate south as far as northern Africa and tropical Asia in winter.[8] Urban males are more likely to overwinter in cooler climes than rural males, an adaptation made feasible by the warmer microclimate and relatively abundant food that allow the birds to establish territories and start reproducing earlier in the year.[21] Recoveries of blackbirds ringed on the Isle of May show that these birds commonly migrate from southern Norway (or from as far north as Trondheim) to Scotland, and some onwards to Ireland. Scottish-ringed birds have also been recovered in England, Belgium, the Netherlands, Denmark, and Sweden.[22] Female blackbirds in Scotland and the north of England migrate more (to Ireland) in winter than do the males[23]

Common over most of its range in woodland, the common blackbird has a preference for deciduous trees with dense undergrowth. However, gardens provide the best breeding habitat with up to 7.3 pairs per hectare (nearly three pairs per acre), with woodland typically holding about a tenth of that density, and open and very built-up habitats even less.[24] They are often replaced by the related ring ouzel in areas of higher altitude.[25] The common blackbird also lives in parks, gardens and hedgerows.[26]

This widespread species has occurred as a vagrant in many locations in Eurasia outside its normal range, but records from North America are normally considered to involve escapees, including, for example, the 1971 bird in Quebec.[27] However, a 1994 record from Bonavista, Newfoundland, has been accepted as a genuine wild bird,[8] and the species is therefore on the North American list.[28]

The male common blackbird defends its breeding territory, chasing away other males or utilising a "bow and run" threat display. This consists of a short run, the head first being raised and then bowed with the tail dipped simultaneously. If a fight between male blackbirds does occur, it is usually short and the intruder is soon chased away. The female blackbird is also aggressive in the spring when it competes with other females for a good nesting territory, and although fights are less frequent, they tend to be more violent.[24]

The bill's appearance is important in the interactions of the common blackbird. The territory-holding male responds more aggressively towards models with orange bills than to those with yellow bills, and reacts least to the brown bill colour typical of the first-year male. The female is, however, relatively indifferent to bill colour, but responds instead to shinier bills.[29]

As long as winter food is available, both the male and female will remain in the territory throughout the year, although occupying different areas. Migrants are more gregarious, travelling in small flocks and feeding in loose groups in the wintering grounds. The flight of migrating birds comprises bursts of rapid wing beats interspersed with level or diving movement, and differs from both the normal fast agile flight of this species and the more dipping action of larger thrushes.[16]

The male common blackbird attracts the female with a courtship display which consists of oblique runs combined with head-bowing movements, an open beak, and a "strangled" low song. The female remains motionless until she raises her head and tail to permit copulation.[24] This species is monogamous, and the established pair will usually stay together as long as they both survive.[16] Pair separation rates of up to 20% have been noted following poor breeding.[30] Although the species is socially monogamous, there have been studies showing as much as 17% extra-pair paternity.[31]

The nominate T. merula may commence breeding in March, but eastern and Indian races are a month or more later, and the introduced New Zealand birds start nesting in August (late winter).[8][25] The breeding pair prospect for a suitable nest site in a creeper or bush, favouring evergreen or thorny species such as ivy, holly, hawthorn, honeysuckle or pyracantha.[32] Sometimes the birds will nest in sheds or outbuildings where a ledge or cavity is used. The cup-shaped nest is made with grasses, leaves and other vegetation, bound together with mud. It is built by the female alone. She lays three to five (usually four) bluish-green eggs marked with reddish-brown blotches,[24] heaviest at the larger end;[25] the eggs of nominate T. merula are 2.9 cm 2.1 cm (1.14 in 0.83 in) in size and weigh 7.2 g (0.25 oz), of which 6% is shell.[33] Eggs of birds of the southern Indian races are paler than those from the northern subcontinent and Europe.[8]

In its native Northern Hemisphere range, the first-year male common blackbird of the nominate race may start singing as early as late January in fine weather in order to establish a territory, followed in late March by the adult male. The male's song is a varied and melodious low-pitched fluted warble, given from trees, rooftops or other elevated perches[37] mainly in the period from March to June, sometimes into the beginning of July. It has a number of other calls, including an aggressive seee, a pook-pook-pook alarm for terrestrial predators like cats, and various chink and chook, chook vocalisations. The territorial male invariably gives chink-chink calls in the evening in an attempt (usually unsuccessful) to deter other blackbirds from roosting in its territory overnight.[24] During the northern winter, blackbirds can be heard quietly singing to themselves, so much so that September and October are the only months in which the song cannot be heard.[38] Like other passerine birds, it has a thin high seee alarm call for threats from birds of prey since the sound is rapidly attenuated in vegetation, making the source difficult to locate.[39]

3a8082e126