The Blackbird (Turdus merula), is one of the most common birds in the UK. It mainly eats worms and insects as well as fruits and berries when they are in season. It may also make occasional visits to bird tables. Its frequent behaviour can be seen by it turning over leaves beneath trees and other plants looking for food. The nest is mainly built by the female and she will use dry grass , twigs and moss and she will line the nest with dry grass. The female will usually lay three to 4 eggs and these are incubated for two weeks. The young leave the nest two weeks later but will still be dependant on their parents.
The Common Blackbird of the nominate subspecies T. m. merula is 23.5 to 29 centimetres (9.25 to 11.4 in) in length, has a long tail, and weighs 80–125 grammes (2.8 to 4.4 oz). The adult male has glossy black plumage, blackish-brown legs, a yellow eye-ring and an orange-yellow bill. The bill darkens somewhat in winter. The adult female is sooty-brown with a dull yellowish-brownish bill, a brownish-white throat and some weak mottling on the breast. The juvenile is similar to the female, but has pale spots on the upperparts, and the very young juvenile also has a speckled breast. Young birds vary in the shade of brown, with darker birds presumably males. The first year male resembles the adult male, but has a dark bill and weaker eye ring, and its folded wing is brown, rather than black like the body plumage.
Distribution and habitatEdit
The Common Blackbird breeds in temperate Eurasia, North Africa, the Canary Islands, and South Asia. It has been introduced to Australia and New Zealand. 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. 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.
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. They are often replaced by the related Ring Ouzel in areas of higher altitude.
The Common Blackbird occurs up to 1000 metres (3300 ft) in Europe, 2300 metres (7590 ft) in North Africa, and at 900–1820 metres (3000–6000 ft) in peninsular India and Sri Lanka, but the large Himalayan subspecies range much higher, with T. m. maximus breeding at 3200–4800 metres (10560–16000 ft) and remaining above 2100 metres (6930 ft) even in winter.
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. However, a 1994 record from Bonavista, Newfoundland has been accepted as a genuine wild bird, and the species is therefore on the North American list.
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.
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.
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.
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. This species is monogamous, and the established pair will usually stay together as long as they both survive. Pair separation rates of up to 20% have been noted following poor breeding. Although socially monogamous, there have been studies showing as much as 17% extra pair paternity.
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. 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, and the female builds a neat cup-shaped nest from grasses and similar vegetation, which she then lines with mud or muddy leaves. She lays three to five (usually four) bluish-green eggs marked with reddish-brown blotches, heaviest at the larger end; the eggs of nominate T. merula are 2.9 x 2.1 centimetres (1.14 x 0.93 in) in size and weigh 7.2 grammes (0.25 oz), of which 6% is shell. Eggs of birds of the southern Indian races are paler than those from the northern subcontinent and Europe. The female incubates for 12–14 days before the altricial chicks are hatched naked and blind. Fledging takes another 10–19 (average 13.6) days, with both parents feeding the young and removing faecal sacs. The young are fed by the parents for up to three weeks after leaving the nest, and will follow the adults begging for food. If the female starts another nest, the male alone will feed the fledged young. Second broods are common, with the female reusing the same nest if the brood was successful, and three broods may be raised in the south of the Common Blackbird's range.
Montane subspecies, such as T. merula maximus have a shorter breeding season, smaller clutches (2–4 eggs, averaging 2.86), but larger eggs than nominate merula. They produce just one brood per year, and have a slightly shorter incubation period of 12–13 days, but a longer nestling period (16–18 days).
A Common Blackbird has an average life expectancy of 2.4 years, and, based on data from bird ringing, the oldest recorded age is 21 years and 10 months.
The Common Blackbird is omnivorous, eating a wide range of insects, earthworms, seeds and berries. It feeds mainly on the ground, running and hopping with a start-stop-start progress. It pulls earthworms from the soil, usually finding them by sight, but sometimes by hearing, and roots through leaf litter for other invertebrates. Small vertebrates such as frogs, tadpoles and lizards are occasionally hunted. This species will also perch in bushes to take berries and collect caterpillars and other active insects. Animal prey predominates, and is particularly important during the breeding season, with windfall apples and berries taken more in the autumn and winter. The nature of the fruit taken depends on what is locally available, and frequently includes exotics in gardens. In northern India, banyan and mulberry fruits are frequently eaten, with Erythrina and Trema species featuring further south.
Voice: 'chack' call Similar species: Ring Ouzel