Blackbird Factfile

Blackbird identification

The Blackbird is one of the easiest garden birds to identify. The adult male Blackbird is black, and has a bright yellow bill (though this colour is not evident in younger birds). The female is dark brown, with pale brown streaks and mottling on its breast.

Adult male birds have a distinct and bright yellow eye ring. This is much less bright in females – which also applies to the female’s bill. Both sexes are about the same size, with a wingspan of between 34cm and 38.5cm.

A slightly confusing aspect to the identification of male Blackbirds, is that they are not born with their yellow eye ring. This usually becomes visible late in the winter or early spring the year after they are born. Additionally, their black plumage also takes time to develop. Indeed, when male Blackbirds fledge — and for some time after — they look much like females.

Given this, a male Blackbird coming into its first winter will likely have developed back plumage but won’t yet have a yellow bill or yellow eye ring. A further factor in the timing of the change in plumage colour will be how early in the season the bird was born. This means there is a considerable time difference between an early brood in March or April, compared to a late and possible forth brood in August.

Related birds

The Blackbird is a member of the thrush family. Despite this, there are no other garden birds it can be confused with. Away from gardens and in upland areas or elsewhere during migration, the now very rare Ring Ouzel could be confused for a Blackbird. However, the white crescent shaped band on the breast of the male Ring Ouzel is diagnostic.

What sound does a Blackbird make?

Blackbirds have an especially appealing and melodic bird song, with the male bird delivering this from an exposed perch from late winter onwards when the breeding season starts. The male Blackbird song is to initially attract a mate and to proclaim a territory, then just the latter once a mate is attracted. Blackbirds are one of the first birds in the morning to start the dawn chorus and usually the last birds singing in the evening.

Blackbirds – both male and female – also have loud alarm calls, with these given when they see or sense danger such as a cat walking through a garden. These alarm calls can be roughly categorised into three sounds. A Blackbird’s alarm call will also get a reaction from other garden bird species, which normally will also take cover when they hear it.

What sound does a Blackbird make?

Video footage of Blackbirds

Blackbird nesting and breeding habits

Blackbirds, which are members of the thrush family, are very territorial in nature. If other blackbirds encroach on their breeding territory they are quick in trying to remove them from their patch.

The species make their substantial nest from mixed plant materials combined with some mud for reinforcement, with only the female doing the building. The location is usually in fairly thick vegetation such as a hedgerow, though they will sometimes use an open-fronted next box provided it is well concealed (perhaps in a wall climbing plant). Breeding starts in March, with between two and three clutches being usual, though sometimes a fourth brood is attempted with the chicks still in the nest well into August. Weather is the major factor which determines the number of broods and their success, with cold, dry springs often delaying or hindering the first brood, and hot dry summers preventing a third or forth brood. In both cases, the lack of earthworms close to the surface of the ground is the main problem.

The female incubates the eggs alone – there are normally 3-5 eggs – and also broods the young chicks alone. However, the male Blackbird takes its full share in feeding of the young – both in the nest and once they leave it.

When the young Blackbirds first leave the nest at about thirteen to fourteen days old, they are unable to fly and instead flutter around in nearby undergrowth for safety and waiting to be fed by the parent birds. This is a critical time for the birds and a good percentage don’t survive, but actually the evolved adaptation of leaving the nest early is a good overall defense against predators, as it means the young aren’t all in one exact location. A week after leaving the nest, the young fledge and are therefore able to fly – albeit initially not terribly well.

Once the young have fledged, the female stops feeding them and only the male continues for a further two weeks or so, as the young progressively become more independent. The reason the female stops is so she can start the next clutch of eggs.

Blackbird history and population trends

Having declined substantially during the 1970s and through to the mid-1990s, the species has since bounced back and continues to do well. Indeed, its status has moved from amber to green. It’s highly likely that the increasing popularity of people putting out high quality bird food such as sunflower hearts in their gardens, is one of the reasons the Blackbird population has improved in recent decades.

Behaviour traits of Blackbirds

Blackbirds are largely solitary in their behaviour, with interaction with others of the same species being limited – except of course for breeding and when the young are born. Outside the breeding season there is a greater tolerance, and during the winter months loose groups of up to twenty birds can be seen together and including roosting at night. However, close proximity to each other is avoided, with a sense of an uneasy alliance formed and for the sake of safety in numbers only.

Interestingly, adult male Blackbirds tolerate their young in their territory for a few weeks after the young have become independent, which is normally three weeks after they leave the nest. The young anyway then disperse away from the breeding area on their own accord.

The male Blackbird establishes a territory in its first winter, and although it will stray from this to feed – and often very long distances in search of food in the winter months – it will always return to the same territory to breed throughout its life. The strong territorial instinct and intolerance of others from the same species (even outside territories) when feeding is central to Blackbird behaviour, and indeed it can especially be observed in gardens in the winter months when multiple Blackbirds appear in almost continual conflict with each other. That said, the conflict can be minimised in larger gardens by ensuring that food is spread out – e.g. sunflower hearts scattered on a lawn or large patio. This gives the Blackbirds what they no doubt see as a ‘safe distance’ and a degree of tolerance between them is then evident.

Blackbird diet and food

Earthworms and a huge variety of insects are staple foods for the Blackbird, along with berries and fruit when they’re in season. Indeed, the ability to switch to very different foods as the seasons change is part of the Blackbird’s success, which is another reason they take so readily to food put out for them in gardens.

A further factor which determines diet during the breeding season is location. Blackbirds that nest in native woodland mainly take caterpillars – both for their own food and what they feed to their young. This contrasts to Blackbirds which nest in more urban areas, including gardens, where the primary food tends to be earthworms.