Information about the Magpie

The Magpie

With its noisy chattering, black-and-white plumage and long tail, there is nothing else quite like the magpie in the UK. When seen close-up its black plumage takes on an altogether more colourful hue with a purplish-blue iridescent sheen to the wing feathers and a green gloss to the tail.

Magpies seem to be jacks of all trades - scavengers, predators and pest-destroyers, their challenging, almost arrogant attitude has won them few friends. Non-breeding birds will gather together in flocks.

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Many of the UK's commonest songbirds have declined during the last 25 years, at a time when populations of magpies increased.
 

Why songbirds might be affected by magpies

Most British members of the crow family (including magpies) will take eggs and nestlings. This can be upsetting to witness but it is completely natural. However, some people are concerned that there may be a long-term effect on songbird populations.

To find out why songbirds are in trouble, the RSPB has undertaken intensive research on species such as the skylark and song thrush. To discover whether magpies could be to blame for the decline, the RSPB commissioned the British Trust for Ornithology (BTO) to analyse its 35 years of bird monitoring records.

The study found that songbird numbers were no different in places where there were many magpies from where there are few. It found no evidence that increased numbers of magpies have caused declines in songbirds and confirms that populations of prey species are not determined by the numbers of their predators. Availability of food and suitable nesting sites are probably the main factors limiting songbird populations.

Breeding magpies

Breeding magpies hold a territory of about five hectares (12 acres) all year round. Because nest sites are limited, between 25 per cent and 60 per cent of magpies in an area do not breed. These non-breeding birds often form flocks with a home range of up to 20 hectares (about 50 acres) and may pair up within the flock.

Magpies usually breed from two years old, although some may breed at one year. They build large, domed nests in thorny bushes or high up in tall trees.

The female lays on average six greenish-blue eggs, heavily spotted with brown, in April, and incubates them for 18 to 19 days. During this time the male feeds her on the nest. Incubation starts in the middle of the laying period, so the earliest eggs hatch first.

The changes in magpie numbers

Until the mid-19th century, magpies were very common in Britain and were popular with farmers because they eat harmful insects and rodents. But from then until the First World War, heavy persecution by gamekeepers caused their numbers to plummet.

Since the Second World War, magpie numbers have increased. Their numbers trebled from 1970 to 1990, since when they have become more stable. Urban and suburban magpies increased much faster than rural populations. In towns they are not persecuted, there is more food available, magpies will nest close to people, which protects their nests from crows, and they can breed earlier in the year because towns are warmer than the surrounding countryside.

Urban magpies will use artificial nest sites and nest materials, and will take food from bird tables, sometimes storing it in man-made structures such as gutters and eaves.

Factors that normally limit magpie populations are lack of nesting territories and high mortality of young birds. The relatively stable population since 1990 suggests that magpies have reached an ecological equilibrium.

The diet of a magpie

Their main diet in summer is grassland invertebrates, such as beetles, flies, caterpillars, spiders, worms and leatherjackets.

In winter, they eat more plant material, such as wild fruits, berries and grains, with household scraps and food scavenged from bird tables or chicken runs, pet foods etc. They will eat carrion at all times and catch small mammals and birds. Occasionally, magpies prey on larger animals such as young rabbits.

During the breeding season they will take eggs and young of other birds. We don't know exactly what proportion of the summer diet of urban and suburban magpies these comprise: estimates vary between 3 per cent and 38 per cent by weight, although most estimates are at the low end of this scale. Studies of urban magpies in Manchester showed a summer diet mostly of invertebrates with some field voles and house sparrows.

When food is abundant, magpies hoard the surplus to eat later. They make a small hole in the ground with their beak, place the food in it and cover it with grass, a stone or a leaf. These caches are spread around their territory or home range.