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Magpies

The magpie is a highly intelligent bird and very adaptable. They are omnivorous and will nest in most places where there are trees. In urban areas they have been known to use artificial structures such as telephone poles and electricity pylons.

Breeding

Breeding magpies hold a territory of about 5 ha all year round. Because nest sites are limited, up to 60% of magpies in an area do not breed. These non-breeding birds often form flocks with a home range of up to 20 ha.

Magpies usually breed from two years old. They build large, domed nests in thorny bushes or high up in tall trees. An average of six greenish-blue eggs, heavily spotted with brown, are laid in April. The female incubates them for 18 to 19 days. During this time she is fed on the nest by the male. They fledge after 26 to 30 days, and are fed by the parents for a further four weeks after leaving the nest.

The young birds stay in the parents territory until September or October, when they form loose flocks, feeding and roosting together. During the winter, flocks may join to form large winter roosts. Some breeding birds may also join these roosts.

On average, one or two young of each nesting pair survive each year. The highest death rate occurs during the first four months of life: they may be killed by predators like other crows, deserted by their parents, or starve. If the young birds survive this period, their average life expectancy is three years, but some live much longer than this: the oldest recorded is 16 years.

Feeding

Magpies have a strong bill with a sharp cutting edge, which can be used for cutting flesh, digging up invertebrates, or picking fruit. 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, petfoods 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. 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.

Population

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 World War II, 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. In many areas which have been studies, the breeding population is stable but the non-breeding flocks are increasing.

Magpies and Songbirds

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.

Many of the UKs commonest songbirds have declined during the last 25 years, at a time when populations of magpies increased. Studies to date have found that songbird numbers were no different in places where there were many magpies or sparrowhawks 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. It is the availability of food and suitable places in which to nest that decide the population. Other factors such as intensive farming, changes from spring to autumn sowing and the increase in the use of agricultural chemicals which have reduced the amount of insects and weed seeds available for songbirds to eat are all thought to have contributed towards the decline. Other changes, including the removal of hedgerows which are used for nesting, roosting and feeding sites by some birds, have probably also played a part in the severe declines in many of our farmland species.

Legal status

Magpies are fully protected by the European Union Birds Directive. The UK Government has derogated (made an exception) from the Directive in relation to control of magpies. Under annual general licence issued under the Wildlife and Countryside Act 1981 (for which it is not necessary to apply individually), magpies may be killed or taken by authorised persons, using permitted methods, for the purposes of:

  • preventing serious damage to agricultural crops or livestock
  • preserving public health/air safety
  • conserving wild birds.

An authorised person is a landowner or occupier, or someone acting with the landowners or occupiers permission.

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