Urraca Común

Identificación

The adult male of the nominate subspecies, P. p. pica, is 44–46 cm (17–18 in) in length, of which more than half is the tail. The wingspan is 52–62 cm (20–24 in). The head, neck and breast are glossy black with a metallic green and violet sheen; the belly and scapulars (shoulder feathers) are pure white; the wings are black glossed with green or purple, and the primaries have white inner webs, conspicuous when the wing is open. The graduated tail is black, glossed with green and reddish purple. The legs and bill are black; the iris is dark brown. The plumage of the sexes is similar but females are slightly smaller. The tail feathers of both sexes are quite long, about 12–28 cm long. Males of the nominate subspecies weigh 210–272 g (7.4–9.6 oz) while females weigh 182–214 g (6.4–7.5 oz). The young resemble the adults, but are at first without much of the gloss on the sooty plumage. The young have the malar region pink, and somewhat clear eyes. The tail is much shorter than the adults.<p>The subspecies differ in their size, the amount of white on their plumage and the colour of the gloss on their black feathers. The Asian subspecies P. p. bactriana has more extensive white on the primaries and a prominent white rump.<p>Adults undergo an annual complete moult after breeding. Moult begins in June or July and ends in September or October. The primary flight feathers are replaced over a period of three months. Juvenile birds undergo a partial moult beginning about one month later than the adult birds in which their body feathers are replaced but not those of the wings or the tail.<p>Eurasian magpies have a well-known call. It is a choking chatter "chac-chac" or a repetitive "chac-chac-chac-chac". The young also emit the previous call, although they also emit an acute call similar to a "Uik Uik", which may resemble the barking of a small dog. Both adults and young can emit a kind of hiss barely noticeable from afar.

Taxonomía

The magpie was described and illustrated by Swiss naturalist Conrad Gessner in his Historiae animalium of 1555. In 1758, Linnaeus included the species in the 10th edition of his Systema Naturae under the binomial name Corvus pica. The magpie was moved to a separate genus Pica by the French zoologist Mathurin Jacques Brisson in 1760. Pica is the Classical Latin word for this magpie.<p>The Eurasian magpie is almost identical in appearance to the North American black-billed magpie (Pica hudsonia) and at one time the two species were considered to be conspecific. In 2000, the American Ornithologists' Union decided to treat the black-billed magpie as a separate species based on studies of the vocalization and behaviour that indicated that the black-billed magpie was closer to the yellow-billed magpie (Pica nuttalli) than to the Eurasian magpie.<p>The gradual clinal variation over the large geographic range and the intergradation of the different subspecies means that the geographical limits, and acceptance of the various subspecies, vary between authorities. The International Ornithological Congress recognises six subspecies (a seventh, P. p. hemileucoptera, is included in P. p. bactriana):<p>Others now considered as distinct species:<p>A study using both mitochondrial and nuclear DNA found that magpies in eastern and northeastern China are genetically very similar to each other, but differ from those in northwestern China and Spain.<p>Magpies were originally known as simply "pies". This is hypothesized to derive from a Proto-Indo-European root *(s)peyk- meaning "pointed", in reference to the beak or perhaps the tail (cf. woodpecker). The prefix "mag" dates from the 16th century and comes from the short form of the given name Margaret, which was once used to mean women in general (as Joe or Jack is used for men today); the pie's call was considered to sound like the idle chattering of a woman, and so it came to be called the "Mag pie". "Pie" as a term for the bird dates to the 13th century, and the word "pied", first recorded in 1552, became applied to other birds that resembled the magpie in having black-and-white plumage.

Nombre científico

Pica pica

Autoridad

(Linnaeus, 1758)

Orden

Passeriformes

Familia

Córvidos

Género

Pica

Distribución y hábitat

The range of the magpie extends across temperate Eurasia from Portugal, Spain and Ireland in the west to the Kamchatka Peninsula.<p>The preferred habit is open countryside with scattered trees and magpies are normally absent from treeless areas and dense forests. They sometimes breed at high densities in suburban settings such as parks and gardens. They can often be found close to the centre of cities.<p>Magpies are normally sedentary and spend winters close to their nesting territories but birds living near the northern limit of their range in Sweden, Finland and Russia can move south in harsh weather.

Migración

Resident species

Comportamiento

Some magpies breed after their first year, while others remain in the non-breeding flocks and first breed in their second year. They are monogamous, and the pairs often remain together from one breeding season to the next. They generally occupy the same territory on successive years.<p>Mating takes place in spring. In the courtship display, males rapidly raise and depress their head feathers, uplift, open and close their tails like fans, and call in soft tones quite distinct from their usual chatter. The loose feathers of the flanks are brought over the primaries, and the shoulder patch is spread so the white is conspicuous, presumably to attract females. Short buoyant flights and chases follow.<p>Magpies prefer tall trees for their bulky nest, firmly attaching them to a central fork in the upper branches. A framework of the sticks is cemented with earth and clay, and a lining of the same is covered with fine roots. Above is a stout though loosely built dome of prickly branches with a single well-concealed entrance. These huge nests are conspicuous when the leaves fall. Where trees are scarce, though even in well-wooded country, nests are at times built in bushes and hedgerows.<p>In Europe, clutches are typically laid in April, and usually contain five or six eggs, but clutches with as few as three and as many as ten have been recorded. The eggs are laid in early morning, usually at daily intervals. On average, the eggs of the nominate species measure 32.9 mm × 23 mm (1.30 in × 0.91 in) and weigh 9.9 g (0.35 oz). Small for the size of the bird, they are typically pale blue-green, with close specks and spots of olive brown, but show much variation in ground and marking.<p>The eggs are incubated for 21–22 days by the female, who is fed on the nest by the male. The chicks are altricial, hatching nearly naked with closed eyes. They are brooded by the female for the first 5–10 days and fed by both parents. Initially the parents eat the faecal sacs of the nestlings, but as the chicks grow larger, they defecate on the edge of the nest. The nestlings open their eyes 7 to 8 days after hatching. Their body feathers start to appear after around 8 days and the primary wing feathers after 10 days. For several days before they are ready to leave the nest, the chicks clamber around the nearby branches. They fledge at around 27 days. The parents then continue to feed the chicks for several more weeks. They also protect the chicks from predators, as their ability to fly is poor, making them vulnerable. On average, only 3 or 4 chicks survive to fledge successfully. Some nests are lost to predators, but an important factor causing nestling mortality is starvation. Magpie eggs hatch asynchronously, and if the parents have difficulty finding sufficient food, the last chicks to hatch are unlikely to survive. Only a single brood is reared, unless disaster overtakes the first clutch.<p>A study conducted near Sheffield in Britain, using birds with coloured rings on their legs, found that only 22% of fledglings survived their first year. For subsequent years, the survival rate for the adult birds was 69%, implying that for those birds that survive the first year, the average total lifespan was 3.7 years. The maximum age recorded for a magpie is 21 years and 8 months for a bird from near Coventry in England that was ringed in 1925 and shot in 1947.<p>The magpie is omnivorous, eating young birds and eggs, small mammals, insects, scraps and carrion, acorns, grain, and other vegetable substances.<p>Along with other corvids such as ravens, western jackdaws and crows, the Eurasian magpie is believed to be not only among the most intelligent of birds, but also among the most intelligent of all animals. The Eurasian magpie's nidopallium is approximately the same relative size as those in chimpanzees and humans, and significantly larger than those of the gibbons. Their total brain-to-body mass ratio is equal to most great apes and cetaceans. A 2004 review suggests that the intelligence of the corvid family to which the Eurasian magpie belongs is equivalent to that of the great apes (bonobos, gorillas and orangutans) in terms of social cognition, causal reasoning, flexibility, imagination and prospection.<p>Magpies have been observed engaging in elaborate social rituals, possibly including the expression of grief. Mirror self-recognition has been demonstrated in European magpies, making them one of only a few species known to possess this capability. The cognitive abilities of the Eurasian magpie are regarded as evidence that intelligence evolved independently in both corvids and primates. This is indicated by tool use, an ability to hide and store food across seasons, episodic memory, and using their own experience to predict the behavior of conspecifics. Another behaviour exhibiting intelligence is cutting their food in correctly sized proportions for the size of their young. In captivity, magpies have been observed counting up to get food,[clarification needed] imitating human voices, and regularly using tools to clean their own cages.[citation needed] In the wild, they organise themselves into gangs and use complex strategies[examples needed] hunting other birds and when confronted by predators.

Conservación

Tendencia poblacional

stable