MAGPIES BIOLOGY

Thomas C. Hall Fig. 1. North American magpie (Pica pica)
Wildlife Biologist
USDA-APHIS-Wildlife Services
7104 Bellrose Aveneu, NE
Olympia, WA 98502

For additional information click Magpies

Fig. 1. North American magpies; (a)Black-billed magpie Pica pica; (b) Yellow-billed magpie, P.nuttalli

Identification

Magpies have lived in close association with humans for centuries. They are found throughout the Northern Hemisphere and are a common bird of tales and superstitions. Magpies and their many brash behaviors are the basis for the cartoon characters Heckyl and Jeckyl.

Magpies are members of the corvid family, which also includes ravens, crows, and jays. They are easily distinguished from other birds by their size and striking black and white color pattern. They have unusually long tails (at least half of their body length) and short, rounded wings. The feathers of the tail and wings are iridescent, reflecting a bronzy-green to purple. They have white bellies and shoulder patches and their wings flash white in flight. Like other corvids, they are very vocal, even boisterous. Typical calls include a whining “maag” and a series of loud, harsh “chuck” notes. Where magpies are not harassed, they can be extremely bold. If hunted or harassed, though, they become elusive and secretive.

Two distinct species are found in North America, the black-billed and yellow-billed magpies (Fig. 1). They are easily separated by bill color, as their names imply, and by geographic location. Black-billed magpies average 19 inches (47 cm) in length and 1/2 pound (225 g) in weight. They have black beaks and no eye patches. Yellow-billed magpies are somewhat smaller (17 inches [42 cm]) and weigh slightly less than 1/2 pound (225 g). Their bills and bare skin patches behind their eyes are bright yellow.

Range

Magpies are found in western North America. Ranges of the two species do not overlap. Black-billed magpies are found from coastal and central Alaska to Saskatchewan, south to Texas, and west to central California, east of the Sierra-Cascade range. They migrate in winter to lower elevations, and in northern parts of their range, south to areas within their breeding range. Occasionally they wander to areas further east and south of their normal range.

Yellow-billed magpies are residents of the Sacramento and San Joaquin valleys of central California and range south to Santa Barbara County. They do not wander outside of their normal range as often as black-billed magpies, but they have been found in extreme northern California.

Habitat

Magpies are associated with the dry, cool climatic regions of North America. They are typically found close to water in relatively open areas with scattered trees and thickets. The black-billed magpie inhabits foothills, ranch and farm shelterbelts, sagebrush, streamside thickets, parks, and in Alaska, coastal areas. The yellow-billed magpie inhabits farmlands, stream groves, and areas with scattered oaks or tall trees. Their range coincides with a few species of mistletoe that are often used in building their nests.

Food Habits

Magpies are omnivorous and very opportunistic, a characteristic typical of other corvids. They have a preference for animal matter, primarily insects, but readily take anything that is available. Congregations of magpies can commonly be seen along roadsides feeding on animals killed by cars or in ripening fruit and nut orchards. They also pick insects from the backs of large animals and were historically associated with large herds of bison. Their diet changes during the year, reflecting the availability of foods during the different seasons.

The black-billed magpie’s diet typically consists of over 80% animal matter: insects, carrion, small mammals, small wild birds, hatchlings, and eggs. The remainder of its diet consists of fruits and grains. The yellow-billed magpie’s diet is about 70% animal matter and 30% fruits, nuts, and grains. Nestling magpies are fed a diet of mostly animal matter, primarily insects.

Magpies often store or cache food items in shallow pits that they dig in the ground. This behavior is commonly observed in winter, but can be seen throughout the year.

General Biology, Reproduction, and Behavior

Magpies, like other corvids, are intelligent birds. They learn quickly and seem to sense danger. They are boisterous and curious, but shy and secretive in the presence of danger. They mimic calls of other birds and can learn to imitate some human words. They have readily adapted to the presence of humans and have taken advantage of new food sources provided.

Magpies are gregarious and form loose flocks throughout the year. Pairs stay together yearlong, but mates are replaced rapidly if one is lost. Nest building typically begins in early March for black-billed magpies and earlier for yellow-billed magpies. Black-billed magpies build large nests, sometimes 48 inches (125 cm) high by 40 inches (100 cm) wide, made of sticks in low bushes or in trees usually within 25 feet (7.5 m) from the ground. The nest chamber is a cup lined with grass and mud, and normally enclosed by a canopy of sticks. Two entrances are common. Yellow-billed magpies build similar nests, but theirs often resemble mistletoe clumps, which are common in trees where they nest. Magpie nests are usually found in small colonies. Magpies nest once a year, but will renest if their first attempt fails. Other species of birds and mammals often use magpie nests after they have been abandoned.

Black-billed magpies lay 6 to 9 eggs, whereas yellow-billed magpies lay 5 to 8. Incubation normally starts in April, except further north where it may begin as late as mid-June. The incubation period is 16 to 18 days and young are able to fly 3 to 4 weeks after hatching. Young forage with the adults and then join other groups in summer to form loose flocks. Winter congregations may include more than 50 individuals. Yellow-billed magpies, though, may form nightly roosts of 50 or more soon after nesting.

Magpies are not swift fliers. They elude predators and danger by flitting in and out of trees or diving into heavy cover. They usually stay near cover, but often forage in open areas on the ground. Like other corvids, magpies walk with a strut and hop quickly when rushed. They are found close to water, using it for drinking and bathing.

Editors

Scott E. Hygnstrom; Robert M. Timm; Gary E. Larson

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PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994

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