Denver Magpies
Identification
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. 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 and Habitat
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.
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.
Fun Facts
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 re-nest 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.
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.
Damage Identification
Magpies cause a variety of problems, especially where their numbers are high. Most problems occur in localized areas where loose colonies have concentrated in close proximity to humans.
Magpies can cause substantial damage locally to crops such as almonds, cherries, corn, walnuts, melons, grapes, peaches, wheat, figs and milo . Their damage is greatest in areas where insects and wild mast are relatively unavailable.
Magpies are often found near livestock where they feed on dung-and carrion-associated insects. They also forage for ticks and other insects on the backs of domestic animals. Perhaps the most notorious magpie behavior is the picking of open wounds and scabs on the backs of livestock. If they find an open wound, such as that from a new brand, they may pick at it until they create a much larger wound. The wound may eventually become infected and, in some instances, may kill the animal. Magpies, like ravens, may peck the eyes out of newborn or sick livestock.
Magpies rob wild bird and poultry nests of eggs and hatchlings. Typically, that does not affect wild bird populations except in local areas where limited habitat makes nests easy to find. They can be very destructive to poultry, however, especially during the nesting season when magpie parents are gathering food for their young.
Magpie roosts can be a nuisance because of excessive noise and the odor associated with droppings. During winter, magpies may congregate in loose colonies and form nightly roosts of hundreds after they have migrated southward and to lower elevations. They typically roost in dense thickets or trees.
Legal Status
Magpies are protected as migratory non-game birds under the Federal Migratory Bird Treaty Act. Under the Federal Codes of Regulation (CFR 50, 21.43) it is stated, however, that "a Federal permit shall not be required to control . . . magpies, when found committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers as to constitute a health hazard or other nuisance. . . ." Most state or local regulations are similar, but consult authorities before taking any magpies.
Damage Prevention and Control Methods
Exclusion
Keep young poultry, poultry nests, and vulnerable livestock in covered fenced pens. Netting can be used to protect small areas and valuable crops.
Habitat Modification
Remove nests of offending magpies that are raiding poultry farms. Remove low brush and roost trees in areas where damage is excessive.
Frightening
A frightening program using pyrotechnics, scarecrows, and propane cannons in conjunction with human presence is effective for magpies in most damage situations, especially for roosts and crops.
Repellents
None are registered.
Toxicants
None are registered.
Trapping
Modified Australian crow and circular-funnel traps can be used to help protect heavily damaged crops from a large local population. Proper care of traps and decoy birds is necessary. Use No. 0 and 1 padded-jaw pole traps to take a few offending individuals. Check local, state, and federal laws before trapping.
Call Critter Control today at 1-800-CRITTER
ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (Cooperative Extension Division, Institute of Agriculture and Natural Resources University of Nebraska-Lincoln, United States Department of Agriculture Animal and Plant Health Inspection Service, Animal Damage Control, Great Plains Agricultural Council Wildlife Committee).