Black-billed magpies are medium-sized birds that have tails that are almost as long as their bodies. They are 45 to 60 cm long, and their wingspan is 56 to 61 cm. They weigh 145 to 210 g. They have black feathers on their head, upper breast, back, and tail, and large white patches on their wings and lower chest. They have heavy black bills and black legs. From far away, they look mostly black and white. On their tail, body, and wings, they have shiny patches of iridescent color that look bronze or green in the light. Females are about 10% smaller than males, but their feathers are the same color. Their closest relatives in North America are yellow-billed magpies, but those birds have yellow bills and only live in California. (Birkhead, 1991; Lee, et al., 2003)
Black-billed magpies live in western North America. They are found from northwestern Alaska, through the prairies of Canada, and south to northern Arizona, New Mexico, and western Texas. They avoid summer heat in the desert south, humid weather in the east, and pine forests in the north. (Birkhead, 1991; Linsdale, 1937; Trost, 2009)
Black-billed magpies live in many kinds of habitats like grasslands, woodlands, shrublands, wetlands, deserts, and savanna. They live around woods or open fields, and usually close to water. They need trees or lots of shrubs to build nests in and give them shelter from predators. They search for food in meadows and clearings. They often end up at the edge of different habitats or alongside a river or lake. They also live on farms and around humans. They live at elevations above sea level of 3,000 m. They don't migrate between a summer and winter location, but do move around after breeding and in the winter. Some groups of them move several hundred kilometers. (Birkhead, 1991; Linsdale, 1937; Salt and Salt, 1976)
Black-billed magpies form pairs of one male and one female during the breeding season. In some places, these pairs may last for life. In other places, mates change almost every year. During courtship, males flash their wings and flare their tails. Females call loudly. Males guard their mates from competing males. (Alsop, 2002; Birkhead, 1991; Dhindsa and Boag, 1991; Erpino, 1968; Trost, 2009)
Black-billed magpies breed from late March to early June, depending on where they live. They usually have one set of chicks per season, but will have a second set if something happens to the first. Females lay about 6 eggs or as many as 9. The eggs are greenish-gray with brown markings. They are 3.3 by 2.3 cm long and shaped like ovals. The first egg hatches within 25 days, and usually one chick hatches each day for the next few days. Chicks are born with no feathers and their eyes stay shut for the first 7 days. They can fly in 24 to 30 days after they hatch. The parents feed the chicks for the first 3 to 4 weeks. The young begin to fend for themselves by week 6 or 8, and are independent of their parents after about 70 days. Females usually build a nest in the first year, but males usually don't for 2 or 3 years. (Buitron, 1983; Buitron, 1983; Dhindsa and Boag, 1991; Trost, 2009)
Males and females work together for 5 to 7 weeks to build an elaborate nest shaped like a dome. Males work on building the dome part, which is 60 to 120 cm high. Meanwhile, females build the egg bowl, which is a mud cup at the bottom. The egg bowl is lined with hair, grasses, bark strips, bits of roots, and feathers. Females are mostly responsible for defending the nest before and during egg laying. Then, males take over defending the nest while the female protects the eggs. Like their relatives, only females keep the eggs warm. They rely on the males to bring them food while they are keeping the eggs warm. The parents each play an important and specialized role, so the chicks don't survive if one of the parents dies. After the chicks hatch, males and females both gather food from them. They continue feeding their young for much longer after hatching than crows. This time with the parents might help teach the young how to recognize danger and how to deal with predators. (Birkhead, 1991; Buitron, 1983; Buitron, 1988; Erpino, 1968; Trost, 2009)
Male black-billed magpies live 3.5 years on average, and females live 2 years on average. The record for the oldest black-billed magpie found in the wild was 15 years and 1 month old. The longest known lifespan in captivity of a black-billed magpie was 20 years. (Birkhead, 1991; Cramp and Perrins, 1994; Linsdale, 1937)
Black-billed magpies walk upright, looking confident. They often hop before flying. They fly with slow, steady wing beats. To return to the ground, they alternate short wing flaps with pauses where they tuck their wings into their body. This gives their flight a J-shape. (Alsop, 2002; Birkhead, 1991; Reebs, 1987; Reese and Kadlec, 1985; Stone and Trost, 1991; Trost, 2009)
Sometimes black-billed magpies gather around the bodies of other dead magpies, like they are having a funeral. Scientists aren't sure why they do this. Another interesting thing they can do that similar birds can't is flip things over using their bill or foot. (Crosbie, et al., 2008; Miller and Brigham, 1988; Trost, 2009)
Black-billed magpies are social birds. They live in family flocks made up of 6 to 10 birds. Outside of the breeding time, they make groups that can have several hundred birds. When it's cold outside, they spend time in pine trees to get away from the wind and from predators. (Alsop, 2002; Birkhead, 1991; Reebs, 1987; Reese and Kadlec, 1985; Stone and Trost, 1991; Trost, 2009)
Black-billed magpies can nest by themselves, or in areas with lots of nests all together. They are more likely to nest together when there's lots of food around. This means that they are territorial, but not always. They defend their territory by sitting quietly in the tops of trees to show that they're there. (Alsop, 2002; Birkhead, 1991; Reebs, 1987; Reese and Kadlec, 1985; Stone and Trost, 1991; Trost, 2009)
In the breeding season, black-billed magpies have a territory that is usually about .3 hectares in size.
Black-billed magpies are very smart birds, like many of their relatives. If raised by humans from a young age, they can learn a few words and phrases. In the wild, they use two different kidns of alarm calls. A basic alarm is a harsh rattling that changes depending on the type of danger, and may lead to a group of magpies attacking a predator together. A staccato alarm is a quicker and more excited noise. It probably tells other black-billed magpies to get away from a dangerous predator. Their relatives European magpies make a lot of different sounds, and more research about black-billed magpies might show that they make other sounds as well. (Buitron, 1983; Dice, 1917; Trost, 2009)
Like many of their relatives, black-billed magpies will eat different kinds of animal and plant foods depending on what is available. They look for food on the ground. Scientists can easily figure out what they eat because they spit parts of the food back up after they eating. They mostly eat insects and their young, and the eggs or chicks of songbirds. They also eat fruit and grains, and small mammals like mice and meadow voles. They feed on dead animals like roadkill or trash from humans. They also dig in the ground or snow to store food. (Hall, 1994; Sept, 2004)
Black-billed magpies are eaten by American crows, common ravens, great horned owls, northern harriers, red-tailed hawks, Swainson’s hawks, weasels, mink, domestic cats, raccoons, coyotes, and red squirrels. The mammals that eat them and also American crows are most likely to eat eggs or chicks. Birds of prey and common ravens are the biggest threats to fledgling birds. They hide in pine trees and thick shrubs to avoid great horned owls. Also, the dome above the nest may act as protection from great horned owls and common ravens. (Buitron, 1983; Erpino, 1968; Reebs, 1987; Trost, 2009)
Groups of adult and young black-billed magpies work together to attack predators. This usually gets the predator to stop hunting them. This is mostly used for defense, but probably also teaches the young which predators are more dangerous and need a stronger alarm call. (Buitron, 1983; Erpino, 1968; Reebs, 1987; Trost, 2009)
Black-billed magpies build sturdy nests that can last for 4 years or more. Their nests are often reused by other birds. Owls and ducks build their own nests on top of black-billed magpie nests, or use the domed nest as a shelter during the winter. Black-billed magpies sometimes eat ticks from the bodies of large hoofed animals like mule deer and elk. (Erpino, 1968; Todd and Worley, 1967; Trost, 2009)
Fly maggots and wood ticks are parasites to black-billed magpies because they feed on blood from very young ones. Black-billed magpies get lots of kinds of parasites in their intestines like roundworms, tapeworms, and flukes. They probably get a lot of parasites because they eat a wide variety of things. (Erpino, 1968; Todd and Worley, 1967; Trost, 2009)
Black-billed magpies cause some damage to fruit and nuts grown by humans, especially if there isn't much other food available and they are in large groups. The eat eggs and young chickens grown by farmers. They also eat insects that live on animal dung as well as dead or dying animals. They also pick insects out of open wounds on the back of farm animals, which can cause infection and death. Other times they eat the eyes of newborn animals. Because of these effects, farmers try to catch or frighten them using various methods. (Hall, 1994)
Black-billed magpies eat animals that are crop pests like grasshoppers, cutworm larvae, and wireworms larvae. When lots of their natural foods are available, they don't eat food crops or animals that humans raise. (Hall, 1994)
Black-billed magpies were treated as pests in the first half of the 1900s, because of their impact on farmed food and animals raised by humans. In some places, farmers still try to control how many there are, but they are still common in the places where they live. (Trost, 2009)
Black-billed magpies of North America used to be called a subspecies of common magpies. Then, genetic evidence showed that they were more related to yellow-bellied magpies, which live in California. The numbers of those birds was reduced dramatically since they started getting infected with West Nile virus in 2004. Because they are closely related, West Nile virus might become a problem for black-billed magpies in the future. (Birkhead, 1991; Lee, et al., 2003)
Steve Olson (author), University of Alberta, Augustana Campus, Doris Audet (editor), University of Alberta, Augustana Campus, Tanya Dewey (editor), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.
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