Blackbilled Magpie

The black-billed magpie, also known as the American magpie, is a conspicuous member of the Corvidae family found across the western half of North America. Recognisable by its striking black-and-white plumage and iridescent blue-green wing and tail feathers, the species inhabits a wide range of open and semi-open environments. Once considered a subspecies of the Eurasian magpie, it is now recognised as a distinct species on the basis of genetic and behavioural differences. Its intelligence, adaptability, and long-standing relationship with humans have made it a familiar bird throughout its range.

Taxonomy and Systematics

The black-billed magpie was first formally described in 1823 by Joseph Sabine under the name Corvus hudsonius, reflecting early assumptions about its affinity to crows. For much of the nineteenth and twentieth centuries it was grouped with the Eurasian magpie as a subspecies (Pica pica hudsonia), due to superficial similarities in plumage and morphology. Later assessments identified notable differences in body size, tail and wing length, and vocalisations.
In 2000, mitochondrial DNA studies demonstrated a significant divergence between the North American and Eurasian populations, prompting the American Ornithologists’ Union to recognise Pica hudsonia as a separate species. This research also showed that the black-billed magpie is more closely related to the yellow-billed magpie (Pica nuttalli) endemic to California. The generic name Pica derives from Latin for “magpie”, while the specific epithet hudsonia commemorates the English explorer Henry Hudson.
The term “magpie” itself originates from Middle English, combining “pie” for the bird and “Mag”, a diminutive of Margaret, reflecting the species’ reputation for chattering. Fossil evidence indicates that ancestral North American magpies arrived via Beringia during the mid-Pliocene, around 3–4 million years ago. Subsequent geological and climatic changes, including the uplift of the Sierra Nevada and repeated glacial cycles, facilitated divergence between the Eurasian, black-billed, and yellow-billed lineages. Limited gene flow may have persisted between the latter two during interglacial periods.

Physical Description

The black-billed magpie is a medium-sized corvid with a total length that places it among the more striking birds of western North America. It displays a glossy black head, breast, and back, contrasted by white scapulars and belly. The wings and elongated tail shimmer with iridescent blue-green tones, especially in strong light. The tail feathers are layered, with the central pair typically longer than the others.
The species lacks pronounced sexual dimorphism, although males are generally 6–9% larger and up to 24% heavier than females. Adult birds possess uniformly black, slightly curved beaks and dark irises. Juveniles differ in appearance, exhibiting reduced iridescence, buff-tinged scapulars, shorter, rounded tails, and grey irises. Their pink mouth linings fade after the first year, when the post-juvenile moult produces mature plumage.
Distinguishing features include the longer tail and all-black bill, which separate it from the yellow-billed magpie. Although visually similar to the Eurasian magpie, the latter has a shorter tail, proportionally shorter wings, and diagnostic differences in vocalisations. Geographic separation further prevents confusion in the wild.

Vocalisations

Black-billed magpies produce a varied repertoire of calls, including purrs, coos, shrills, and squawks. The most characteristic is a harsh alarm chatter described as kak-a-kak-a-kak, sometimes preceded by a softer skah. This call differs markedly from that of the Eurasian magpie but closely resembles the yellow-billed species. The magpie’s vocal flexibility is notable, and at least one individual kept in captivity has been recorded imitating human speech.

Distribution and Habitat

This species occupies a wide swathe of western North America. Its northern extent includes coastal southern Alaska, the Yukon, and central British Columbia, while its range continues south through Alberta, Saskatchewan, Manitoba, and the Rocky Mountain states as far as New Mexico. It extends cautiously into the northern Great Plains, reaching Minnesota, Iowa, and occasionally Wisconsin and Michigan. Its eastern and southern limits are shaped largely by climatic intolerance to high humidity and heat.
The black-billed magpie is absent west of the Cascade Range and the Sierra Nevada, where the yellow-billed magpie replaces it. During the breeding season, it favours riparian corridors, woodland edges, and thickets. Its broader habitat preferences include meadows, farmlands, ranchlands, suburban neighbourhoods, and areas associated with human activity such as feedlots, grain storage facilities, and landfills.
Although generally resident, some populations undertake limited winter movements. These are believed to result from dispersal after breeding and a later return to familiar nesting sites.

Behaviour and Feeding Ecology

Highly opportunistic omnivores, black-billed magpies forage both on the ground and from perches. They consume insects, worms, small rodents, eggs, carrion, and plant material. Historically linked with bison herds, they now frequently perch on cattle to remove ticks and other parasites. Their scavenging behaviour extends to following wolves or other large predators to feed on remains of kills.
Ground foraging is common, with the birds walking or hopping while probing for beetles, grasshoppers, and other invertebrates. Their adaptable feeding strategies contribute to their success in human-modified landscapes.
Socially, magpies form long-term pair bonds, although studies have shown variation in divorce rates across populations. Some nesting areas form loose colonies when suitable nesting trees are limited or food resources are abundant. Only the immediate surroundings of the nest tree are defended, enabling relatively dense nesting clusters.

Breeding and Nesting

The breeding season begins early, with nest construction typically starting in February and extending later in northern regions. Both sexes participate in building large, domed nests from sticks, branches, rootlets, mud, and fur. The structure includes a twig-built hood or dome and a single side entrance. Nests are usually positioned near the tops of trees and take 40–50 days to complete. Their sturdy construction allows occasional reuse after repairs.
Clutches usually contain six to seven eggs. Incubation is undertaken solely by the female and begins once the entire clutch is laid, lasting 16–21 days. The nestling period spans three to four weeks, during which both parents provide food. Wild individuals typically live for six to seven years.

Relationships with Humans

The black-billed magpie features prominently in the cultural narratives of Plains Indigenous peoples, often depicted as a clever and resourceful companion species. Its boldness and adaptability have facilitated close, though at times contentious, relationships with human settlements.
During the early twentieth century the species was widely persecuted due to perceptions that it harmed game birds and livestock. This led to regional population declines. In modern times, however, the species has recovered and is listed as of least concern by the International Union for Conservation of Nature. Its conspicuous presence, intelligence, and striking plumage continue to make it a familiar part of the avifauna of western North America.