Not every bird seen across the Americas belongs there. Some species have been introduced from other continents, either by accident or through human activity, and are now spreading into new territories.
These invasive birds can compete with native species for food, nesting sites, and habitat, sometimes causing serious ecological disruptions.
This article is for general knowledge only and is based on information from online sources. Ecological effects can vary by region.
1. European Starling
Released in New York’s Central Park in 1890 by Shakespeare enthusiasts, these iridescent troublemakers now number over 200 million across North America.
Starlings form massive, swirling flocks that devour crops and steal nesting cavities from native woodpeckers and bluebirds. Their aggressive nature allows them to outcompete local birds for resources.
Farmers consider them serious agricultural pests, as large flocks can destroy fruit crops and contaminate livestock feed with their droppings.
2. House Sparrow
Those chirpy little birds hopping around urban sidewalks aren’t native to the Americas. House sparrows arrived from Europe in the 1850s and spread with astonishing speed across both continents.
Male house sparrows sport distinctive gray caps and black bibs, aggressively defending territory year-round. They’ve adapted perfectly to human environments, nesting in building crevices and feeding on our scraps.
Though their populations have declined somewhat since mid-century peaks, these birds remain abundant urban dwellers that outcompete native cavity-nesters.
3. Rock Pigeon
The familiar cooing pigeons that gather in city squares trace their ancestry to European birds brought by colonists in the 1600s. These rock cliff dwellers found perfect substitutes in building ledges and bridges.
Rock pigeons produce multiple broods yearly, explaining their ubiquitous presence from Mexico City to Montreal. Their adaptability to urban environments is remarkable, they can digest almost anything, from discarded pizza to birdseed.
While less aggressive toward native species than other invasives, their droppings damage buildings and potentially spread disease.
4. Eurasian Collared-Dove
A pet shop burglary in the Bahamas in the 1970s accidentally launched one of the most rapid bird invasions ever recorded. Escaped collared-doves reached Florida by the 1980s and now inhabit most of North America.
These pale, sandy-colored doves with distinctive black neck rings reproduce quickly in suburban areas. Unlike many invasive species, they don’t seem to aggressively displace native mourning doves.
Their expansion continues northward into Canada, where warming temperatures increasingly support their survival in southern provinces.
5. Mute Swan
Majestic but menacing, mute swans arrived in North America in the late 1800s as ornamental additions to wealthy estates. These enormous white birds with orange bills and graceful curved necks escaped captivity and established wild populations.
Don’t let their beauty fool you. Mute swans are territorial bullies that attack native waterfowl, sometimes drowning smaller birds. One adult consumes up to 4 kg of aquatic vegetation daily, destroying habitat needed by native species.
Particularly problematic in the Great Lakes region, these swans threaten the recovery of native trumpeter swans.
6. Monk Parakeet
Bright green with gray chest and forehead, monk parakeets bring tropical flair to unlikely northern cities. Escaped pets established breeding colonies in the 1960s across the southern United States.
Unlike most parrots, these social birds build massive communal stick nests on utility poles and towers. Their architectural projects cause power outages when built on electrical equipment, costing utilities millions in repairs.
Monk parakeets have proven surprisingly cold-hardy, establishing colonies as far north as Chicago and New York by nesting near warm transformers that help them survive winter.
7. Cattle Egret
A rare self-introduced species, cattle egrets flew across the Atlantic from Africa to South America in the late 1800s. From this natural bridgehead, they expanded northward, reaching Florida by 1940 and spreading throughout the Americas.
These white herons with yellow bills follow livestock and farm equipment, snatching insects disturbed by grazing animals. Their relationship with cattle is beneficial, they remove ticks and flies while getting easy meals.
Unlike many invasive birds, cattle egrets found an unoccupied ecological niche and generally coexist peacefully with native herons and egrets.
8. Ring-Necked Pheasant
That colorful rooster strutting through farm fields represents one of North America’s most successful game bird introductions. Native to Asia, ring-necked pheasants arrived in the 1880s when Oregon farmers released Chinese birds.
Males display iridescent green heads, red face wattles, and spectacular long tails, while females wear camouflage brown. Wildlife agencies continue releasing pheasants for hunters across the continent.
These ground-nesters sometimes lay eggs in the nests of native prairie chickens and other ground birds, potentially reducing reproductive success of already-struggling native species.
9. Grey Partridge
Nicknamed “Huns,” grey partridges journeyed from Eurasia to North American farmlands in the early 1900s as hunting quarry. Their mottled brown plumage provides perfect camouflage in agricultural landscapes from the Canadian Prairies to the northern United States.
These chunky ground-dwellers form tight-knit family groups called coveys that huddle together for warmth during harsh winters. They thrive in grain fields and shelterbelts where few native gamebirds existed before European-style farming.
Unlike many invasives, grey partridges filled a relatively empty niche in cultivated landscapes, minimizing competition with native species.
10. House Finch
Native to western North America but invasive in the East, house finches have a unique story. Pet shop owners illegally selling “Hollywood Finches” in New York released their stock in 1939 to avoid prosecution.
Males sport variable raspberry-red coloration on heads and chests, while females are streaked brown. From Long Island, they colonized the entire eastern seaboard within decades, eventually meeting their western cousins in the middle of the continent.
These cheerful songsters now frequent bird feeders continent-wide, potentially outcompeting the similar native purple finch in some areas.
11. Chukar Partridge
Bold black-and-white striping on the flanks makes chukar partridges unmistakable against the arid hillsides they call home. Native to Middle Eastern mountains, these game birds were released extensively across western North America starting in the 1890s.
Chukars favor steep, rocky terrain that mimics their ancestral habitat. Their distinctive “chuck-chuck-chukar” calls echo across canyons from California to British Columbia.
Interestingly, chukars have developed a taste for invasive cheatgrass seeds, potentially providing minor ecological benefits by consuming this problematic plant that native wildlife tends to avoid.
12. Eurasian Tree Sparrow
While its cousin the house sparrow conquered the continent, the Eurasian tree sparrow demonstrates that not all invasions succeed equally. Released in St. Louis in 1870, these sparrows with chestnut caps and black cheek spots remain largely confined to the St. Louis region.
From just 12 original birds, they’ve grown to perhaps 15,000, which is minuscule compared to house sparrow numbers. Their limited spread likely stems from competition with the larger, more aggressive house sparrow.
Birders often travel specifically to St. Louis to see this localized specialty, making it a peculiar attraction rather than an ecological problem.
13. Eurasian Skylark
Renowned for spectacular aerial singing displays, skylarks were introduced to Vancouver Island in 1903 by homesick British colonists. These brown-streaked ground-nesters once numbered around 1,000 birds in Victoria’s farm fields.
Male skylarks hover high above territories, delivering complex songs that inspired classical composers and poets. Unlike most invasive success stories, skylark populations have crashed to fewer than 100 birds, restricted to fields near Victoria International Airport.
Changing agricultural practices eliminated suitable nesting habitat, demonstrating that not all introduced species thrive in new environments, even with human assistance.
