The starlings you see across North America today descend from roughly 100 birds released into New York City’s Central Park in 1890. A wealthy socialite named Eugene Schieffelin brought them from Europe as part of an eccentric personal project: introducing every bird species mentioned in the works of William Shakespeare to the United States. From that single release and a follow-up the next year, starlings colonized the entire continent in just over 50 years.
Their Native Range
European starlings are native to a broad swath of the Old World stretching from Central Siberia in the east to the Azores islands in the west, and from Norway in the north down to the Mediterranean Sea and North Africa. They thrive in open grasslands, farmland, and urban areas, which helps explain why they adapted so quickly once they arrived in North America. The habitat wasn’t all that different from what they’d left behind.
The Shakespeare Connection
Schieffelin was a member of New York’s social elite and belonged to the American Acclimatization Society, a group interested in introducing European plants and animals to North America. His particular obsession was literary: he wanted every bird Shakespeare ever mentioned to live in the New World. The starling appears in a single line of “Henry IV, Part 1,” where the character Hotspur suggests using a trained starling to drive King Henry mad by repeating a name over and over. That brief mention was enough.
On March 6, 1890, Schieffelin released 60 European starlings in Central Park. The following year he released another 40. These weren’t the first attempts to establish starlings in North America. Earlier introductions had been tried in Ohio, Quebec, Pennsylvania, Massachusetts, and Oregon, all apparently without lasting success. But the Central Park birds, numbering about 100 total across the two releases, found conditions they liked and began breeding.
How 100 Birds Became 200 Million
The speed of the starling’s spread is one of the more remarkable stories in North American ecology. From Central Park, they fanned out across the eastern United States within a few decades. By 1942, just 52 years after the first release, starlings had reached the West Coast. Today they inhabit all 50 U.S. states, most of Mexico, and parts of southern Canada. Population estimates commonly place the North American total at around 200 million birds.
Genetically, the math shouldn’t have worked this well. A founding population of roughly 180 individuals (combining both years and accounting for earlier small introductions) is tiny, and small founding groups typically suffer severe losses in genetic diversity that limit their ability to adapt. Yet genetic analysis shows North American starlings experienced only a moderate bottleneck. Their effective population size increased dramatically after introduction, meaning enough genetic variation survived to fuel rapid adaptation across a huge range of climates and habitats.
Not Just a North American Story
Schieffelin’s release is the most famous introduction, but starlings were deliberately brought to several other continents during the 19th and early 20th centuries. They were introduced to New Zealand, Australia, South Africa, and Argentina between 1856 and 1987. In New Zealand, genetic research has traced successful populations back to birds translocated from both the native European range and from Australia, showing that multiple introduction events contributed to the established population there. The pattern repeated around the world: people brought starlings intentionally, and starlings did what starlings do.
Impact on Native Birds
Starlings are cavity nesters, meaning they raise their young in holes in trees, cliffs, or buildings. The problem is that many native North American birds use the same type of nesting sites, and starlings compete for them aggressively. They’re slightly larger and more persistent than many native species, and they will evict birds that have already begun nesting. Sapsuckers, a group of woodpeckers, appear to have declined specifically because of starling competition for nest cavities. Other affected species include bluebirds, purple martins, and various woodpecker species that excavate their own holes only to lose them.
The competition is straightforward: there are a finite number of suitable cavities in any given area. When starlings take a large share of them, native birds either fail to breed that season or are pushed into less ideal locations. Conservation efforts for cavity nesters now often include specially designed nest boxes with entrance holes sized to exclude starlings.
Agricultural and Economic Costs
Beyond their effects on wildlife, starlings cause significant damage to agriculture. They feed in large flocks on fruit crops, grain fields, and livestock feed. One widely cited estimate puts annual agricultural damage in the United States at $800 million. Starlings also create problems at airports, where large flocks pose a serious bird-strike risk, and in cities, where winter roosts of hundreds of thousands of birds concentrate droppings that can harbor fungal spores harmful to human health.
Their roosting behavior is part of what makes them so visible. Outside the breeding season, starlings gather in enormous communal roosts that can number in the hundreds of thousands. These flocks create the swirling aerial displays known as murmurations, which are visually spectacular but less welcome when they settle on buildings, bridges, or agricultural operations.
Why They Succeeded
Several traits made starlings ideal invaders. They eat almost anything: insects, fruit, seeds, garbage, livestock feed. They breed quickly, producing one or two clutches per year with four to six eggs each. They tolerate a wide range of climates, from the heat of the southern U.S. to Canadian winters. And they’re comfortable around people, thriving in the suburban and agricultural landscapes that dominate much of the continent.
Their beaks have even changed since arriving. Research published in Scientific Reports documented measurable beak evolution in North American starlings since their introduction, suggesting they’re still actively adapting to local conditions across the continent. What started as a quirky Victorian hobby project became one of the most successful biological invasions in recorded history, all traceable to a man, a playwright, and a single line about a talking bird.