Starlings are a widespread group of passerine birds, familiar across much of the globe. These highly adaptable birds are known for their strong, direct flight and gregarious nature, often forming large, noisy flocks. Found in various habitats, from open country to urban areas, starlings have successfully established populations in diverse environments. Their biology and ecological interactions are notable.
Physical Traits and Global Distribution
Starlings are medium-sized birds. The common starling (Sturnus vulgaris) measures about 20 cm (8 inches) long, with a wingspan of 31 to 44 cm (12 to 17 inches) and weighs between 58 to 101 grams (2.0 to 3.6 ounces). Their plumage is typically a glossy black with a metallic sheen, often displaying iridescent purple or green hues. In winter, their feathers are distinctively speckled with white tips, which wear away by summer, revealing a darker, glossier appearance. The legs are pink, and the bill changes color seasonally, being black in winter and yellow in summer.
Starlings are native to Europe, Asia, Africa, northern Australia, and the tropical Pacific islands. The common starling has a native breeding range across temperate Europe and the Palearctic region to western Mongolia. Many species, especially the common starling, have been introduced to new regions globally, including North America, Hawaii, New Zealand, Argentina, and South Africa. For example, a small group of about 100 European starlings released in New York City in the late 19th century has grown into an estimated population of 93 million in North America, spanning from Alaska to Mexico.
Remarkable Behaviors
Starlings exhibit several behaviors, with murmurations being a striking example. These large, synchronized flocks, sometimes numbering in the hundreds of thousands, create aerial displays as they twist and turn. This coordinated movement serves as a defense mechanism against predators like hawks and falcons, making it difficult for them to target individual birds. Information moves quickly across the flock, allowing individuals to respond to threats detected by their neighbors.
Starlings are renowned for their vocal mimicry, imitating the calls of other bird species, human speech patterns, and various environmental sounds. They possess diverse vocalizations, including whistles and warbles, used for attracting mates and warning of dangers. Male starlings engage in courtship rituals, puffing out feathers and singing complex songs to attract females.
Starlings are omnivores, consuming insects, fruits, seeds, and human food scraps. They employ a technique called “open-bill probing” or “zirkeln,” where they insert their bill into crevices and forcefully open it to expose hidden prey, such as grubs. Starlings nest in cavities, often competing for sites like holes in trees, buildings, or rooftops.
Ecological Impact
The widespread distribution of starlings, particularly in regions where they are introduced species, has led to various ecological impacts. Starlings compete aggressively with native cavity-nesting birds, such as woodpeckers, bluebirds, and purple martins, for nesting sites. This competition can lead to displacement of native species, with starlings sometimes destroying other birds’ nests or pecking holes in their eggs.
Beyond nesting competition, large flocks of starlings can cause agricultural damage. They consume and damage fruit crops, including grapes, cherries, peaches, and olives, and can also dig up newly sown grains or eat planted seeds. Damage to agriculture in the United States from starlings has been estimated at approximately $800 million annually. Additionally, starlings can contaminate livestock feed and water sources with their droppings.
Starlings can also play a role in disease transmission. Their droppings may contain the fungus Histoplasma capsulatum, which causes histoplasmosis in humans. Starlings can be vectors for diseases affecting livestock, such as transmissible gastroenteritis (TGE) virus in swine and Shiga toxin-producing Escherichia coli (STEC) in cattle. While direct evidence linking starlings to widespread disease outbreaks can be complex, their close contact with humans and farm animals raises concerns about their potential role in pathogen spread.