The European starling, Sturnus vulgaris, is a bird native to Europe, southwest Asia, and northern Africa. This species was intentionally introduced to North America in the late 19th century, with significant releases occurring in New York City’s Central Park in 1890 and 1891. Since its introduction, the European starling has proliferated across the continent, becoming one of the most widespread and abundant bird species, with current estimates ranging from 150 to 200 million individuals. Recognized globally as an invasive species, the starling is listed among the “World’s Worst” invaders due to its extensive impacts on ecosystems.
Impact on Native Wildlife
European starlings directly affect native bird populations through intense competition for nesting cavities. These aggressive birds often usurp prime nesting sites from indigenous cavity-nesting species. Their aggressive nature extends to displacing native birds from feeding grounds and even involves behaviors like pecking holes in the eggs of other birds to eliminate reproductive competition. This fierce competition for limited resources can lead to declines in the populations of cavity-nesting native birds.
The starlings’ voracious appetites and tendency to gather in large flocks also create competition for food resources. They consume a wide variety of plant and animal matter, which can reduce the availability of food for native wildlife. This dual pressure of habitat and food competition contributes to the ecological challenges faced by native avian species in areas where starlings are prevalent.
Agricultural and Economic Effects
European starlings inflict substantial economic damage, particularly within the agricultural sector. They are known to devastate various fruit crops. For instance, a 2012 survey indicated that bird damage to sweet cherries ranged from 3 to 25 percent, while grape damage was between 4 and 10 percent, contributing to an estimated $189 million in total fruit crop losses. They also consume grains like corn and winter wheat, though this damage is generally considered less severe.
Beyond direct crop consumption, large flocks of starlings contaminate livestock feed and water sources with their droppings, leading to significant financial losses for farmers. Starlings are also implicated in transmitting diseases to livestock. The estimated annual agricultural damage caused by starlings in the United States was approximately $800 million as of 2000.
Public Health and Nuisance
Large populations of European starlings pose several public health risks and create significant nuisances. Their droppings can transmit various diseases to humans. These pathogens can survive in fecal deposits for extended periods, facilitating transmission through ingestion or direct contact.
The accumulation of starling droppings also causes considerable property damage. The uric acid in their feces is corrosive, eroding and staining paint, plastic, stone, metal, and masonry on buildings and vehicles. Large roosts generate significant noise pollution, which can be disruptive in urban and suburban areas. Nests built in vents and ductwork can create fire hazards and indoor air quality problems. Flocks of starlings near airports present a severe aviation hazard, increasing the risk of bird strikes with aircraft.
Broader Ecosystem Changes
European starlings contribute to more systemic ecological alterations beyond direct competition and agricultural impacts. Their omnivorous diet includes a wide range of insects, and while they consume agricultural pests, their overall effect on insect populations is complex and not fully quantified. Starlings play a role in seed dispersal by consuming various fruits and subsequently expelling viable seeds through regurgitation or droppings.
This seed dispersal can have both positive and negative consequences, as starlings are known to spread seeds of invasive plant species, which can disrupt native plant communities. The presence of large starling roosts can lead to localized nutrient loading due to concentrated fecal deposits. This influx of nutrients can alter soil chemistry and affect water quality in the immediate vicinity. Starlings’ high adaptability allows them to thrive in diverse human-altered landscapes, influencing plant distribution and overall habitat characteristics.