A noisy, aggressive bird, the European starling has been introduced into almost every corner of the world, generally because of its good looks [source: Columbia]. In the U.S., this introduction took place in about 1890, when Shakespeare lovers released 100 European starlings into Central Park so that North America would be home to every bird mentioned in the Bard's plays. Now, more than 200 million European starlings call the continent home [source: OMAFRA].
In addition to their comely looks -- which include glossy black feathers sprinkled with iridescent green and purple flecks -- starlings are omnivores, and congregate in flocks of up to 1 million or more. That's not a typo. These massive hordes devastate agricultural lands, and especially love to eat grapes, olives, cherries and grains. The birds will even settle over a field when crops are just beginning to poke their heads above ground, plucking up the tender, young plants to feast on the seeds. Starlings also chase out local bird species as they compete for food and nesting grounds, and can harm livestock and poultry facilities by swooping in to gobble up the food in feed troughs, contaminating the livestock's food and water as they eat. Their sizeable flocks are also believed to have caused a number of deadly crashes by colliding with planes [source: WebEcoist, Columbia].
Some people defend European starlings, as they do eat a lot of insects -- which is why certain countries, such as New Zealand, introduced them to their homeland in the first place. But most feel the damage the birds do far outstrips the benefits of their bug-eating [source: Columbia].