There are over 200 million of these birds, and they are one of the most numerous species on the entire continent... and they are all descended from a hundred or so birds brought here in 1890 by a man named Eugene Schieffelin. You see, Schieffelin felt that North America should have all of the birds that are found in the works of Shakespeare. Thanks Henry IV, Part I, and bravo Mr. Schieffelin. Within 75 years they covering the continent, though their genetic diversity is quite low.
Starlings compete for nests with native species, (though luckily most have been holding their own against them) destroy crops, and are carrier of a handful of harmful diseases that affect humans, including Histoplasmosis. Starlings also like to roost near Airports, which has caused numerous problems, including a crash that resulted in the death of 62 people.