In Act 1, Scene 3 of the First Part of King Henry IV, Hotspur fumes:
"(The king) said he would not ransom Mortimer,/Forbade my tongue to speak of Mortimer,/But I will find him when he lies asleep,/And in his ear I'll holler 'Mortimer!'/Nay, I'll have a starling shall be taught to speak/Nothing but 'Mortimer,' and give it him/To keep his anger still in motion."
I would wager anything that Shakespeare had no idea that by writing one of these words he would be altering a continent's ecosystem. How could he know that one of his future fans, a pharmaceutical magnate named Eugene Schiffelin, would decide to pay tribute to the bard by introducing to North America all of the birds mentioned in Shakespeare. Shakespeare wrote the word "starling" only once, but in 1890 Schiffelin would import 60 European starlings and release them in Central Park where they would nest in the eaves of the American Museum of Natural History.
Those 60 birds (and another few dozen he released the following year) have multiplied. There are now over 200 million starlings in North America, from Alaska to Mexico, competing with other bird populations for food and nest space. When the indigenous birds who migrate south return to New York, the starlings, who share no migrational impulse, are there to cackle at the homeless birds' misfortune.
Schiffelin is also responsible for introducing the house sparrow (to Brooklyn, in 1851), another pest species now widespread across the continent. This bird appears in four of Shakespeare's plays.