Mute Swans all over again

Today's New York Times has an article by Thomas Kaplan wherein ignorance and sentimentalism trump science and the environment. The Noble, Gentle Swan Is Anything but, to Some makes a hero of Kathryn Burton, president of SaveOurSwans U.S.A., a nonprofit organization in East Lyme, Conn. The article says Mute Swans are "considered an invasive species — a label Ms. Burton contests," but Kaplan doesn't detail either her reasoning or what the basic definition of an invasive exotic species is. The article casts a lot of heat on the issue, but sheds little light.