I remember about a decade ago when I saw the first Eurasian Collared-Dove in my town, and I thought it was an escaped pet! Now they are already an accepted breeding species on the official Louisiana bird list and they have become a regular in my yard. I was just watching a chase a few minutes ago -- I assume a territory thing -- looked too fast and intense to be courtship.
There's a link here if you don't know what I'm talking about--
http://www.birdsource.org/features/eucdov/But even if you don't know what I'm talking about now...you will.
The conservation movement is a breeding ground of communists
and other subversives. We intend to clean them out,
even if it means rounding up every birdwatcher in the country.
--John Mitchell, US Attorney General 1969-72