Word is most of the parrots came to Brownsville after the last freeze in the early 80's. The hollowed trunks of dead palm trees provided natural cover.
They spend a lot of time around the old Charles Stillman house. Stillman was a cronie of the late Richard King (King Ranch). They roam around town a lot without an obvious method to their madness. In a non-scientific study, my son says they usually hit St. Charles Street early, only to return a couple of hours later.
I've read that many of the yellow-crowned are former captives. Most or all of the red-crowned are wild.
tms