That flock once lived in the Telegraph Hill area, but was chased out by the current flock. It flies a territory approximately four miles long that extends from the edge of the financial district to the eastern and southern rims of the Presidio. In the summer they extend their territory toward Noe Valley. The Canary wings can often be seen in the Noe Valley area as well. I haven't been seeing them as much as I used to.
Parrots are incapable of migrating.
They must remain in whatever territory they find themselves. This is why it seems that there are not as many of them at that time of year. They roost in a small park at Front and Jackson. This park is often mistakenly called Jackson Square or MacArthur Park. Its real name is Walton Square.