This is the Taiwan Blue Magpie (Urocissa caerulea), Taiwan´s National Bird.
"In the 2007 National Bird Voting Campaign held by the Taiwan International Birding Association, there were over 1 million votes cast from 53 countries. The Taiwan Blue Magpie defeated the Mikado Pheasant and was chosen as Taiwan's national bird, though it has yet to be formally accepted."
The Magpie postcard came (flying) :) with a Steere's Liocichla.The Steere's Liocichla (Liocichla steerii) is a species of bird in the Leiothrichidae family. It is endemic to Taiwan.
Now, my personal bad joke:
This proves that birds of different flock do fly together!
At least in letters!!!