You may be right, I chose "kaverit" because it can also be translated as "chaps", "dudes" or "fellas".
To my ear the best would sound to say "Rauha kanssanne, ulkomailla asuvat" but then the "birds" has no meaning in Finnish. Or then again, also "Rauha kanssanne, expatriaattitoverit." (or "...ulkomailla asuvat toverit", then it means that the writer is an expatriate himself and he is sending greetings to his expatriate fellows. Word "toverit" sounds a bit 60's (comrades) but is still used in certain contexts.
There are more varieties but I would need more information, for example, are we after the people who work as an expatriate or people who live abroad?
Thank you Juha!
No problem with your translation. I was hoping for some comments from turkish and/or english speakers to get the additional information - which, by the way, would be very useful to add in comments/remarks when submitting something for translation.