Early October is quite good for northren Greece.
You can start in Thessaloniki.
Not far from the airport are some spots for waders.
1,5 h drive to Kerkini lake or 2 h drive to Rhodopes.
The Rhodopes get very colorful middle of October.
In October you will see not so much small birds, but Flamingo, Pelicans, Raptor, Terns and many waders.
Driving on Northern Greece streets is very relaxed and much more relaxed in Rhodopes.
But if You have more time, than visit also Porto Lagos. Many waders and terns I saw there.
Also Axios Delta is recommended.
If You want expand your vacation trip, there are many other areas not so far like Olymp and Meteora.
I was last year 2,5 weeks in northern Greece.
http://www.birdwing.eu/
This book is very helpful
http://www.birdwing.eu/birdwing-books