A short weekend trip to Leprokaria (close to Litochoro and Katerini) can be very rewarding.
I managed to see Levant Sparrowhawk quite a few times (lot of birds are nesting in the area) and managed to take some close pics of Red-backed Shrike, Black-eared Wheatear.
Other interesting birds that nest in the surrounding area:
Lesser Kestrel, Common Buzzard, Peregrine Falcon (@Olympus Mt), Eleonorae's Falcon (@Olympus Mt.), Hoopoe, Common Whitethroat, Subalpine Warbler, Cirl Bunting