There are many, many Common Buzzards (Buteo buteo) in Kephalonia - by far the most common raptor you'll see on the island, but there is also a small but healthy population of Long-Legged Buzzards (Buteo rufinus) also.
Long-Legged Buzzards are most numerous in Turkey and parts of the Balkans (although they are FAR from common), and they seem to enjoy a habitat of semi-desert, although they are found in wooded mountains and cliffs. In common with most Buzzards, they'll eat pretty-well anything, although in semi-desert areas, reptiles provide a large proportion of their diet. They'll search for food from high in the air, or potter about the ground in their 'pyjama bottoms', looking for lizards etc...
You'll need superhuman eyesight to note the longer legs of this Buzzard, but you may just notice its pale head (and chest often), its more eagle-like appearance, and the fact that unlike its common cousin, the Long-Legged Buzzard is seldom heard, although if you do hear it, you may note a shriller, higher-pitched shorter "mew".
We are pretty sure that as we left Myrtos Beach for the final time (after getting engaged!), one Long-Legged Buzzard flew over the car, and we also saw one from our appartment balcony.