I saw four types. There was a long legged buzzard which was being mobbed by two common raven who clearly didn't want it around.
long legged buzzard at Old Marj
The bird I sighted most during the day was a female marsh harrier (see below).
marsh harrier at Old Marj
The biggest bird of prey I saw was a common buzzard. There are two things you should know. Common buzzard is not common in Libya despite its name though I suspect it is not as rare as many have believed. Second, it really was the biggest bird of prey I saw! Long legged buzzard in Europe is larger than common buzzard but the north African sub species of long legged buzzard (cirtensis) is actually smaller than a common buzzard.
Finally the other bird of prey I saw was kestrel.