One autumn a few years ago I was climbing out of Thessaloniki (LGTS) at night when we hit a very large bird at 8000ft. It made a hell of a noise and initially gave us quite a shock! The windscreen appeared badly damaged although investigation showed that only the outer layer was cracked. Lots of grey feathers were attached to the wipers etc.
Later, I did some research and found that further north was an area of wetlands popular with a type of grey stork which migrates south to the Nile valley in winter; it was possibly one of these that we struck.