Unless it was blatant pilot error on the ground, the ONLY explanation is a bird strike. What strikes me odd is that one would THINK the pilot would have realized a bird strike. Good thing that it didn't hit the windscreen..... 
Airliner windshields are designed to shrug off a bird strike, but the nose is generally covered by a composite structure that is transparent to radar, as the aircraft's radar antennas are located behind the "radome" in the nose. I'd say he either hit a bird, or overshot the marks during parking at the ramp, and hit the building (I've seen that happen, and it is really embarassing!).
doc
The nose was dented in though. If he struck the building, you'd think it would be flatter. I'm convinced it's a bird strike myself.
As for the windshield part, you'd think military aircraft would be better protected then civilian aircraft. And look at what that bald eagle did to that C-130 in those pictures I posted.
I agree that it was a bird strike as well....which reminds me of an interesting story......Part of ceritfications standards testing for airliners here in the US (and I assume for military aircraft as well) there is a pneumatic "cannon" that fires dead chicken carcasses at the windshields and other parts of aircraft to simulate bird strikes.......some years ago, the Europeans decided to adopt this manner of testing, and after their first attempt, the FAA received a panic call from the euroweenies that the "chicken" not only penetrated the windshield, but also the bulkhead behind the cockpit, and ended up embedded in the galley cabinets.......causing millions in damage to the prototype being tested.
After examining the test data from the European testing agency, the FAA's reply was simply.......
...."you first have to
thaw the chicken before use".......
doc
