They were obviously inexperienced birds.. fat ones at that. Maybe it was their first Migration IOE.

Spoke with a friend of mine who is close to the investigation and he opined that some of the birds were in excess of 10lbs. Also, the airplane took LOTS of hits.. apparently the birds were practicing close formation. I can't remember where I saw the photo but there was a large dent just below the F/Os window indicating a rather large strike. Also, strikes along both wings.