"Birds on the other hand are now possibly THE major cause of crashes for large aircraft"
This document says you are very, very wrong.
For the "no feelthy PDFs" set, the last paragraph on page 7 includes:
"Interestingly, with all the recent attention and concern given to bird strikes in the United States, of the 700 commercial passenger fatality accidents worldwide in the 1990 through 2006 period, only six, less than one percent, were due to animal strikes."
Pilot error (40%) and equipment failure (23%) comprised the bulk of the fatal accidents covered in the paper.