Originally Posted by
ShyTorque
A big enough bird has enough mass to bring down almost any helicopter. Some will recall the USAF Pave Hawk tragically brought down after hitting geese in Norfolk, U.K. in Jan 2014, with the loss of its four crew.
Yes, the certification standard (CS or FAR 29.631) states a 1kg bird (at Vh), so anything above that and all bets are off.