Hmm. Birdstrikes. These can be nasty. Very nasty indeed. When we design an aircraft, we take this into account and there are specific tests for the canopy and forward structures to ensure that most birdstrikes do not penetrate the fuselage. However, high-flying geese, vultures and other large birds still present a hazard.
About 10 years ago a BA (?) 747 flying from the Americas to the UK hit a canada goose at altitude (and high speed). It penetrated the windscreen and, although it missed the pilots, the resulting rapid decompression sucked the captain out through the resulting hole. The first officer (who had been strapped in at the time) managed to grab his legs but couldn't pull him back in again. The flight continued to the nearest airfield, with the first officer flying and the chief stewardess holding onto the captain's legs. He survived, but with hypothermia and windburn.
If you look at a military flying helmet, you will see that it has two visors. One is tinted and the other is clear. You always keep the clear visor down, specifically in case you have a bird strike. I have seen several helmets that have been hit by birds coming through the windscreen and they make an incredible mess. I saw one that hit a bird at about 650 kts. That was one very dead bird!
A couple of design/test anecdotes for you. I regret to say that I cannot confirm that these are not apocryphal, but they still make good after dinner anecdotes!
1. Back in the 80's in the UK, they tried (and failed) to develop an advanced train (called the Advanced Passenger Train (ATP), funnily enough) that could travel down the normal tracks at about 150mph. The bigwigs decided that it travelled fast enough to warrant being tested for bird strikes. So they borrowed the bird strike machine from Rolls Royce aero engines, and set up the test. In front of an audience of top railway brass, they fired the bird and it went straight through the front of the train and wrecked the first carriage. During the investigation as to why it failed the test, it was found that the primary cause was that they had used a chicken as the test bird, but it was still frozen at the time of the test! Frozen chicken at 250 mph... hmm.
2. Westland Helicopters were performing a bird strike test on the Super Lynx. They had set up the test rig and put in the bird when the whistle went for lunch. When they returned from lunch, they fired the machine. The resulting 'Splat' didn't sound normal, so they inspected the impact area. Funnily enough, the canopy was covered in blood and feathers and fur and other remains. One of the engineers pointed out that the last time they had seen a furry chicken was in a student's fridge. So they traced back and worked out that, while they were at lunch, one of the local cats had smelt the bird and was having a wonderful free lunch right up to the point when it was fired into a helicopter at 250 mph! I can't tell you if the Super Lynx is now certified not only for birdstrikes, but for cat strikes as well...
The definition of a 'Pessimist': an Optimist with experience...