I know that bird strikes can bring down a plane but what about a helicopter. I know it’s not going to do the bird any good. Would it unbalance the rotors or damage one so bad the copter would have to land or crash? I know that there are a lot of variables but lets say a 4 or 5 lb. bird get a fowl (get it, a fowl) of a rotor blade.
Yes, they’re just as bad. While in Iraq our helicopter hit a bird but luckily it hit my flight engineer. If the bird gets into the engine the engine could lose power.
I hit two while flying Hueys. First on hit the mast and did no damage, second one broke my landing light. Definitely wouldn’t want to take one in the windscreen. I think hitting the blade wouldn’t be good but also not catastrophic. I knew guys that thit tree branches and only nicked the blade. The prevailing thought when encountering birds was to continue your course and they would usually change direction.
Not a problem hitting a blade. You can cut down small trees with those things and they will survive. Hitting most of the rest of the helicopter is not generally as bad as a commercial airliner as helicopters do not go as fast, but designers have a habit of sticking all kinds of shit on the outside of helicopters and these could be damaged like rsat3acr said. The big danger is them being sucked into the engine like RandMcnally mentioned. A lot of helicopters have diverters on the engine intakes that prevent things like sand getting in. Not sure they would help with something like a bird though.
I’m always amazed that bird strikes even happen. I mean, birds managing to get run over by cars is dumb enough, and ones already in flight have considerably more warning and opportunity to “take evasive action”.
Aircraft do move quite a bit faster than most things we have experience with. At 450 MPH, a plane can close the gap between “too far away to be noticeable” and “right on top of you” very quickly.
Also, birds are dumb.
Hueys and Black Hawks have pretty stout blades. I wouldn’t want to hit so much as a twig in a Robinson or Hughes/Schweizer/Sikorsky 300. I’ve seen pictures of a delaminated R22 blade, and since the helicopter was intact I presume a successful emergency landing was made. Stilll…
OTOH, I don’t have to worry about a bird being sucked into the engine. 
I’m an ace and then some. Last one was a hawk. (You should see the other guy!)
A small helicopter like a Robbo or Schweizer flies around at about 70-90 knots. Closure is much slower. I remember I was making an approach to land one day, and there was a hawk ‘in the pattern’ ahead of me. I reckoned he was there first, so I moved over to the right. Not even flapping his wings, he turned his head to look at me; then he looked ahead and continued straight ahead on his way.
our engine intakes were covered unlike those on things such as a comercial jet. Yes we had a particle seperator(I think thats what they were called, got out in 1985 and my memory is reduced every year) for little things such as sand. I was flying at Ft. Bliss so we had lots of sand.
Our normal cruse speed was 90 kts not any where near that of a fast mover.
Back in the day we hit a few. Luckily they were small. Any bird strike on the rotors required a mandatory blade inspection. Iirc it wasn’t required to do a precautionary landing you just had to inspect during your next shutdown.