A birdstrike is a high-speed impact between an aircraft and a bird or some other animal.
This is usually caused by the rotor hitting debris or a birdstrike.
the engine is having high pressure inside the combustion chamber.the flow has to move trough nozzle.incase the pressure is very high at nozzle compared to the intake pressure the flow moves forward.then the compressors shape changed it is not enough to compress the intake air.it is compressor stall