I have an EVGA P2 Supernova 1200 watt power supply and it started to make this chirping sound. Very similar to a small bird, and the sound was not loud, but still noticeable. It was definitely coming from the fan of the power supply. It did not do it constantly but on and off through out the day. I shut the pc down for the night and the next day I blew a lot of compressed air into it even though it was not dusty at all, but it did it even fainter after that. I blew more air into it while it was running and has not done it since. I was wondering what could have caused this or if it is something to be concerned about. It sounded exactly like this but maybe not quite as frequent. I wasn't doing anything taxing on my computer at the time, was just on Steam and browsing the internet.
https://www.youtube.com/watch?v=UPU9ENJQSU8
https://www.youtube.com/watch?v=UPU9ENJQSU8