[Aerkuld]

I will say that we have just got through ceceda season down here and they are amazingly loud, easily loud enough to compare with that recording. The ones we have down here do build the noise up slowly, getting progressively louder and then fading off again. The call lasts several seconds but is a continous tone. I don't know if all species make the same call though. We also get all kinds of odd frogs which make similar noises, some of them sound more like a dogs yapping bark than a frog, but I would have thought that it's to cool up there at night for frogs. I can see why you say you thought it was a bird, it does sound a bit sqwauky. I would guess that it is some kind of insect, but I don't know how you go about finding out. Please keep us posted though.