Inconclusive sighting

I wonder if Michael Pennay can check this one?

Hi, to identify could you please give some more information about this recording? What was it recorded on? I can hear audible chirps but need to know if the recording has been frequency divided?

It was recorded on an iPhone. We went and did the recording in response to the comments on the related sighting listed above. Same location, same bats (in theory). Cheers, Sandra

Ok thanks. Chalinolobus gouldii call around 30 kHz so without an ultrasonic microphone or processing it's about 10kHz above out peak hearing range so we can't hear them. The white striped mastiff bat makes audible calls around 12kHz that young people can hear. The audible pips on your recording sound lower than 12kHz, it's possible the iPhone has distorted the sound to lower it's pitch, but based on recordings I'd be reluctant to ID them as any bat. To me it really sounds like the alarm 'pip' call of Australasian Grebe , were you near a dam? Could you see the bats as you were recording or was it dark?

We actually used our phones to track the bats as they were flying past us, as we could hear the sounds get louder as they flew past. It was at dusk at the dam and we stayed until it was just getting dark. What a shame but it makes sense that the iPhone might downsample. I did convert this audio from a .mov file, so who knows what happened in the conversion. Or perhaps the iPhone picked up the audio of grebes and not the bats. What sort of equipment would we need to record bats in the future? I am happy to leave this sighting here as inconclusive or remove it.

To record the bats you need an ultrasonic bat detector. I have one I'm happy to lend to you if you want to try. Send me a message and we can arrange.