Acoustic recorder set-up to capture birdsong

Manaaki Whenua – Landcare Research ecosystems and conservation researcher Neil Fitzgerald introduces us to the components of an acoustic recording device and how he sets it up to record birdsong.

Questions for discussion:

• Why might Neil set the acoustic recording device to only record at 8:00 pm?

• Why is it important to hang the acoustic recording device away from leaves and branches?

• Where would you hang the device to capture birdsong that you’d like to record?

Transcript

Neil Fitzgerald

Kia ora, ko Neil tōku ingoa kei Manaaki Whenua ahau, e mahi ana. My name is Neil and I work for Manaaki Whenua – Landcare Research based in Hamilton. 

One of the ways we survey for birds is to use electronic recording devices that look like this. These particular ones are designed by the Department of Conservation here in New Zealand. They used to be green, now they’re black, but they do the same job. 

There’s not a lot to these – basically just a microphone, some batteries, memory card and some electronics and firmware to make it all work. What we do is we put them out in the field – programs come on at a certain time of the day and then to turn off again after a certain amount of time – and then they repeat that every day until we come back and collect them. When we go back after a few days or weeks or however long, we can take out the memory card, download it to the sound files to a computer, and we can have a look at them and listen to them there or we can use software to scan through them automatically and find the birds that we’re interested in. 

On the inside, it’s got our batteries, memory card and some basic programming – the time and the date, and you can have two protocols, which is just when we want the recorder to come on and what we want it to do. So in this case, we can have it set to high, which will record all the sound frequencies that people can hear. Low just records the lower frequencies, which is good for things like kiwi with low-frequency calls because it saves space on the memory card. We could also use it to record bat calls. And this just tells it when to come on – start time 8 o’clock at night, in this case, and it would go for half an hour. And it would just repeat that every day turning on at 8 o’clock and recording for half an hour and then going back to sleep until the next day. Repeat that every day until either the memory card is full or the batteries are flat. You could have a second protocol or time of the day that we want it to come on and do something else. And that’s all there is to it, so we just close it up and take it outside.

We’re outside. Got our sound recorder, it’s raining a little bit – hope you can still hear me OK. These things don’t like getting wet on the inside. Electronics and water don’t go together very well, so it’s a good thing we’ve already programmed it, put in the batteries and put in the memory card inside. So all we’ve got to do now is find somewhere to hang it up. And that’s real easy. All I’m looking for is somewhere where it can hang without getting blown against anything or branches or leaves blowing against it because that makes a lot of noise in the recording. 

So, to hang it up, all we’ve got to do is get our twist tie, the sort of thing you might find in the garden centre, but any old bit of soft wire or cable tie will do, and then we just hang it up like that. And because it’s already programmed and everything, that’ll start recording when it’s programmed to come on, and we’ll keep doing that until we come back and collect it. 

I usually just hang them like this sort of at head height or something so it’s easy to get to. If you’ve got tutū fingers around, you might want to go and put it a bit further, bit more hidden behind some trees or something or a bit higher up or something like that. Some of the older recorders, they look very similar to this but they don’t have a thing on the top to hang them by, so you might see those attached to the side of a tree with a little metal bracket. But it’s exactly the same sort of thing, it’s just a different way of putting them up. So yes, so we just come back now in a few days or weeks or months and see what we’ve recorded.

AcknowledgementsNeil Fitzgerald
Manaaki Whenua – Landcare Research