Damien Farine

So these tags use a new incarnation of this technology called Bluetooth Low Energy.

They effectively send a signal out every couple of seconds and this signal is then picked up by other devices, almost any electrical device now that has Bluetooth capability.

They take the location of the device and then they send that to the cloud.

It's actually not just phones.

Firstly, it's smartwatches and anything that has a GPS on it.

But it's done sort of behind the scenes.

So it's all completely anonymous.

And it's all encrypted as well, the information.

So there's no real way of knowing who the phone was, what the phone was doing or anything like that.

The most common way that people do this now is they get these GPS tags and the tag itself records the location of the bird.

We face a whole bunch of different trade-offs when dealing with this kind of hardware because it's quite energy intensive.

So you have to have a big battery and that puts on a lot of weight.

So, you know, we have to either shrink the battery.

So one way we've been getting around that with solar panels, but then that increases the cost of the tags.

So some of these tags cost, you know, a thousand pounds or a thousand five hundred pounds or something per tag.

These tags themselves, they don't have any GPS on them.

They don't have almost any hardware, just this tiny little low-powered Bluetooth chip.

It allows us to basically farm out the whole processing energetic needs to the phones that are receiving the signal as opposed to having to do it specifically on the tag itself.

One very small battery now can last for two or even three years on a tag.

So this is really made possible by the fact that every phone has Bluetooth on it.