This is bird note.

Tracking birds can be tricky, even with GPS technology.

Around 70% of bird species are just too small to carry a GPS battery.

But recently, Australian scientists developed GPS tractors that look like little backpacks

and weighed less than a gram.

They could charge wirelessly while the birds visited a feeding station, and could be quickly

released with a magnet when the study was over.

This would be less of a disturbance for the birds.

But there were some unforeseen complications.

The researchers fastened their tractors on five wild Australian magpies.

Almost immediately, one magpie tried to escape from the backpack.

Another magpie flew over to help.

He managed to pick exactly at the tracker's one millimeter weak spot, which was built

in so the magnetic release could work.

It only took 10 minutes for the birds to find it.

Soon, all of the magpies were tracker free.

The bright side was an unexpected discovery.

The magpies showed evidence of altruism by helping others without any benefit to themselves.

A rare behavior among birds.

Scientists are looking for a less intelligent and less social species to try the state of

the art trackers on next.

Lizards are possible candidates.

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