A team of Dutch researchers has discovered that magpies (喜鹊) are using metal spikes (things with sharp points) designed to keep them away from certain urban areas to make their own nests stronger and keep invaders at bay.

Scientists have known for a while that magpies are some of the most intelligent birds in the world, but even they were puzzled by their amazing ability to adapt to hostile urban environments, It's not unusual for birds to use human trash as tools and building materials for their nests, but seeing them use the very things we humans use against them was nothing short of puzzling for researchers at the Natural History Museum in Rotterdam and the Naturalis Biodiversity Center in Leiden, in the Netherlands.

"I didn't expect this. These anti bird spikes are meant to deter birds, they are supposed to scare them off, but on the contrary, the birds just use them." Kees Moeliker, the director of the Natural History Museum Rotterdam, told The Guardian.

One particularly impressive magpie nest was discovered in the courtyard of a hospital in Antwerp, Belgium. It was made up of around 1,500 anti-bird spikes, most of which seemed to be positioned with the sharp point outwards, as protection against invaders. After discovering it, researchers checked the roof and confirmed that around 50 meters of anti-bird spike strips had been ripped off the building, leaving only the glue used to fix them in place.

Birds have been known to take sharp objects, from point y branches to nails, screws, into their nests as protection, but the use of anti-bird spikes is kind of ironic, as they are the very things used to keep them away. To scientists like Hiemstra, this is a sort of "beautiful revenge".

A few years back, we wrote about rich people in the UK installing anti-bird spikes on trees to stop birds from pooping on their luxury cars, but I guess the birds had the last laugh...