Around the world, anti-bird spikes protect statues and balconies from unwanted birds, but now the birds are getting their own back.

According to Dutch researchers, some birds use spikes to keep pests away around their nests in the same way that humans do.

Auke-Florian Hiemstra, a biologist, says the creature is remarkably adaptable.

It’s like a bunker for birds. They’re incredible fortresses.

Birds around the world use everything from barbed wire to knitting needles in their nests, including human-made objects.

It is the first well-documented study to show that birds appear to be positioning sharp spikes outwards, maximising protection.

In Antwerp, Belgium, Mr Hiemstra discovered an enormous magpie nest containing some 1,500 spikes in a hospital’s courtyard.

Initially, Mr Hiemstra said, he just stared at the nest – a strange, beautiful, bizarre nest.

Spikes pointed outwards, creating the nest’s perfect armour.

About 50m (164 ft) of anti-bird spike strips had been ripped off the hospital roof, leaving only glue trails behind.

There is a nest that has not yet been completed in the Rotterdam museum, and a nest that has been completed is in the Naturalis Biodiversity Center’s collection.

The nest architecture indicates the birds use the spikes as protection, but Mr Hiemstra says many more need to be discovered to prove his theory.

“They’re making a roof with thorny material for protection, so they aren’t just building a roof,” he says. “They are creating a roof with thorny material.”.

Mr Hiemstra says birds in built-up areas use thorny branches as protection for their nests because humans dislike these kinds of bushes and trees.

It demonstrates a remarkable adaptability to their environment, he says, as well as a determination to protect their nests, since the glue used to attach the spikes to buildings is strong and difficult to remove.

The cheeky cockatoo ripped away spikes on a building near Sydney in Australia, or the Melbourne Parkdale Pigeon went viral for building its nest right on top.

While humans may find this an annoyance, Hiemstra sees it as a “beautiful revenge”.

The material that we made to keep them away is being used to build a nest to make more birds.”