The birds fight BACK! Crows and magpies are using ANTI-bird spikes to build nests in ‘ultimate revenge’ against humans, scientist finds

Roof spikes have long been used by humans to keep birds at bay.

But it seems that crows and magpies aren’t so scared at all, having stolen countless sharp metal pieces to build their own fortified nests.

Experts at the Netherlands’ Naturalis Biodiversity Centre and the Natural History Museum of Rotterdam made the surprising discovery that birds make use of roof spikes to scare off predators.

Their research unexpectedly took off at a hospital courtyard in Antwerp, Belgium, where onlookers spotted a bird’s nest made up of 1,500 metal spikes.

It remains unclear how the birds get hold of the spikes without getting hurt, although MailOnline has contacted the researchers for further information.

One magpie had stolen 1,500 pins to protects their nests from lurking predators in a hospital courtyard in Antwerp, Belgium (pictured)

‘An impregnable fortress,’ Auke-Florian Hiemstra of Naturalis said. ‘Because the magpies appear to be using the pins exactly the same way we do: to keep other birds away from their nest.’

This Eurasian magpie’s nest was by no means the only example of this, with others already seen in Glasgow and Enschede in the Netherlands.

Carrion crows also exhibited similar behaviours near Rotterdam’s Central Station, placing an array of spiky objects in a weeping willow tree.

While crows were seen to use these sharp objects as a nesting material, magpies appeared to place spikes in a way that overarched their ‘dome’ nests.

This indicates that magpies primarily use spikes for the functional purpose of scaring off weasels and other birds.

Barbed wire and even knitting needles were among objects used by magpies too, as a way of protecting their nest roofs.

Even condoms and fireworks are frequently encountered by Mr Hiemstra, alongside cocaine wraps, sunglasses and windshield wipers.

‘It’s like a joke, really,’ Mr Hiemstra continued. ‘Even for me as a nest researcher, these are the craziest bird nests I’ve ever seen.’

Auke-Florian Hiemstra (pictured) said: ‘The magpies appear to be using the pins exactly the same way we do: to keep other birds away from their nest’

The Antwerp nest close up: A sneaky magpie had stolen as much as 150ft worth of anti-bird pins from nearby roofs to protect its eggs and babies from being snatched

Even condoms and fireworks are frequently encountered by Mr Hiemstra in the nests of magpies, alongside cocaine wraps, sunglasses and windshield wipers

Kees Moeliker, director of the museum, added: ‘Just when you think you’ve seen it all after half a century of studying natural history, these inventive crows and magpies really surprise me again.’

Antwerp’s magpie nest is now on display at the Live Science room of Naturalis in Leiden.

While birds’ lack of fear towards spikes is not a new concept, experts claim theirs is the first scientific publication to put this into words.

This also comes just days after a group of European scientists found that 176 bird species were using human-made materials to build nests.

This study, led by the University of Warsaw, saw that litter-collecting behaviour was particularly widespread among gulls, ducks and many birds of prey in all continents but Antarctica.

‘Many birds, including birds of prey, gulls and pigeons, are urban-adapted and breed successfully in cityscapes where human-made materials are readily available,’ the team wrote in The Conversation.

‘The extent to which birds adapt to polluted environments remains underappreciated because a study like ours is only as good as the available data.’