Sharp design: crows and magpies steal anti-bird spikes to build armoured nests

Birds have never shied away from turning human rubbish into nesting materials, but even experts in the field raised an eyebrow at the latest handiwork to emerge from urban crows and magpies.

- Ian Sample

Nests recovered from trees in Rotterdam in the Netherlands and Antwerp in Belgium were found to be constructed almost entirely from strips of long metal spikes of the kind that are attached to buildings to deter birds from setting up home.

The discovery prompted researchers at the Natural History Museum Rotterdam and the Naturalis Biodiversity Center in Leiden to scour the internet for further examples, leading to the identification of two more anti-bird spike nests, in Enschede in the Netherlands and in Glasgow.

"I really thought I'd seen it all," said Kees Moeliker, the director of the Natural History Museum Rotterdam, who studied the crow's nest found during tree maintenance near the city's main railway station. "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 utilise them."