Crows and Magpies Using Anti-Bird Spikes To Build Nests, Researchers Find

Birds have never shied away from turning human rubbish into nesting materials, but even experts in the field have raised an eyebrow at the latest handiwork to emerge from urban crows and magpies. From a report: 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 that are often attached to buildings to deter birds from setting up home on the structures. The discovery prompted researchers at the Natural History Museum in 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: one in Enschede in the Netherlands and another 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." While the Rotterdam nest was made by crows, the other three were built by magpies, which construct large dome-like nests. The crows used the anti-bird spikes as a sturdy construction material, but the magpies may have appreciated their intended use: they placed most of the spikes on the nest's roof where they could deter predators, including other birds and weasels. [...] It is not the first time birds have been found to incorporate urban materials into their nests. In 1933, a South African museum reported a crow's nest fashioned from hard-drawn copper, galvanised iron and barbed wire. Nails, screws and even drug users' syringes have all found their way into birds' nests.

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