‘It’s Like a Joke, Really,’ Crows and Magpies Steal Anti-Bird Spikes to Make Their Nests

Crows typically make nests with items like branches and twigs, but new research finds they’re using something else to make them, something scientists say shows how clever they are.

Researchers from Naturalis Biodiversity Center and the Natural History Museum Rotterdam recently shared the findings on some “crazy” crow and magpie nests they’ve collected. The nests in question were made from anti-bird spikes, a widely used deterrent to discourage nest building.

Auke-Florian Hiemstra, study co-author and biologist from Naturalis, says, “It’s like a joke, really. Even for me as a nest researcher, these are the craziest bird nests I’ve ever seen.”

The first nest they collected was built by magpies up high in a tree in a hospital courtyard. This mammoth, which is currently on display in the LiveScience room at Naturalis, had up to 1,500 of these spikes, which the magpies had pulled from the eaves. The researchers say the birds appeared to have chosen these materials to keep other birds at bay. This is something they do in nature, anyway, looking for sharp objects like thorny plants to keep their nest safer from intruders looking to eat the eggs.

It’s not just this set of magpies that has displayed this sort of behavior, though. Other magpie nests, which are further detailed by the researchers in Deinsea, have been found with anti-bird spikes, and not just in the Netherlands. Belgian and Scottish magpies have been up to the same thing. Crows in the Netherlands have, as well, though that’s the only country in which this species has been observed doing so. This resourcefulness is even impressive to the researchers.

Kees Moeliker, study co-author and director of the Natural History Museum Rotterdam, says, “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.”

This isn’t the only recent study chronicling the use of non-natural nest building materials. Other research has found that birds across the world are also using litter to make their nests.