Cheeky Birds Use Anti-Bird Materials to Build Nests

Jul 19

Jul 19 Cheeky Birds Use Anti-Bird Materials to Build Nests

Urban architecture often uses bird-unfriendly materials – spiky wires and nails, e.g., on ledges, statues, and elsewhere – to discourage birds from nesting and pooping on human structures. It mostly works, but now some clever crows and magpies have been removing the anti-bird bits and are using them to build their nests.

Auke-Florian Hiemstra, a biologist at the Naturalis Biodiversity Center in the Netherlands, first happened upon a bird’s nest using so-called hostile architecture outside an Antwerp hospital in 2021. Near the top of a sugar maple, a Eurasian magpie had built a nest of thin metal rods that had been pinched from a nearby ledge.

“I couldn’t believe my eyes,” Hiemstra tells the New York Times. “These are birds making a nest with anti-bird spikes.”

Over the next couple years, Hiemstra and colleagues began spotting other nests, some built by magpies and others by crows, made of the anti-bird spikes. Their research is published in the journal Deinsea.

Magpies and crows are both corvids, notoriously intelligent birds, and the researchers found subtle differences between their respectives nests. The magpies tended to arrange the business ends of the spikes upward, presumably to protect against predators. Crows were more likely to point the spiky parts down, using the materials to firmly secure their structures in place.

Birds all over the world use discarded human trash – cloth rags, plastic, dental floss, whatever – to build their nests. These clever corvids have taken that technique to another level.

Hiemstra, for one, is thrilled. “They’re outsmarting us,” he gushed. “We’re trying to get rid of birds, the birds are collecting our metal spikes and actually making more birds in these nests. I think it’s just a brilliant comeback.”