If you look around in cities, you can see anti-bird spikes on many buildings. The sharp metal spikes are placed to scare away birds, and to prevent them from building nests. But birds are not so easily scared away, it now appears. Researchers from two Dutch natural history museums collected nests of a carrion crow and a Eurasian magpie that were largely built with material that should have deterred birds: bird nests made of anti-bird spikes. “It’s like a joke, really” says biologist Auke-Florian Hiemstra of Naturalis: “Even for me as a nest researcher, these are the craziest bird nests I’ve ever seen.”

The adaptability and creativity of urban birds seem to know no bounds. Researchers from Naturalis Biodiversity Center and the Natural History Museum Rotterdam describe these spiky structures in the scientific journal Deinsea. “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,” said Kees Moeliker, director of the Natural History Museum Rotterdam and co-author of the scientific publication.

1500 metal spikes
It started with the discovery of