Dutch researchers have found that some bird species are using 'anti-bird' spikes in their nests to maximise protection.
A Magpie nest made of anti-bird spikes in a tree in Antwerp (Auke-Florian Hiemstra).
In a tree near a hospital in Antwerp, Belgium, a Magpie made a nest containing some 1,500 metal spikes. The spikes on the side of the building closest to the tree were gone, while those on the other side were still intact. This suggests that the birds have been ripping the spikes out, as opposed to collecting loose spikes.
The researchers have also seen magpie nests with defensive domes containing barbed wire and knitting needles.
"It sounds like a joke," said Auke-Florian Hiemstra at the Naturalis Biodiversity Center in the Netherlands. "But it's kind of heart-warming that these birds are actually outsmarting us and using anti-bird material for their own benefits."
The research is the first well-documented study that says birds appear to be positioning the sharp spikes outwards, maximising protection. Birds often use thorny branches as nest material, sometimes placing them as a roof to ward off predators and protect their young. In cities, however, there is a lack of prickly branches around, so it seems a few birds have turned to anti-bird spikes.
Hiemstra, A-F, Moeliker, C W, Gravendeel, B, & Schilthuizen, M. 2023. Birds nests made from anti-bird spikes. Deinsea: 21: 17-25