Birds Turn the Tables: Using 'Anti-Bird' Spikes to Fortify Nests

Birds, specifically magpies and crows, have been observed stealing anti-bird spikes installed on buildings and using them to build their nests. Researchers from Dutch natural history museums discovered this phenomenon in a hospital courtyard in Antwerp, where magpies had constructed a nest using around 1,500 stolen spikes. The behavior is seen as an "ultimate adaptation to life in the city," providing an urban alternative to thorny branches for nest protection. Similar nests have been found in the Netherlands, Belgium, and Scotland, and other sharp materials like barbed wire and knitting needles are also used by magpies for nest construction.