Why birds decorate their nests with weird and unnatural objects

Birds may decorate nests with artificial objects and feathers to deter magpies and ravens from taking their eggs.

Many birds have been observed placing human-made objects in their nests, such as plastic, wires or even anti-bird spikes from buildings. Often, these things seem to have no role as insulation or structural support, and may make nests more conspicuous to predators.

Magne Husby at Nord University and Tore Slagsvold at the University of…