Birds Incorporate Human Materials Into Nests for Protection and Support

Magpies and crows in Europe are using anti-bird spikes collected from buildings to build nests.
A Dutch study found magpies utilizing the spikes to ward off other birds.
An unfinished crow's nest contained 336 spikes, suggesting they forcibly removed them.
Magpies use the spikes to improve nest defense against aerial attacks.
bird species use human-made materials in nests, but these can also harm birds.