Crows and Magpies Utilize Anti-Bird Spikes for Nest Building

Recent research uncovered a fascinating aspect of urban bird behavior, particularly in crows and magpies. These birds have showcased a remarkable ability to adapt to city environments by using unconventional materials for nest construction. The findings emerged from studies in Rotterdam, Netherlands, and Antwerp, Belgium.

Bird nests in these cities were found predominantly comprising strips of metal spikes designed to deter avian residents. These anti-bird spikes are usually installed on buildings to prevent birds from nesting in unwanted areas. This discovery prompted researchers from the Natural History Museum in Rotterdam and the Naturalis Biodiversity Center to investigate further. They discovered additional nests in Glasgow and Enschede that also featured these spikes.

Kees Moeliker, the director of the Natural History Museum Rotterdam, expressed genuine surprise at this finding. He emphasized, "I didn’t expect this," noting the irony of birds utilizing spikes intended to scare them away. Whereas the Rotterdam nest belonged to crows, the others were the work of magpies. The magpies strategically placed many spikes on their nest roofs, possibly using them as a defense against predators.

Auke-Florian Hiemstra, a biologist with the Naturalis Biodiversity Center, remarked on the nests' uniqueness, stating, "These are the craziest bird nests I’ve ever seen." Incorporating urban materials into nests is not a new behavior. Historical examples include a crow's nest from 1933 made of copper and barbed wire. Various urban materials, such as nails and syringes, have also appeared in bird nests.

Moeliker recalls collecting a unique pigeon nest over 25 years ago, built from chicken wire "in a place with nothing green." He initially thought this nest was the pinnacle of urban adaptation, until the recent discoveries. These nests are noted in Deinsea, the annual publication of the Natural History Museum Rotterdam.

Notably, Moeliker emphasizes that crows and magpies do not simply scavenge for discarded spikes. They actively gather them from buildings, demonstrating innovative behavior in several bird species. Moeliker observed, "They are ripping the stuff off," highlighting their adaptability.

This research aligns with a broader study that revealed nearly 200 bird species construct nests using human-made litter. Dr. Jim Reynolds, an ornithologist at the University of Birmingham, found the anti-bird spike nests impressive yet unsurprising, given corvids' cognitive abilities.

Reynolds remarked on the irony, saying, "To take anti-bird devices and use them to their own ends" demonstrates their intelligence. Beyond nest defense, the spikes might serve as displays to attract mates.

Anti-bird spikes are commonly used to keep birds off buildings. In Bristol, residents attached them to trees to prevent pigeons from perching and creating messes below. Moeliker cautioned against such deterrents, stating, "We should embrace birds and live together with them." He admires crows and magpies and views them as resilient survivors in urban environments.

Earlier, SSP told about why dogs stare intently at us.