Plastic collected in bird nests is tiny time capsule

Birds are urban foragers in the most complete sense. I once found a nest in my backyard with a piece of dark blue wool I had been using to knit a scarf for a loved one. That made my heart warm. But when the winds blow in the spring, the old birds nests in my city come loose and I find all manners of plastic bits in their nests from construction sites to wrappers from food. That makes my heart sad. Especially with so much plastics being found in the human body.

Auke-Florian Hiemstra, a scientist from Holland, is looking into the nest of urban birds and is finding the most unusual wrappers, some going back decades in time. He’s like an urban archeologist, understanding how birds construct their nests and reuse materials year after year. One nest, from a Eurasian coot (Fulica atra), was retrieved from an Amsterdam canal with layers going back 30 years in time: the outer layers contained several face masks from the pandemic, while the base held a Mars bar wrapper promoting the 1994 FIFA World Cup.

The discovery sheds light on the growing interaction between urban wildlife and human-made materials, a trend that has intensified in recent decades. Birds, particularly in cities, are increasingly incorporating plastic and other human debris into their nests. He has even found bird nests made from anti-bird spikes. “Even for me as a nest researcher, these are the craziest bird nests I’ve ever seen. Today my paper came out on this rebellious behaviour. And it’s like telling a joke…”

Typically, coots build new nests each year, but in urban areas, “reusing the foundation of older plastic nests may save time, giving the birds more opportunities to forage or defend their territory,” says Hiemstra. However, he adds, “These face masks — part of our pandemic layer — pose a serious hazard for coots, especially with their large, dinosaur-like feet.”

This can offer practical benefits, such as reusing the structural components of old nests, which can save valuable time and energy. Yet, these materials also come with risks. While the plastic may be convenient, it is not biodegradable and poses a long-term hazard to the birds.

The face masks found in the nest are particularly concerning, as they can entangle or restrict the movement of the coots, especially given their large, heavy feet. This poses a significant danger, as entanglement can affect the birds’ ability to forage for food or escape from predators.

Furthermore, the accumulation of plastic in natural habitats is a growing environmental issue, with animals unknowingly ingesting or getting trapped in discarded plastic materials. Trump brings back the plastic straw is a win for some, a loss for wildlife.

The researchers are calling for more awareness of this issue, urging urban planners and environmentalists to consider the impact of waste on local wildlife. As human society produces ever more plastic waste, it is essential to find ways to mitigate its effects on the ecosystems that share our cities.

Hiemstra hopes that this study on birds nests will encourage more research into how wildlife adapts to urban environments and the materials they encounter there, while also highlighting the need for better waste management and conservation efforts.

Hiemstra, together with his girlfriend Liselotte Rambonnet and a team of volunteers, takes to the city’s canals every week to rid them of plastic waste. He has also written a children’s book about animals in the city.