Birds are building nests with plastic, and the consequences are deadly

A new study shows how everyday waste – like ropes and plastic bags – is silently killing baby birds, not just in the oceans, but on land too.

Researchers spent four years tracking white storks in southern Portugal. What they found was brutal: plastic-filled nests, chicks caught in rope, and many young birds that didn’t survive.

Bird nests built with trash

The research was led by scientists at the University of East Anglia, along with teams from the University of Montpellier and the University of Lisbon.

The team focused on white storks – large, land-dwelling birds that often build their nests near people. And those nests? They were filled with trash.

The researchers inspected 568 nests from 32 colonies in Portugal’s Alentejo and Algarve regions. Of those nests, 91 percent contained human-made debris – mostly plastic.

Soft plastic like shopping bags was found in 65 percent of nests. But the bigger danger was rope. Nearly half the nests had it, and it was the top cause of fatal entanglement.

In one especially detailed year of the study, scientists visited 93 nests weekly. They found that 12 percent of the chicks became tangled in debris – many fatally.

Chicks caught in cords

Most of the ropes came from agriculture – specifically, baler twine made of polypropylene.

This tough plastic rope is used to bind hay bales, but it doesn’t break down easily. Once it ends up in the environment, birds collect it for their nests. The consequences are often deadly.

In 63 percent of cases, entanglements were caused by ropes. Some nests contained as many as 22 separate ropes. Baler wrap, another plastic material used in farming, showed up in 13 percent of nests and entangled six nestlings.

White stork chicks in nests with more rope were more likely to get stuck. And once entangled, their chances of survival dropped dramatically.

The plastic nest problem

“This is a serious issue,” said Professor Aldina Franco of the University of East Anglia. “These chicks get entangled in synthetic ropes when they are very young and the ropes slowly strangle their limbs as they grow – mostly legs and feet – leading to necrosis and amputations, they suffer a horrible death.”

It’s not just happening in Portugal. According to Franco, birds across Europe are weaving plastic waste into their nests.

In Ukraine, soldiers have reported nests containing drone wiring. In the UK, small birds like goldfinches and wrens are building nests with colored plastic threads.

“We show that the impact of plastic in the nests can be underestimated, because the negative effects of the ropes and other human-produced materials tend to happen in the early life of the chicks, at an average age of two weeks, and the deaths can go unnoticed,” said Professor Franco.

Storks signal wider threat

White storks are what scientists call an “indicator species” – meaning they can signal a wider environmental problem. If this many of them are getting trapped in plastic, other birds likely are too.

“This study suggests that the threat posed by human-derived materials to terrestrial birds may be far more severe than previously recognized,” said lead author Ursula Heinze of the University of East Anglia.

“Our findings offer new insights into the extent of nestling deaths caused by entanglement, and highlights the urgent need to remove and replace hazardous materials such as polypropylene baler twine from both agricultural use and the environment, given its harmful impacts on nestlings.”

While past research has looked at the presence of plastic in nests, this study went a step further. It tracked chicks from hatching to fledging, allowing scientists to see exactly when the entanglements occurred.

“Our main goal has been to identify the nesting materials that may pose significant risks to terrestrial bird species and pinpoint their origins, in order to develop effective strategies to mitigate these risks to wildlife,” noted Professor Franco.

Mistaking trash for twigs

Why do birds use plastic in the first place? According to Dr. Inês Catry from the University of Lisbon, white storks are known to incorporate discarded human-made materials into their nests, frequently nest near or within human settlements and often forage on organic waste at landfill sites.

“The reasons for using these materials in nest-building are not fully understood but may relate to their availability and the scarcity of natural ones, while some might also be mistaken for food, being inadvertently incorporated in the nests,” said Dr. Catry.

“This study highlights that plastic pollution in terrestrial environments needs to be addressed and solutions to replace or safely discard of hazardous materials are urgently needed.”

Land birds face plastic threat

The study’s message is clear: plastic pollution isn’t just a marine problem. It’s affecting life on land in painful, visible ways. And even common farming tools like baler twine are part of the problem.

If these findings are ignored, more birds will suffer. However, if people and industries take responsibility – by cleaning up, switching materials, and being more aware – there’s a chance to stop these deaths before they happen.

The full study was published in the journal Ecological Indicators.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–