Birds Around the World Are Building Their Nests With Trash

A new study has found that 176 bird species around the world are building their nests with trash from humans, such as cigarette butts, candy wrappers and plastic string. Birds on all continents except Antarctica were found to make nests with this waste, which could harm the birds and the chicks.

Researchers analyzed nearly 35,000 nests and found human-generated trash in the nests of many types of birds as this waste becomes more ubiquitous on land and in marine environments. The study was published online in a special issue of the journal Philosophical Transactions of the Royal Society B.

“A wide variety of bird species included anthropogenic materials into their nests,” Zuzanna Jagiełło, an ornithologist at the University of Warsaw and lead author of the study, said in a statement. “This is worrying because it is becoming increasingly apparent that such materials can harm nestlings and even adult birds.”

The study found that some species used particular types of waste. Blackbirds used plastic string or plastic bags to build up their nests, and storks had nests built in part with plastic string as well as cardboard and foil, The Guardian reported. Seabirds were found to add fishing nets, and birds in cities in South America added cigarette butts.

Although some of these materials may offer benefits, such as plastics that help better insulate the nests or cigarette butts that contain compounds to repel parasites, these waste pieces are also dangerous to the birds and their chicks. Chicks can choke on the trash when they mistake it for food, plastic strings can entangle the birds, and some trash can introduce toxins to the nest, exposing the birds to harmful chemicals. Brightly colored trash may also attract predators to the nest.

The scientists have theorized that birds may be using certain types of trash to attract mates, but they haven’t found links between bird age or nest placement with specific waste items.

The study authors said more research is needed to find how many more bird species are using trash to build nests. The researchers are also calling on citizen scientists for help furthering the research.

“Birds are wonderful bio-monitoring tools,” Jim Reynolds, study co-author and an ornithologist at the University of Birmingham, told The Guardian. “We’re asking people to show an interest in this and go and take a photograph of a nest in their garden, wherever they might live.”