The environment Packaging from 1994 - Coots recycle plastic
Mars packaging, McDonald's plastic and plenty of Covid masks: Recycled plastic waste enables coots to nest in the middle of big cities. Some nests are even used for decades, as can be seen from old plastic packaging.
08.03.2025, 06:30
SDA
Biologists report on this after analyzing several nests in the city center of Amsterdam in the journal "Ecology". The team led by Auke-Florian Hiemstra from Leiden University collected nests of coots (Fulica atra) in the center of Amsterdam in autumn 2021. While dismantling the clutches, which were largely made of plastic, the researchers came across layer after layer of increasingly older plastic remains.
The most productive was a nest in a canal under a landing site in a hollowed-out metal pipe that reached just above the surface of the water - curiously, opposite the archaeological museum of the University of Amsterdam. Inside, the team discovered 635 plastic remains. More than 200 of these were from food packaging, 32 of which had a decipherable date - and could therefore be dated.
Parts from 1994, 1996, 2020
The oldest plastic parts dated back to the 1990s: a Mars packet refers to the 1994 World Cup in the USA, while some of the many McDonald's packets were from 1996. The upper parts of the nest, on the other hand, were lined with 14 Covid masks, meaning they were from 2020 at the earliest. "The nest tells the entire story of these birds in Amsterdam," says Hiemstra.
Coots actually build their nests anew every breeding season - from natural materials that decompose quickly. According to the study, the birds first entered the city center of Amsterdam, where there is hardly any such building material, in 1989.
Plastic nest lasts forever
According to the study, photos indicate that the nest opposite the archaeological museum has been used for breeding around ten times in the past 30 years - thanks to the plastic waste. According to the team, this saves the birds the time-consuming annual nest building.
According to the study, the only other bird species besides the coot that nests in the center of Amsterdam is the great crested grebe (Podiceps cristatus). It can also build its nest with plastic.
