This bird's nest is made of candy wrappers and face masks. Here's what we can learn

In the city centre of Amsterdam, a seemingly ordinary bird nest tells an extraordinary story of human impact on the environment. 

It's constructed from unexpected materials, including sunglasses, earphones, fireworks and even car parts. 

"It's a very special nest, because when we started collecting this nest, or should I say, excavating it, we reached nest layer after nest layer, and with every layer we went deeper in time," Auke-Florian Hiemstra told As It Happens host Nil Kӧksal.

"So it turns out this nest is kind of like a history book, and you could just flip through it going back in time to the start of the 90s." 

The Dutch doctoral student conducted a study published in February focusing on common coots, a type of water bird, and found that these birds use plastic as building material for their nests.

In late 2021, Hiemstra came across a large coot nest in front of Allard Pierson Museum, the biggest archaeological museum in Amsterdam. 

Inside the nest, Hiemstra uncovered 635 artificial items, with the earliest layer containing a Mars bar wrapper emblazoned with a small FIFA World Cup logo from 1994, an event held in the U.S. 

"It's just wild to me, as the wrapper looks so fresh, so new, so the colour pops. You can read the text, yet you know by heart it's 30 years old," said Hiemstra. 

Among the other items found were foil from cigarette packages, a ticket to Amsterdam's National Maritime Museum and a number of fast food remnants from McDonald's.

"For a while … it kind of felt like I'm a McDonald's archeologist, just studying wrappers and lids and sauce," he said. 

There was also a more somber discovery: around 15 face masks from the COVID-19 pandemic were buried in the nest. 

This unusual collection of modern trash has given Hiemstra more than just a snapshot of the birds' nesting habits — it has allowed him to trace the environmental history of the area. 

By analyzing the expiry dates on the packaging, Hiemstra has created a "perfect timeline" of this particular nest site. 

"Like stratigraphical layers, geological layers on top of each other, being able to get this full picture of around 10 breeding attempts in the last 30 years," he said.