Trashy Birds: How Coots Are Building Nests with Our Garbage

In the city of Amsterdam, a small black bird called the Eurasian coot has found a clever—if not messy—way to make itself at home. These birds have been nesting in the city since the 1980s, but over the years, their nesting habits have taken a surprising turn. Instead of just using natural materials like reeds and leaves, coots are now building their nests with something much more human: trash.

This year, scientists published a study in the journal Ecology that took a closer look at these unusual nests. What they found was part bird’s nest, part time capsule. The research team collected nest samples and discovered a wide variety of human-made items packed inside—everything from plastic bags and wrappers to fast food containers.

One nest in particular stood out. It appeared to be about 30 years old and had been reused by many generations of coots. Inside, scientists counted 635 pieces of plastic, a candy wrapper from 1994, and even a McDonald’s McChicken box from 1996. It was like a bird-built museum of modern litter.

Why are coots using trash? Experts think part of the reason is that plastic lasts a long time and doesn’t break down like natural materials. This might help the nests stay together longer. But there’s a risk, too. If the birds accidentally eat the plastic or get tangled in it, it could harm them.

More recent nests had an even more troubling sign of the times—layers of used face masks leftover from the COVID-19 pandemic. These masks could be especially dangerous. Coots have large feet, and there’s a chance they could get caught or stuck in the elastic bands.

The study is a reminder of how much our waste affects the natural world, even in ways we don’t always notice. Coots are simply using what’s available, and in cities like Amsterdam, that includes a lot of trash. While it might look creative or even funny at first, the truth is, it shows how closely connected our lives are to the animals around us.

If we want to protect birds like the coot, we need to think more carefully about the trash we leave behind. Our garbage doesn’t just disappear—it ends up in places we might never expect, like a bird’s nest floating in a city canal.