Every year, billions of birds die during migration. Dark cities to protect migrating birds could help save them.
Every spring and fall, I watch the skies in a slightly different way. Living in Canada, I’ve grown up surrounded by birds—warblers in the garden, robins singing at sunrise, and geese honking overhead in perfect formation. But what I didn’t know, until a few years ago, is how many of them don’t make it.
They crash into buildings in cities like Dallas, where the skyline glows all night and towers are wrapped in glass. They travel thousands of miles, crossing oceans and deserts, only to be stopped by a window. That’s why more cities need to go dark—dark cities to protect migrating birds are a simple, proven way to save lives.
The first time I learned about bird collisions, it hit me hard. I saw photos of small birds in Texas, some as light as a coin, lying lifeless on the pavement. They looked like they were just resting—legs tucked in, feathers still perfect. But they were dead.
In Dallas, this happens every night during peak migration. The city is situated directly on the Central Flyway, a major migratory route for birds travelling between North and South America. In spring alone, about one in every three migrating birds in the U.S. passes through Texas. That’s billions of birds flying at night, using the moon and stars to guide them.
But cities like Dallas light up the sky, and that confuses the birds. They fly toward the glow, circle in disoriented loops, and crash into glass buildings. It’s estimated that up to 1 billion birds die this way every year across the U.S.
That’s why volunteers with Lights Out, Texas! walk downtown before dawn, collecting the bodies. Since 2020, they’ve found over 100 species in the streets: sparrows, warblers, doves, even rare ones like woodcocks and lazuli buntings. Last year, they logged 295 birds in Dallas alone—and that’s just the ones they found.
I may live in Montreal, far from Texas, but many of the same birds that pass over Dallas also fly over my neighbourhood. They nest in our parks, rest in our backyards, and return every year. If they don’t survive the journey through bright cities in the U.S., we never get to see them here.
A single songbird can raise up to 36 chicks in a year. So, losing one bird on migration can ripple into hundreds more never being born.
We’ve already lost nearly 3 billion birds in North America since the 1970s. Almost a third of bird species in the U.S. are now at risk. And while big threats like habitat loss and climate change take time to fix, making dark cities to protect migrating birds is something we can do right now.
Some cities are starting to act. In New York, officials dim the bright 9/11 Tribute in Light when too many birds get trapped in its beams. In Chicago, McCormick Place, a massive convention center, installed bird-safe glass after 1,000 birds died there in one night in 2023. The following year, collisions dropped by 90%.
Even in Dallas, a few buildings have taken steps. The Perot Museum added bird-safe glass during renovations. Reunion Tower dims its lights during the peak migration season. But many buildings, including the city’s convention centre, are still deadly.
That building has dark glass, stands of trees nearby, and sits directly in a migratory path. It’s undergoing renovations, and local groups are pushing hard for it to use bird-safe materials. They’re also calling for city-wide policies to turn off lights during migration season.
See also: Reducing Light Pollution
But progress is slow. LED lights, now used almost everywhere, are cheaper and more energy-efficient—but they’re also worse for birds. Bird-safe glass costs more than regular glass, which makes developers hesitate. And let’s be honest—changing how a city looks at night takes political will.
If we want to prevent this from happening again, we need dark cities to protect migrating birds. We need buildings that don’t trick birds with reflections. Lights that don’t lead them off-course. And people who care enough to speak up.
It doesn’t have to be expensive or complicated. It can start with just turning off outdoor lights at night during migration and using blinds or curtains and supporting building codes that require bird-safe glass. Asking local governments to do better.
The truth is, birds are running out of safe skies. But we still have time to fix it.
We can help keep their path clear.
We can build cities that shine less and save more.
