Divya Anantharaman shines her flashlight under the wooden benches near a building on Wall Street. Right now, the streets of New York are still the exclusive domain of early risers. But starting her weekly search-and-rescue mission at that time, early in the morning, is essential, she says.
She searches for the victims of the notorious bird killers: the glass skyscrapers. When daylight comes, the porters sweep the sidewalks, and the evidence is lost.
​Anantharaman is a volunteer with NYC Audubon, an urban conservation group that monitors bird deaths due to window collisions. She inspects every dark corner of the route, in potted plants and flowers, carefully so as not to lose victims that can be rescued. At the end of the round, she finds a dead bird under a glass overpass that connects two buildings.
It is a bird called “American woodcock” (American woodcock), she believes, a relatively common, long-beaked migratory bird. Every spring, woodcocks fly to New York after spending the cold months in Alabama and other states along the southern Gulf of Mexico coast. This bird is stiff, which means it died recently, says Anantharaman. “The eyes are still so clear. That could have been a few minutes ago.” She snaps pictures, takes a solemn moment to close the bird’s eyelids with her thumb, and places the corpse in her pink backpack.
A billion birds and counting
Every year, between 90,000 and 230,000 birds land near New York buildings, according to NYC Audubon estimates. The city’s concentration of illuminated buildings is a dangerous obstacle for winged travelers, especially during spring and autumn migration seasons.
New York is situated on a migration route to South America, where many birds spend the winter. As birds navigate by looking at the stars, the artificial light of the night attracts and disorients them. Believing they are flying towards starlight, the birds veer off course and land in the middle of an unknown metropolis.
“The biggest problem is the reflective glass,” says NYC Audubon biologist Kaitlyn Parkins. “Birds don’t see the reflection of a tree. To them, it’s a tree. They fly towards these ‘trees’, they can accelerate very quickly and often die immediately.”
In the United States, where most research on bird strikes has been carried out, buildings are responsible for the death of up to 1 billion birds a year, according to calculations made in the 1990s by pioneering ornithologist Daniel Klem. Glass windows, however, are traps for birds all over the world.
“Birds are vulnerable to glass wherever there are birds and glass together. They don’t see these things,” says Klem, who adds that it’s not skyscrapers, but low- and mid-rise buildings that pose the biggest threats.
Klem, who is currently a professor at Muhlenberg University in Pennsylvania, considers window collisions as critical to bird conservation: “As a threat, I would put the collision right after habitat destruction. kill indiscriminately. They are also the most suitable for the population. We cannot afford to lose any specimens, much less good breeders”.
an international problem
In recent years, conservation groups and scientists have taken up the cause. Binbin Li leads one of two window collision monitoring groups in China. She is an assistant professor of environmental science at Duke Kunshan University and earned her doctorate from Duke in the US, where she met the lead researcher on the bird collision project.
“At first I thought this was just a problem at Duke, or in the US. I couldn’t imagine seeing it here in China,” he says. But upon her return, she received reports of three dead birds on campus within a month.
With a group of students, she now counts dead birds on campus in Suzhou. Many of the victims, she notes, are found under glass corridors, like the woodcock Anantharaman found in New York.
Li started a national survey to get a clearer picture of the problem. Three major migration paths cut through China, but data on fatalities along these routes are still limited. “We realized that bird strike is not well known in China, not even in academia,” says Li.
‘Just change the glass and turn off the lights’
In Costa Rica, Rose Marie Menacho had to convince her professors to let her investigate bird strikes as a doctoral student eight years ago. “They didn’t know much about it, they didn’t know it was a real problem. Even I was a little shy when I said I was studying it. I was a little embarrassed because I thought it wasn’t such a big deal,” she recalls.
To understand the scale of the problem in the tropics, she now works with around 500 volunteers. Some store bird carcasses in their freezers, others send reports and photos. “It’s not just migratory species that collide,” says Menacho. Her volunteers retrieved resplendent quetzals and brightly colored toucans with flamboyant, long beaks. Both are local species.
“The collision kills a lot of birds that already have to deal with habitat loss, climate change, pesticides, etc. And it’s so easy to fix, just change the glass and turn off the lights,” says NYC Audubon biologist Kaitlyn Parkins.
With the data collected, Parkins and his team are trying to convince building owners to take action. Typically, they do not need to replace any glass. Special films can make it less reflective – and thus save energy for heating and cooling. The marks on the windows can help the birds perceive the structure. One example: after a renovation of the Javits Convention Center, volunteers found about 90% fewer dead birds around the building.
In January, New York City adopted legislation to require public buildings to turn off lights at night during migration periods. Since last year, architects must also use bird-friendly designs for all new buildings, such as the ultraviolet coating on glass, which is visible to birds, not humans.
New regulations are a good start
On the sidewalk in front of Brookfield Place, a massive office and shopping center in lower Manhattan, Rob Coover inspects a small bird. Daylight is still scarce, but he’s been looking for dead birds for half an hour.
Coover peers carefully behind the stacks of chairs that cafe workers will soon distribute on the terrace. On two occasions, he has squirmed to take pictures of a tiny, still stiff corpse. Now, he again takes rubber gloves and plastic bags out of his backpack to collect and preserve a victim.
Coover once found 27 birds in just one morning. A volunteer partner made international headlines when she spotted 226 lifeless birds around One World Trade Center in just one hour last September.
“It’s pretty depressing, all these dead bodies,” says Coover. Sometimes he finds a survivor and takes the injured animal to a bird refuge. The corpses are usually left in his freezer until he has time to take them to the conservation group’s headquarters, where they are grouped and, some of them, distributed to museums. “Before the pandemic, I used to go to work after my rounds and put the birds in the office freezer,” he says. Nobody ever noticed them, he adds.
In the United States and Canada, volunteers are active in many communities, and the list of local governments that enact laws to protect birds in buildings is growing. According to the nonprofit American Bird Conservancy, New York’s law is one of the most effective. After studying bird strikes for nearly half a century, Daniel Klem is satisfied. He finally sees the growing awareness he’s been waiting for.
“Climate change is also a very serious issue, and nobody is interested in letting go of it. But it is very complex, and it will take time to figure things out and convince people to do things responsibly. Bird strikes are something that we could solve tomorrow. It’s not complex, we just have to be willing”, he concludes.
