New York City’s US $2.6 trillion worth of real estate is having a devastating impact on some of its smallest inhabitants.
It's estimated close to two million birds can migrate across New York state in a single night, but many are becoming lost after being drawn from their migratory paths by Manhattan’s bright lights. Others drop to the ground stone dead after flying into glistening windows.
Just under a quarter of a million birds die across the city each year after smashing into glass. An interactive map project curated by NYC Audubon — a grassroots bird protection network — collects data from the public and marks each collision with a tiny dot. Yellow means injury and orange is death.
At the time of reporting 2588 bird collisions had been documented on the map in 2022. This figure eclipses the 1872 recorded in 2020 is and slightly up on 2021 when 2210 birds were logged. The increase is likely due to growing awareness of the project and people returning to the streets and finding birds as the Covid-19 threat declines.
Dustin Partridge, director of conservation and science at NYC Audubon told Yahoo News Australia it’s a “huge issue”. Across the entire country, over 1 billion birds die from collision, second only to domestic animal-inflicted deaths at 2.4 billion.
“They get into this urban inhospitable environment with impervious surfaces and glass and they end up colliding,” he said. “They see a nice tree nearby and they fly into it. Turns out it’s just a reflection. They can’t pick up the cues that we can.”
Around three-quarters of New York’s bird deaths occur in autumn, while most others happen in the spring. One reason behind this is that young birds are working out their migratory routes.
Video from a mass bird death event in 2021 gives an insight into the problem, showing a volunteer picking up carcasses every few steps. In text accompanying the 35-second clip, she tweets: ‘Can we please turn off the lights during migration?”
Why lights are killing birds across New York City
The city's numerous skyscrapers have a deadly effect on birds.
"Migratory birds have really evolved to use the moon, the stars and other cues to migrate at night," Mr Partridge said. "All of a sudden, we have these bright buildings that are lit up throughout the night during migration."
While some building owners have been responsive to limiting lights during migration, there are some displays that are unavoidable. One of the most disruptive light displays is the September 11, Tribute in Light display. It consists of 88 vertical searchlights which shine into the sky to remember victims of the 2001 World Trade Centre terrorist attack.
The display is believed to endanger around 160,000 birds each year. Combatting its devastating impact, monitors from NYC Audubon now watch the site overnight.
“We're monitoring the lights for too much of a build-up of birds. And if they build up to a certain point, we shut the lights out,” Mr Partridge said. “These birds are literally flying in from migration from maybe as far away as New Jersey. They're getting drawn into these beams, and they get stuck in the beams, circling for hours, dropping lower and lower. It’s really alarming.”
The lights are shut down for around 15 minutes, allowing the birds to recover and fly away. “It's a really good example of how powerful light really is,” Mr Partridge said.
What species of birds are being killed?
Over 300 bird species visit New York City each year, but some are more prone to collision than others. They include the American woodcock and the white-throated sparrow.
European starlings, black pigeons and European sparrows have evolved to live in cities, but it's those migrating through that don't do well as they are used to living in green spaces.
Are birds more likely to collide with skyscrapers?
While many people would expect skyscrapers like Manhattan’s Steinway Tower to be most impactful, there have been few bird casualties since it was constructed in 2020. The US $2 billion building is set back a couple of blocks from Central Park, lessening the likelihood of its reflection drawing in birds from nearby trees.
Nearby collision hotspots include Columbus Circle and the northwest corner of Central Park, and that’s because the buildings are highly reflective. It’s lower levels and even glass walkways often prove deadly to birds.
Combatting the problem, NYC Audubon has successfully campaigned to ensure all new buildings have bird-friendly glass on the lower 75 feet (23 metres) or 12 feet over green spaces. But with much of the building stock very old there is still a lot work required to bird-proof the city.
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