Texas' skyscrapers are going dark to keep billions of birds safe
About two billion birds fly through Texas in the spring – and lit-up buildings pose a deadly risk. Turning out the lights at night could save countless fatal collisions.
It was a foggy Thursday morning when animal services supervisor Josh Henderson received news of a mass mortality. On May 4, 2017, 395 migratory birds died after smashing into one office tower in Galveston, Texas. Henderson rushed to the scene to witness the gruesome spectrum of feathers from yellow and orange to blue and grey of the lifeless small-featured bodies.
Most of them were warblers: small, bright, colourful birds that are particularly abundant in Texas. They had been on their homecoming spring migration, an epic journey that takes them from wintering sites as far south as Mexico to nesting sites as far north as Canada, according to the National Audubon Society, a US-based bird conservation group.
For birds, Texas is a major flyover state: approximately two billion birds, or one in three birds migrating through the US, fly through the Lone Star State in the spring. It is snugly situated at the convergence of two major migratory flyways – the broad north-south routes that many different bird species all use to migrate. Both the Central Americas Flyway, which stretches from the Canadian Arctic to the southern tip of Argentina, and the waterway-rich Mississippi Flyway, beloved by migratory waterbirds, pass through Texas.
Along the route, hazards abound – including bright city lights. Though the Galveston collision was a particularly dramatic example, birds hitting buildings is a common phenomenon. Every year, between 365 million and one billion birds are thought to be killed in building collisions in the US. The risk increases when they migrate and pass through cities in large numbers.
More than half of those fatal crashes are actually with low-rise buildings, such as people's homes. Birds may collide with them in small numbers per building, but it adds up, as houses are so widespread. However, as the Galveston case and mass bird crashes in other US cities show, big lit-up buildings such as skyscrapers, convention centres and office blocks can pose a disproportionate threat, killing hundreds of birds at once, because of each building's sheer scale. In October 2023, nearly 1,000 birds died in a single night during their autumn migration from striking a lakeside convention centre in Chicago.
The scene of the mass collision in Galveston was a 23-floor skyscraper called One Moody Plaza. The tallest building in downtown Galveston used four corner spotlights pointing straight up in the sky and a glowing green halo of LED lights around the top of the tower.
The influence of artificial light in urban spaces is a well-known phenomenon among birds, but is still not fully understood. Birds tend to migrate by night, and use the stars to navigate. By day, they use the position of the Sun to orient themselves. During nocturnal migration, they are often seen gathering around or crashing into lit-up windows and structures, or gathering around beams of projected life. The artificial glow of cities also appears to attract them for stopovers. One explanation is that they may generally fly towards light sources, but also, that the artificial light confuses, traps and disorients them.
The accident prompted Houston Audubon, a bird conservation organisation, and American National Insurance Company, which occupies the building, to take action and jointly develop a science-based response.
At the time, several existing, successful campaigns in the US and Canada encouraged building owners, developers and businesses to switch off non-essential lighting to help travelling birds. One was Toronto's Fatal Light Awareness Programme (FLAP). The National Audubon Society also had Lights Out campaigns in several cities and states, which encouraged businesses and individuals to switch off unnecessary outdoor lights at night.
However, protecting species that move presents special challenges for researchers and conservationists, compared to protecting a resident population, Farnsworth points out. Migrating birds can travel thousands of kilometres, crossing and stopping in many different habitats, traversing borders, and flying through cities – which are continuing to grow around the world, with urban sprawl replacing and fragmenting birds' habitats.
Farnsworth suggests that given this complex picture, there is no single solution to helping migrating birds. Instead, in his view, spreading awareness, empathy and efficient enforcement are all crucial in keeping them safe and avoiding collisions. "We need to keep our connection to nature through our eyes, ears, nose, whatever – and use senses to experience the core of all this research and observation."
Bbc.com
