Cutting lights might help migrating birds
Texas plays a crucial role along the migratory paths of nearly 2 billion birds each spring and fall. Light pollution from cities across Texas, though, can make the trek of migratory birds more treacherous, especially during times of inclement weather.
Nearly 33% of migrating birds pass through Texas during the spring, while 25% fly over the state during the fall, according to BirdCast, an organization dedicated to forecasting and analyzing bird migration. What makes Texas so unique?
“Texas is in a great place. We are right in the central flyway, so when birds are migrating south to north or north to south, many of them pass through Texas,” said Chloe Crumley, public affairs and engagement manager for Audubon Texas. “The benefit of Texas is we have a lot of vegetation and habitation types. So we have one of the most diverse variety of birds you can see right here in Texas.”
Birds aren’t just using Texas as a beacon in their migrations. The Texas A&M Natural Resources Institute found that birds contribute significantly to the economy of Texas. In the Rio Grande Valley, nature tourism and bird-watching contributes $300 million to the economy and supports more than 4,400 full- and part-time jobs annually.
Problems for birds
Even in an airplane, the idea of traveling thousands of miles probably doesn’t seem all that fun, regardless of the destination that awaits you when you land — and migrating is not an easy task for birds.
First, U.S. bird populations are shrinking. We’ve seen a net loss approaching 3 billion birds, or 29%, since 1970. Add to that the estimated 1 billion bird deaths that occur in the United States every year from collisions with buildings and structures, and the picture becomes even more stark, especially for migratory birds.
Attraction to and disorientation from light pollution is a significant problem facing birds that migrate through Texas, contributing to their concentration in urban areas.
“What ends up happening is birds get exhausted, they land in our communities and then are faced with other urban threats, like cats or window collisions,” Crumley said. Once birds land in large cities, the risk they face by colliding with reflective glass in commercial and residential windows increases.
Surprisingly, birds aren’t most at risk for window collisions with the tall skyscrapers that shape the skyline of Houston.
“We actually see birds colliding most with buildings that are two to five stories tall,” Crumley said.
When migratory birds land in our communities, they can’t resume their journey at 20,000 feet. They have to gradually get to that altitude, and that puts them in serious danger of colliding into windows, particularly the windows of smaller commercial or residential buildings.
What can be done to help birds along on their long and tiresome journey? That’s where Lights Out Texas comes into play.
What is Lights Out Texas?
“The whole concept behind Lights Out has been around since the 1990s,” Crumley said. But an event in Southeast Texas during one of the spring migrations renewed awareness about the perils migratory birds face during their long journeys.
“In 2017, the beginning of Lights Out was spurred by a mass collision in Galveston where about 400 birds collided with a building,” Crumley recalled.
That building, the 23-story One Moody Plaza, headquarters the American National Insurance Co., which took steps to mitigate light pollution after the May 2017 incident.
The collaborative effort of many groups, including Houston Audubon and the Cornell Lab of Ornithology, resulted in the statewide initiative to protect birds from light pollution: Lights Out Texas.
During fall 2020, Mayor Eric Johnson proclaimed that the city of Dallas would go “lights out” to help bird migration. Houston Mayor Sylvester Turner proclaimed Lights Out Nights in April 2021 and encouraged residents and businesses to turn off nonessential exterior lighting from 11 p.m. to 6 a.m. Some of Texas’ largest cities have passed proclamations recognizing “lights out,” but you can do other things besides just flipping the switch on nonessential lighting.
Crumley said it’s as easy as getting outside and soaking in the sights and sounds of the nearly 2 billion birds that migrate through the Lone Star State each year.
“We encourage people to, if they’re not already birding, to go outside and see what kind of birds are migrating through Texas right now and to play a role in Lights Out,” she said.
Do you want to do more? There are even communities that have volunteer bird-monitoring programs in place to estimate the number of migratory birds and the nightly collision rate. When it comes to raising awareness about migratory birds and the difficult journeys they embark on twice a year, it really is a collaborative effort for all Texans.
Role of weather
Weather plays a significant role in bird migration across the country. During the overnight hours Wednesday, a major bird-window collision took place in Chicago during adverse weather conditions. The mass collision of May 2017 in Galveston is thought to be related, at least partially, to inclement weather.
“A front was coming in that pushed the birds further down. Instead of being at about 20,000 feet above, they were closer to 5,000 to 7,000 feet and crashed into a building,” Crumley said.
Migratory activity tends to decrease during frontal passages and increase after the front passes. Occasionally, migratory birds will “fall out,” or wait out the passage of a cold front. Birders get a chance to see those migratory birds up close during a pre-front fallout event. Birds will continue their journey when weather improves, typically upon the arrival of high pressure and a stout tailwind.