Light pollution confuses birds as they fly south

Since most birds migrate at night, light pollution can cause birds to become disoriented and attracted to urban centers where they be killed by flying into buildings. Photo courtesy Reinout Dujardin/Pixabay

The Dallas-Fort Worth area is the third most dangerous area in the United States for migratory birds to travel through, according to the Texas Conservation Alliance.

Since most birds migrate at night, light pollution can cause birds to become disoriented and attracted to urban centers where they be killed by flying into buildings.

It is estimated that one in four migratory birds – as many as 1 billion each year — die from collisions with buildings every year.

Conservationists urge Texans to turn off nonessential lighting between 11 p.m. and 6 a.m. during the fall and spring migration seasons.

Texas is home to three out of the top 10 cities that pose the greatest light pollution risk to migrating birds, said Tania Homayoun, Texas Parks and Wildlife Department nongame ornithologist.

“Taking action can be as easy as flipping a switch, closing curtains or blinds, or committing to dark-skies-friendly lighting in the places we live, work and play,” she said.

The full fall migration period began Aug. 15 and runs through Nov. 30, with the critical peak migration period Sept. 5 through Oct. 29, according to Texas Audubon.

The full spring migration period is March 1 through June 15 with the critical spring peak migration period from April 22 to May 12.

Texas is on the Central Flyway, a migration corridor shaped like an hourglass: wide at the northern end, narrowing through Nebraska, and then widening as it passes through Oklahoma and Texas. Nearly 2 billion birds comprising 300 species traverse Texas during the migrations.

The “Lights Out, Texas!” program was established in 2017 to focus on urban communities.

According to bird migration forecast maps, nocturnal migration reports begin three hours after local sunset and are updated every six hours by Colorado State University, UMassAmherst and the Cornell Lab of Ornithology. The interactive maps are live at https://birdcast.info/ .

The “Lights Out” program has been credited with producing 11 times fewer bird collisions during the spring migration and six times fewer collisions during the fall migration.

Research has found Chicago was the country’s deadliest city for migrating birds, followed closely by Houston and Dallas-Fort Worth. That data is based on the work of volunteers who collect birds that died as a result of light pollution. The conservation alliance, tcatexas.org, coordinates the effort to send birds to the Biodiversity Research and Teaching Collections in the Department of Ecology and Conservation Biology at the Texas A&M College of Agriculture and Life Sciences.

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