This article is over 3 years old

Energy & Environment

Study: Houston Is 2nd Most Dangerous City For Migrating Birds

Millions of birds migrate through the Houston-area skies during spring migration, which spans from March 15 to May 15.

Courtesy of Cornell Lab of Ornithology
A map showing light pollution in the Gulf region.


To embed this piece of audio in your site, please use this code:

<iframe src="" style="height: 115px; width: 100%;"></iframe>

Spring migration is well underway, and the millions of migratory birds that fly through Houston’s skies face one particular challenge: the city's bright skyline.

A recent study by the Cornell Lab of Ornithology ranked Houston as the second most dangerous city in the country for migrating birds, due in large part to its light pollution.

"It’s sort of a combination of at least two things," said Kyle Horton, the study's lead author. "One, Houston’s a fairly large city; it’s quite bright. And then just being a coast city and being on the edge of a primary migratory corridor, many birds are passing through the Gulf region, the Texas coastline."

To create the ranking, the researchers compiled light pollution data with data from radars that tracked bird migration density.

Though the researchers created two separate rankings for the spring and fall migrations, the top three cities – Chicago, Houston and Dallas – were always the same, due to their size and location within major flyways.

Courtesy of Cornell Lab of Ornithology

Horton said millions of birds pass through Houston during spring migration, which spans from March 15 to May 15. The majority of migratory birds in North America — about 80% — migrate at night.

"We’ve known for a while that migratory birds are susceptible to light pollution at night," said Horton. "They become disoriented and distracted with artificial light and it can elevate the risk of them colliding with buildings and other structures."

Horton said further research is still needed to understand why exactly light has this effect on birds.

What You Can Do

The Houston Audubon chapter is one of several across the country that has implemented a "Lights Out for Birds" campaign during peak bird migration in the spring and fall, said Richard Gibbons, the Conservation Director at Houston Audubon.

"Our Lights Out for Birds campaign is asking people to turn out their lights, their unnecessary lights, during the migration period so that we can reduce the amount of risk that Houston poses to these millions of migratory birds," said Gibbons.

Peak spring migration for the Houston-area is forecast to be between April 21 and May 10.

“Lights aren’t always bad, given that migratory birds aren’t always in the airspace,” said Horton. “So turning the lights off or dimming them when possible during the peak migratory season can have a big impact.”

Gibbons said the Houston chapter started looking at solutions after nearly 400 birds crashed into a Galveston highrise in May 2017.

"It was just birds everywhere, and it’s a rare occurrence for it to happen at that scale, and so you begin to wonder, could this have been avoided?" said Gibbons. "We talked with a lot of experts and had a workshop in Galveston to try to learn what actions we could take as a community, and as an organization, as an advocacy group, to make the greater Houston area a safer place for birds."

Individuals or businesses interested in signing up to receive ‘Lights Out’ alerts via email can do so, here.