AILSA CHANG, HOST:
Each year, hundreds of millions of birds die after colliding into buildings. Scientists say one reason is because of light pollution from cities. Now, researchers are using weather radar to track migrations. And as Seth Bodine of member station KOSU reports, the hope is to predict and prevent collisions.
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SETH BODINE, BYLINE: Birds chirp as Scott Loss walks around buildings at Oklahoma State University. He has a notepad in one hand and a bird identification book in the other.
SCOTT LOSS: This is one of the 16 buildings that we monitored.
BODINE: Loss is on a team of researchers studying bird collisions into buildings like this one at the Noble Research Center. He points out features of the building that make it one of the biggest bird killers that they've studied.
LOSS: Looking up here, you can obviously see really extensive large panes of glass, entire facades of the building covered with glass.
BODINE: Loss says birds don't see glass very well, and buildings like this are problematic. He estimates up to 1 billion birds die every year in the United States after building collisions. That has researchers worried. Loss says bird populations have declined in the past 30 years, and that's not good for the environment.
LOSS: Birds have a tremendous value to ecosystems and their functions. They're pollinators. They're seed dispersers. They control certain undesirable insects and other pests.
BODINE: Researchers think using radar technology to track birds flying at night could be part of the solution to help save them. When large flocks are seen migrating across the country, cities can be given a heads-up to dim lights. As Loss looks at a computer screen, he explains how the colors on the map are similar to a weather forecast.
LOSS: Just like with precipitation, the color scale represents intensity of the radar return. With heavy precipitation, you get the darker greens, the yellows, the reds. With heavy bird migration, you get the same.
BODINE: Conservation efforts are already playing out in Texas with a pilot project called Lights Out Texas. The Cornell Lab of Ornithology is partnering with politicians and local conservation groups to encourage residents and businesses to dim non-essential lights in major cities like Dallas, Houston and Austin. Millions of birds travel every night in the spring and the fall using stars and the Earth's magnetic field to guide them from place to place. Sirena Lao works at the San Francisco Bird Observatory. She says light pollution throws those guiding senses off.
SIRENA LAO: Birds are kind of driven off course by light pollution. They're often attracted to bright city lights. So birds will kind of veer off course and fly towards these cities, which, you know, leads them to even more hazards.
BODINE: Researchers think dimming lights might make a difference. Jared Elmore is a lead author of a study that found the number of collisions could be predicted by how many birds migrate at night.
JARED ELMORE: And we saw a lot of birds coming through the airspace, and they were migrating at lower height. We would expect, you know, a higher number of collisions to occur.
BODINE: Bird experts hope the radar technology could be used to help inform public policy. In Texas, the conservation project wraps up next month. Researchers will analyze the collision data collected by volunteers to see how effective the Lights Out program was in reducing bird deaths. For now, scientists hope turning down the lights will make a difference.
For NPR News, I'm Seth Bodine in Oklahoma City.
(SOUNDBITE OF THE COMET IS COMING'S "THE SEVEN PLANETARY HEAVENS") Transcript provided by NPR, Copyright NPR.
