by Nicole Rivard

As a volunteer for Lights Out D.C., Lisbeth Fuisz roamed a four-mile route in downtown Washington, D.C. in May inspecting buildings and collecting dead or injured migratory birds who had collided with the structures. In cities like D.C., migratory birds can be lured by artificial lights or become disoriented by smooth, transparent surfaces and slam right into glass buildings and towers.

The mission of Lights Out, a program started almost a decade ago by the non-profit City Wildlife, is to collect information that can be used to convince building owners and managers to adopt light abatement procedures for the sake of migrating birds.

When her hour-and-a-half shift was over, Fuisz had collected five dead birds.

“By D.C. standards, that’s quite a few birds to find in one morning. However, there are other cities with much larger problems than ours,” she said.

Fuisz is right. According to a study released in the spring by the Cornell Lab of Ornithology, the five most dangerous cities for birds during spring migration are: Chicago, Houston, Dallas, Los Angeles and St. Louis. During fall migration, they are Chicago, Houston, Dallas, Atlanta and New York. The study combines satellite data showing light pollution levels with weather radar measuring bird migration density.

The study’s aim is to raise awareness that bird strikes are not isolated events; they are part of a global problem that everyone—from architects and city building managers to homeowners—is responsible for solving. The study highlights artificial light at night as a contributing factor. Songbirds, especially warblers, seem most susceptible to light pollution. Building glass is the other major threat to birds, as it can be so clear that birds don’t see it, or it can reflect nearby trees, duping birds who then fly into it.

But the good news is, it’s an environmental issue with relatively easy solutions compared to something like climate change, which can be so overwhelming that the public feels paralyzed instead of motivated to take corrective action.

“The purpose of the study is to make some on-the-ground change happen,” said Kyle Horton, lead author of the study. “We’re trying to use forecasting on birds who are flying to create awareness and motivate people to change their behaviors.”


Horton pointed out that because many birds alter their migration routes between spring and fall, rankings of the most-dangerous cities change slightly with the season. During spring migration, billions of birds pass through the central U.S. between the Rockies and the Appalachians, so cities primarily in the middle of the country comprise the most-dangerous list for that season. Heavy spring migration along the West Coast also puts Los Angeles on the spring’s most-dangerous list.

Fall bird migration tends to be intense along the heavily light-polluted Atlantic seaboard, which is why four eastern cities make the list in autumn when the sun goes down earlier and lights stay on longer. Chicago, Houston and Dallas are uniquely positioned in the heart of North America’s most trafficked aerial corridors. This, in combination with being some of the largest cities in the U.S., make them a serious threat to the passage of migrants, regardless of season, according to Horton.

“Now that we know where and when the largest numbers of migratory birds pass heavily lit areas we can use this to help spur extra conservation efforts in these cities,” said study co-author Cecilia Nilsson.

“For example, Houston Audubon uses migration forecasts from Cornell Lab’s BirdCast program to run ‘lights out’ warnings on nights when large migratory movements are expected over the city.”

The study’s authors found that on average about half of all migrating birds pass through a city over six nights in the spring and seven in the fall. While they don’t expect cities to turn their lights off for 90 straight days, if they were willing to do it for seven nights, that could have an impact.


Lights Out efforts as well as glass remediation programs have had a positive impact in D.C. Volunteers began collaborating with the architect of the Thurgood Marshall Federal Judiciary Building in 2011. The building features a five-story glass atrium that showcases live, tall trees in the lobby. After many meetings with several people, the building’s management agreed to turn off the atrium lights during spring and fall migration.

As a result, there was a two-thirds reduction in bird-glass collisions, according to Fuisz. Lights out D.C. also worked with The Walter E. Washington Convention Center, a 2.3 million-square-foot structure, to make it less dangerous for birds. The convention center applied a Solyx bird safety window film to the outside of the overpass glass in November of 2016.

“There were only two strikes recorded at the overpass in 2017, for an 82% reduction, and zero strikes recorded at the overpass in 2018, for a 100% reduction. Since there were no other changes in the immediate environment, this means the film has been responsible for this success and is highly effective,” said Anne Lewis, president of City Wildlife.

Fuisz is encouraged by the fact that more and more communities are taking this issue seriously.

“When we started doing this 10 years ago this was not an issue that was on many people’s radar,” she said. “There are a lot more organizations like ours that have come into being. It’s really become much more central in conversations about sustainability and adaptability.”

That’s certainly the case in New York, where in May the state Senate passed the “Bird-Friendly Building Council Act,” which Friends of Animals rallied our members to support. The act would amend conservation law to create a 15-person commission within the Department of Environmental Conservation that would establish criteria to make existing buildings and new construction across the state safer for birds. The state Assembly is working on a companion bill.

In New York City alone, avian collisions kill 90,000 to 230,000 birds each year, according to NYC Audubon.

“It is so unnecessary that we continue to build in a way that endangers animal lives,” state Sen. Brad Hoylman, who sponsored the bill, told real estate blog Curb NY.

“I represent midtown Manhattan that has a number of skyscrapers sheeted in glass, and I think on any given day you can find dead birds at the base of buildings.”

State buildings in New York turn off non-essential outdoor lighting from 11 p.m. to dawn between April 15 -May 31 and Aug. 15 – Nov. 15. Other well-known structures including Rockefeller Center, the Chrysler Building and the Time Warner Center have agreed to limit lighting.


An estimated quarter-million birds die from collisions with houses and residences every year, according to Horton, so even homeowners in the most dangerous metro areas for migrating birds can play an important role.

“It’s a large-scale issue, but acting even at the very local level to reduce lighting can make a difference. While we’re hopeful that major reductions in light pollution at the city level are on the horizon, we’re excited that even small-scale actions can make a big difference,” Horton said.

While a skyscraper is going to kill more birds per year than your house or a low-rise building, they are rare among the U.S. landscapes. So, it’s important to focus on low-rise buildings as well, as they quickly accumulate bird mortality events.

“Overall it is much easier for an individual to make an immediate impact,” Horton said. “It’s harder for us to get a building manager to turn off the lights at a prominent skyscraper; that’s going to be a bigger hurdle. But someone turning the lights off at their house when they aren’t using them or pulling the blinds closed at night so the light isn’t radiating outside is an easy fix.”