Lights Out programs prevent over 200,000 bird-window collisions annually

birds_collision coverBy Orion McCarthy 


Everyone knows the sickening sound created when an unsuspecting bird crashes into a window. The sound signifies an abrupt demise,  a chance encounter with an invisible and immovable object.  Without even looking outside, you know the damage is done.  All that’s left is a ball of feathers.

bird collision thumbnail

Conservation volunteers in Baltimore regularly find birds killed by window strikes that are species of greatest conservation need.  Photo credit: Wild About Nature Blog.

For birds, the invisible, reflective, and unforgiving glass omnipresent in our homes and office buildings poses a very real threat. An estimated 365 to 988 million birds die each year from window collisions in the United States alone. That’s anywhere from 2 to 10 percent of the country’s entire bird population.

Fortunately, over the past two decades, more and more cities have taken action to prevent bird deaths from window strikes. Boston, New York, Minneapolis, Detroit, Houston, Baltimore, San Francisco and Washington DC have joined pioneers such as Toronto and Chicago to prevent unnecessary bird deaths.

In many cases, the solution is as simple as turning off the lights.

City lights can easily disorient or distract birds, which are drawn to them like moths to a flame. Birds often become trapped in columns of light, flying in circles until they become exhausted or crash into reflective windows.

Migrating songbirds are disproportionately affected by window strikes because they travel at night. Flying in the dark helps these tiny birds avoid predators, strong winds, and the midday heat.

While birds evolved to navigate by the light of the stars, well-lit urban areas increasingly dot the paths of migratory species. One study found that birds have a 70% chance of encountering an urban environment such as a city or suburb on their journey from the Gulf of Mexico to Canada.


Certain bird species are more prone to window strikes than others. The most heavily affected species are migratory birds that winter in the tropics, known as Neotropical migrants. These window strike victims were found by volunteers with Baltimore’s Lights Out program. The species are, from left to right, an American woodcock, a black-eyed junco, a yellow-bellied sapsucker, an ovenbird, a catbird, and a northern flicker. Photo credit: The Washington Post.

Lights Out programs seek to reduce the risks faced by migratory birds passing through cities.

Toronto became the first major city to establish a Lights Out program after the establishment of the non-profit FLAP (The Fatal Light Awareness Program) in the early 1990s. FLAP’s dedicated volunteers began collecting birds killed by window collisions around the city, tracking the data to pinpoint hotspots and problematic buildings.

Armed with their data, FLAP approached building managers to make their case for a bird friendly city. They argued that switching off or dimming lights between midnight and dawn in times of heavy migration would save building managers money and cultivate an image of environmental friendliness for their buildings. And of course, it would save many thousands of birds.

It was a clear win-win, and building managers began shutting off their lights.

Word began to spread around the city, and now over 100 buildings in downtown Toronto participate.

toronto lights out program

Toronto’s skyline is shown above, both with lights at normal levels (top) and during times of heavy bird migration when lights are dimmed (bottom). In addition to saving birds, Lights Out programs save building managers an average of $6,000 per year on utilities.  Photo credit: WWF Canada.

Following Toronto’s success, other cities have started their own Lights Out programs. In 1999, Chicago became the first major city in the United States to shut off their lights during the spring and fall months. New York City followed suit in 2005 with a voluntary Lights Out program aimed at both tall and riverfront buildings, including iconic skyscrapers such as the Chrysler Building and Rockefeller Center.

Studies of bird collisions in Toronto, Chicago, and New York found that the average high-rise is responsible for 700 to 1,000 bird deaths a year. Inclement weather can significantly increase this total.

Researchers also found that dimming the lights of these high-rises during the migratory season reduced bird mortality by an average of 83%.

With roughly 300 buildings in Toronto, Chicago, and New York participating in Lights Out programs, that adds up to as many as 200,000 prevented bird deaths. And that’s just for those three cities.

To date, over 20 cities in the United States and Canada have a Lights Out Program. In addition, cities in 178 countries turn off their lights each year for Earth Hour, an initiative organized by the World Wildlife Fund to raise awareness about energy consumption, light pollution, and climate change.

By reducing energy consumption, Lights Out programs reduce greenhouse gas emissions and could become an instrumental tool for cities looking to cut emissions to hit climate mitigation targets.

As other cities start to turn out their lights, Toronto and Chicago have continued to innovate, developing even more programs to protect migratory birds. Toronto has created a list of Bird-friendly Development Guidelines and started the Bird Flyways Project to enhance existing green space around the city for migratory birds. Chicago has also worked to improve bird habitat through green roofs and bird sanctuaries, and has an extensive public awareness campaign to engage citizens about the challenges migratory birds face on their epic journey.

What YOU can do

By focusing on skyscrapers and high-rises, Lights Out programs address the most concentrated source of bird collision fatalities. But shutting the lights off in only the tallest buildings doesn’t address the true scope of the problem.

bird window reflection Steven Scott

Windows can be dangerously deceptive to birds. Homes and low-rise office buildings account for more bird deaths then skyscrapers. Photo credit: Steven Scott.

Given the relatively small number of skyscrapers and high-rises, these buildings account for only 1% of bird collision fatalities. Low-rise buildings account for 56% of fatalities, while collisions with 1 to 3 story homes account for 44% of all bird deaths.

This means that broader public engagement is needed to significantly reduce migratory bird collisions. It means that you have a role to play.

Fortunately, by following these few simple steps you can prevent the unnecessary deaths of migratory birds around your home.

Participate in Lights Out – Dim or turn off lights near windows or in rooms that no one is using after dark, and extinguish exterior lights that are directed upwards. Take these steps during the migratory season, which extends from mid March to June in the spring and from September to November in the fall, or use the migratory forecasting tool developed by FLAP to receive alerts during times of heavy migration. In addition to saving birds, shuttering unnecessary lights will reduce your carbon footprint and save you money on utilities.

bird feeder window strikes

Placing bird feeders close to windows (1 to 2 ft) to reduce bird strikes may seem counterintuitive, but it ensures that any birds that do collide with the glass won’t have enough momentum to injure themselves. Photo credit: Wikipedia.

Make your windows bird safe – Move potted plants away from windows, as the foliage attracts birds looking for a place to land and rest, and use screens, drapes, and blinds to reduce window reflectivity. If you have a bird feeder, move it within 2 feet of your house or further than 30 feet. Finally, if you notice some windows are particularly prone to bird strikes, attach decals, string, or netting on the outside of those windows to deter birds. Collidescape (a one-way window coating) and WindowAlert (ultraviolet window decals that are highly visible to birds) are two good products for increasing window visibility, but there are many other products as well depending on your need or preference. 

Keep cats indoors – While they make cute and cuddly pets, cats are technically an invasive predatory species and are a major cause of biodiversity loss in urban areas. Domestic and feral cats are responsible for an estimated 2.4 billion bird deaths annually, surpassing even window strikes as a leading cause of bird mortality. By spaying or neutering your cat and keeping it indoors, especially during migration seasons, you reduce the risk faced by songbirds as they make their long journey across the continent.

Get Involved – Do you feel strongly about protecting songbirds? Are you a bird enthusiast? Lights Out initiatives across the country need volunteers to help monitor bird mortality to gauge the effectiveness of Lights Out programs. By pitching in, you become part of a vibrant and dedicated birding community, contribute to conservation research, and learn valuable information about local wildlife. You can also help by taking part in FLAP Mapper, a citizen science project for mapping bird collision fatalities. If you spot a dead bird near a window, input the location where you found the bird, the species, and the date online, and the data will be used to help scientists better understand the patterns of bird-window collisions.

bird death from window strike
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  1. Brenda · · Reply

    Toronto and Baltimore have something else in common great MLB. teams having threatened song birds as their brand. Orioles and Blue Jays.

    As fall migration and the AL east rivalry heats up lets try to get the ballclubs to show a rapid college of song bird’s with the message like”you’ve loved your Orioles – Jays all season help them go all the way! Help them get home.
    Cause once they are gone they are gone!

    Face it with crowded stadiums right on the migration route it would be a good way to get the conversation started. (close your. curtains dim your lights during migration season.

    I mentioned this to FLAP in Toronto last year but I think both cities have to get together to pitch this and either hope the clubs would do it as a public service.
    I think it would be unheard of to have the 2 teams pulling together. (Maybe next year the Cardinals could be involved.)
    I bet the player’s wives could get management to listen.So if anyone at your end has an in or influence with the Orioles’ organization…..



    1. That is a fantastic idea! The Baltimore Oriole, blue jays, and cardinals could certainly serve as flagship species for song birds in general to raise awareness about light pollution. And at a stadium no less, where glaring lights can offer such a stark example of the dangers of light pollution. I unfortunately don’t know anyone with the Orioles affiliation, but passing this idea along to the Baltimore Lights Out chapter could probably get the ball rolling


  2. […] to deter birds. You can also help by turning off unnecessary lights during the spring and fall. Light pollution can easily disorient or distract birds, especially during their migration, making them more likely […]


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