how many birds are killed by buildings

Glass collisions kill vast numbers of birds in the United States each year. Yet most Americans know little about this danger, and even fewer are aware of the solutions available to help prevent these deaths — fixes that in many cases are easy and inexpensive.

To shed light on this pervasive threat, ABCs collisions experts, Christine Sheppard, Ph.D., and Bryan Lenz, Ph.D., put together a list of responses to the 15 questions they are most frequently asked. Take a look. Chances are, weve got an answer for you below.

Because glass is used so widely, giving a definitive answer is difficult, but Smithsonian researchers attempted to do so in 2014.

They estimated that homes and other buildings one to three stories tall accounted for 44 percent of all bird fatalities, about 253 million bird deaths annually. Larger, low-rise buildings four to 11 stories high caused 339 million deaths. And high-rise buildings, 11 floors and higher, kill 508,000 total birds annually. Individual skyscrapers can be quite deadly for birds, but they kill fewer birds overall due to their limited numbers.

By combining these numbers, the Smithsonian reported that collisions likely kill between 365 million and 1 billion birds annually in the United States, with a median estimate of 599 million1.

We believe that the true number is closer to a billion, or higher, for several reasons. For one, data used in the study is now more than ten years old, and there has been a steady increase in glass use since that time, increasing the likelihood of fatal collisions. In addition, weve learned that bird carcass reports tend to underestimate deaths (see questions 4 and 5), meaning that more dead birds go uncounted than we realized.

This means that the only anthropogenic (human-caused) threat that kills more birds in the United States each year is domestic cats2.

Transparent glass is invisible to both humans and birds, but humans can use door frames and other visual clues to anticipate the presence of glass and avoid collisions — most of the time. Birds, of course, dont share this ability. They perceive reflected s as literal objects, which explains why glass reflections, especially ones that present s of food, shelter, or an escape route, can trigger collisions. Learn more by visiting our “Why Birds Hit Glass” page.

After colliding with glass, some birds may be only temporarily stunned and without lasting injury — but often they are not so lucky.

In many of these cases, birds suffer internal hemorrhages, concussions, or damage to their bills, wings, eyes, or skulls3. While they may be able to fly temporarily, birds with even moderate injuries are much more vulnerable to predators and other environmental dangers.

Collisions often go unnoticed at both homes and commercial buildings for several reasons. First, many of the birds that hit windows do not die immediately and fly off without leaving a trace.

One study found that, out of 29 window collisions, only two birds died immediately and left a carcass that at the foot of the window4. However, birds can sustain severe injuries such as fractured bones and beaks, concussions, and internal bleeding3, so even birds that initially fly away likely die elsewhere.

Second, for those birds that do die and end up at the base of the building, animal scavengers often quickly remove carcasses. Cats, raccoons, birds of prey, and even squirrels, can learn to wait at windows where collisions occur for an easy meal.

Birds may also fall on inaccessible rooftops, fall through grates, end up in landscaping, or land in dense vegetation that makes them difficult to see.

Even for intensive collision monitoring programs the total number of dead birds found are always a large underestimate of the number of birds that actually collided with the glass. This is the case for reasons similar to the answer above.

Many of the birds that hit windows do not die immediately and fly off without leaving a trace. One study found that, out of 29 window collisions, only two birds died immediately and left a carcass that at the foot of the window4. However, birds can sustain severe injuries3, so even birds that initially fly away might die elsewhere.

Second, for those birds that do die and end up on the ground, animal scavengers – and people, frequently facilities teams – often remove carcasses before monitors can find them. Collision monitors even report animals, such as gulls and squirrels, learning to wait at windows where collisions occur for an easy meal. This problem is so serious that academic monitoring efforts conduct “carcass persistence studies” to estimate the number of dead birds removed before monitors walk their routes and find them5,6.

The rate at which dead and injured birds disappear can vary a lot from site to site7; researchers have found that in some places carcasses are removed within hours8 while at others it takes days5,6,7. At some locations in NYC, for example, only 25% of carcasses placed on collision monitoring routes remained when collisions monitors walked their routes later the same morning8.

Finally, for those birds that are left, monitors do not always detect all of them9. Birds may fall on inaccessible rooftops, fall through grates, end up in landscaping, land in dense vegetation that makes them difficult to see, be swept away in the gutter, or just overlooked because they blend in with the ground.

In one study where researchers accounted for both scavenging and imperfect detection, they estimated that only about 20% of birds killed were actually found by people who were searching for them9. So, it is safe to say that any number of birds picked up in a monitoring effort especially if it is not a rigorous monitoring effort, is going to be a small fraction of the birds that actually died and an even smaller fraction of the total number of birds that hit the windows.

There are many ways to making windows bird-friendly. One of the best is to use external insect screens. These screens virtually eliminate reflections, and if birds do hit them, the impact is cushioned, reducing the likelihood of injury. An added benefit is that these screens are easy to install on existing or new home windows.

If screens arent an option, you can use a range of materials — tape, decals, strings, cords, paint, netting, and shutters are options — to create window patterns that birds will interpret as solid objects, needing to be avoided. Check out our great home-friendly solutions guide here.

Its important to make sure that birds see no viable way to fly between the markers or objects youre using, so make sure to eliminate all spaces larger than two inches.

Remember, whichever material you use needs to be visible to birds from at least ten feet away so that they have time to see the material and change course.

The best place to apply solutions is on the outside of the window, where they are easily visible.

However, using external solutions isnt always an option. Some windows — like those on tall buildings — can be difficult to access from the outside.

In these cases, we recommend testing a variety of solutions. This is because different kinds of glass have varying reflective levels and, unfortunately, there is no universal solution.

To conduct a test, apply a sticky note, tape, or sample of your proposed solution to the inside of the window and then look at it from the outside every hour or two, starting in the early morning.

If you can see your test material most of the time, birds will too, and an inside solution may work for you.

In many cases, however, internal solutions do not work, and reflections will hide your solution during part or all of the day, thereby reducing or eliminating its effectiveness.

But this shouldnt deter you from acting. is better than doing nothing. Adding something to your windows is better than doing nothing.

There are effective solutions that cover as little as 1% of the window area, allowing sunlight in and a view out. In our experience, people quickly adjust to bird-friendly design solutions, often forgetting that they are even there. We have also found that when family, friends, or customers notice the pattern and learn its purpose, they appreciate the effort to protect birds.

If youre looking to retrofit existing windows, there is a wide range of solutions from which to select, depending upon personal preferences.

If you are designing a new building or replacing windows, consider the professional solutions favored by architects. Many of these elegant products have enjoyed long-standing popularity among architects for their aesthetic appeal alone. For more on designing a new building or replacing windows, visit the “Resources for Architects, Planners, and Developers” page. Looking for inspiration? Check out our bird-friendly building gallery.

Light can increase collision numbers in several ways. Recent studies confirm that urban glow attracts birds into the human-built environment10,11, where they run a higher risk of collisions.

Migratory birds traveling at night are also attracted by intense lights contrasted against the night sky. The “beacon effect,” as this occurrence is commonly known, can be caused by lighthouses, offshore oil platforms, or powerful light displays, like the twin beams at the 9/11 Tribute in Lights memorial in New York City. These lights can thoroughly disrupt birds ability to navigate, pulling them off course and effectively trapping them around the light12 or disorienting them. At the 9/11 memorial, volunteers monitor the birds and the lights are turned off when needed to allow safe passage.

Brightly lit building facades can also affect birds. In some cases, these facades and brightly lit windows can cause collisions at night13,14. These birds are seen fluttering at lit windows or exhausted on the ground14 where they are vulnerable to predators.

Despite the dangers posed by nighttime lights, its important to note that most collisions take place during the day. These collisions are due to habitat reflected in or seen through glass, and they are often direct and deadly.

While turning off lights is a great way to help birds and other wildlife, the best way to prevent collisions, especially at homes, is to use one of the many options available to treat your windows.

A single decal may be enough to warn an alert human to expect a glass door, but for a bird its simply an obstacle to fly around.

To successfully deter birds, decals and other collision deterrents must be applied with proper spacing to create the illusion of a cluttered environment through which it would be difficult or impossible to fly. You can learn more here. Remember to make sure that whichever pattern you use on your windows should not have any spaces more than two inches wide.

The first thing to do is document the problem. Take photos of the dead birds you find and keep a list of numbers and dates.

If there is a facilities or maintenance department, ask what they have noticed; they are usually responsible for cleaning up birds that have died after hitting glass and may be great allies who help you collect data or convince building managers of the danger to birds.

After documenting the problem, review the window solutions on ABCs site, contact the building owner or manager to tell her or him about the problem, and provide advice or resources (such as this blog) on how to address it.

Keep in mind that you are making a request and looking for a partner to save birds, so be sure to keep these interactions positive and non-confrontational. Avoid vilifying the responsible party for a collision problem that they likely had no idea existed.

You can also talk to people who live, work, or shop in the building in question to see if anyone else shares your concerns. If so, ask them if they would like to be involved. By working with others, you build a collective voice that can draw more attention to the problem.

Remember, there are many ways to get involved. These include helping with monitoring, writing letters to building owners, attending meetings with building management, and organizing community action.

A variety of factors determine the level of the threat they pose, including the amount of glass used, placement and reflectivity of the glass, the height and extent of vegetation around the building, and the presence of water, among other things.

Given incremental cost of constructing a bird-friendly building, we believe that all new buildings — not just glass-covered skyscrapers — should incorporate bird-friendly features. It is less expensive to incorporate these features from the beginning of the planning process, compared to retrofitting a building later.

There are several ways to help make this happen. The first is to develop and pass a local ordinance requiring the adoption of bird-friendly building standards in your community. To download an easy-to-use ordinance template, click here. You can also take a look at our list of existing ordinances mandating bird-friendly design or creating voluntary standards.

Keep in mind that ordinances tend to apply to large buildings and exempt low rises and homes, so it is important to make sure that the ordinance applies to as many buildings as possible.

Although passing an ordinance is a great accomplishment, its not the only thing you can do.

Consider approaching the developers of new and proposed building projects with your concerns. Since this can be a time-consuming process, we suggest focusing on projects with a high likelihood of success (e.g., nature centers, museums) or organizations that influence multiple buildings (e.g., local government, universities, health care organizations, and architecture firms) to help them adopt bird-safe building policies.

While its critical to make sure that new buildings incorporate bird-friendly designs, dont forget that existing buildings already account for hundreds of millions of bird deaths annually. Consequently, the need to retrofit homes and other buildings will remain an important way to reduce bird collisions for the foreseeable future.

Not necessarily. When architects, developers, and other stakeholders intend to create a LEED-rated building, they review available credit options and select the amount of credits needed for the rating they want.

Bird-friendly credits, however, werent available until 2011, when the LEED program adopted a new, bird-focused building design credit known as “Pilot credit SSpc55: Bird Collision Deterrence.” LEED added a permanent “Bird Collision Deterrence” credit to the Innovation Catalogue in 2022.

Like all credits in the LEED system, the use of this bird-friendly credit is not mandatory. So, while many builders have opted to use this credit, not all LEED-rated buildings are bird-friendly.

Regardless of LEED rating, we strongly encourage architects and builders to incorporate bird-friendly buildings guidelines into their designs. To find out more about testing and LEED ratings, visit our LEED Innovation Credit page.

Collisions dont happen at an even pace over the course of a year, or even throughout the day.

Most collisions happen during daylight hours or immediately before dawn, with some occurring at night. Mornings, in particular, tend to be the worst time of day for collisions15,16,17, 18. During migration, this is because migratory birds that have flown all night stop to look for a place to land and refuel. Those that land in and near cities find themselves in a maze of deadly glass. In addition, resident birds are generally most active in the morning, as they wake up hungry and immediately search for food.

During the course of a year, migration periods often bring the largest upticks in collisions, when huge numbers of birds stop to rest, often in unfamiliar areas where glass is common10,19,20. Many collisions programs are focused collisions during migration in cities where they tend to occur in large numbers. Migrant mortality in fall tends to be worse than spring due to the larger number of birds in flight. This is because fall migration includes both adult birds and juveniles that were born over the summer. Spring migration includes only adults returning to breed.

But migration is not the only dangerous season. We also see collision increases in late spring18, as nesting birds fledge their young, and in winter21,22, when resident birds leave their territories and cover larger areas in search of food. In the winter, bird feeders near windows can be a cause of mortality from collisions23.

American Bird Conservancy strives to reduce bird-and-glass collisions by making the human-built environment as safe as possible for birds. To maximize our impact, we focus on the following areas:

Product testing: We operate a flight tunnel to better understand how birds interact with various commercially available window treatments (watch our video to learn more). These evaluations help us create bird-friendly building guidelines for architects and recommend effective solutions for people living in homes and other buildings. As experts in the field, we also evaluate and document scientific literature related to bird collisions.

Legislation, codes, and LEED: We help promote science-based, bird-friendly legislation based on the results of tunnel tests conducted by ourselves and other researchers. For example, we worked with members of Congress to draft the national Bird-Safe Buildings Act, which would require public buildings to incorporate bird-friendly building design and materials. We have also helped to establish building guidelines like the LEED Bird Collision Deterrence Innovation Credit and pass local ordinances. Check out the Bird-friendly Legislation tab on our Legislation page for more details.

Educating architects and engineers: ABC offers a bird-friendly building design course that architects can take for continuing education credit from the American Institute of Architects and the Green Building Council.

Guidance on retrofits and monitoring: ABC helps businesses, universities, and individuals create effective monitoring programs and select the right solutions to reduce collisions. Public education and outreach: A large part of ABCs collisions mission is raising public awareness about this issue. We connect people with solutions and provide detailed information to homeowners, architects, engineers, and lawmakers.

New initiatives: We are always working to improve bird-friendly window products while encouraging public action to reduce bird mortality rates. To keep up with our collisions program, you can sign up to receive email updates, or follow us on Facebook or X (formerly Twitter).

Dr. Christine Sheppard is ABCs Bird Collisions Campaign Director. She earned her Ph.D. at Cornell University and worked as head of the Bronx Zoos Ornithology Department before joining ABC. Since then, she has authored both editions of the ABC publication Bird-friendly Building Design. She created AIA/LEED continuing education classes on Bird-friendly Design, helped design San Franciscos Standards for Bird-safe Buildings, and has been involved in writing code and legislation in many different locations. Sheppard helped develop the USGBC LEED Pilot Credit 55: Reducing Bird Mortality. She was named an Engineering News-Record “Top 25 Newsmaker for 2014” because of her work on glass testing, and has worked with most major glass manufacturers on design and evaluation of bird-friendly materials.

Dr. Bryan Lenz is ABCs Bird Collisions Campaign Manager. He earned his Ph.D. at Tulane University and worked as the Director of the Community Conservation program at Bird City Wisconsin, and as the Chief Scientist at the Western Great Lakes Bird & Bat Observatory. At ABC, Bryan works to reduce the collision threat that the built environment, especially glass, poses to birds. His work incorporates research, design, legislation, building codes, education, outreach, and marketing.

Naturally, David Willard has dedicated nearly his entire life to addressing this problem. He arrived at McCormick Place early on a recent Thursday and started to walk around the three-story structure. He moved swiftly, peering into the shadows and searching the concrete for tiny feather clumps.

“I suppose I’m hopeful,” he remarked, the birds nestled inside a backpack he carried on his shoulder. However, I detest the fact that it takes 900 birds in a single night to attract attention. ”.

Two factors contribute to the issue of bird collisions: glass and lights. Bright lights are known to both confuse and attract migratory birds, who fly primarily at night, according to scientists. Dawn reflections in windows depicting the sky and trees entice birds to perish. In certain circumstances, glass becomes invisible to birds, causing them to strike it while aiming for areas beyond It affects not only well-lit downtown areas but also structures outside of urban areas, such as homes in rural and suburban areas. Although lights can attract and confuse birds at any height, the majority of collisions occur on the lowest floors. Yes, the majority of bird deaths occur in low-rise commercial areas and residential neighborhoods rather than on the top floors of skyscrapers.

Two years ago, the long-term monitoring of McCormick Place led to a finding whose importance rivaled Klem’s work in southern Illinois in the 1970s. Convention business had slowed around 2000, and the number of dark days at McCormick Place’s Lakeside Center had increased. This allowed Willard and his colleagues at the Field Museum to compare the number of bird collisions when the building was dark to the number of collisions when it was lit. They kept track of this for two decades. In 2021, they reported that dimming the lights had reduced bird collisions by 60 percent. It was clear proof, at least on the scale of a single building, that turning off the lights could work.

Up until now, most bird-friendly glass has been optional and has only been utilized on public structures like the Jacob Javits Convention Center in New York City or at academic institutions like the Gang-designed dorm towers at the University of Chicago. But more and more towns and even smaller ones are passing laws requiring these characteristics.

Your contribution will be matched dollar-for-dollar. Act by December 31!

Every year in the United States, a great number of birds are killed by glass collisions. However, the majority of Americans are unaware of this risk, and even fewer are aware of the easy and affordable fixes that can be used to help stop these deaths.

In order to clarify this ubiquitous danger, ABC’s collision specialists, Christine Sheppard, Ph. D. , and Bryan Lenz, Ph. D. assemble a list of answers to the top 15 questions they get asked. Take a look. Chances are, weve got an answer for you below.

Although it is challenging to provide a conclusive response due to the widespread use of glass, Smithsonian researchers made an effort in 2014.

They calculated that dwellings and other structures with one to three stories were responsible for approximately 253 million bird deaths a year, or 44% of all bird fatalities. Larger, lower-rise structures with four to eleven stories contributed to 339 million deaths. And each year, 508,000 birds are killed by high-rise buildings with eleven stories or more. Because there are fewer skyscrapers overall, fewer birds are killed by them even though individual skyscrapers can be quite lethal.

Combining these figures, the Smithsonian concluded that, with a median estimate of 599 million, collisions probably kill between 365 million and 1 billion birds yearly in the United States.

For a number of reasons, we think the actual figure is closer to one billion or even higher. One reason is that the study’s data was collected more than ten years ago, and since then, glass use has steadily increased, raising the risk of deadly collisions. Furthermore, we now know that reports of bird carcasses frequently understate the number of deaths (refer to questions 4 and 5). This implies that a greater number of dead birds remain uncounted than previously believed.

This indicates that domestic cats are the only anthropogenic (caused by humans) threat that kills more birds in the United States annually2.

Both humans and birds cannot see transparent glass, but most of the time, humans can anticipate the presence of glass and avoid collisions by using visual cues such as door frames. Birds, of course, dont share this ability. Because they interpret reflections as actual objects, they can cause collisions when they present glass reflections, particularly when they represent food, shelter, or an escape route. Learn more by visiting our “Why Birds Hit Glass” page.

Some birds may be lucky enough to be momentarily stunned and escape permanent injury after colliding with glass, but this is not always the case.

Birds sustain internal bleeding, concussions, or harm to their bills, wings, eyes, or skulls in many of these incidents3. Birds with even minor injuries are far more susceptible to predators and other environmental threats, even though they might be able to fly for a short while.

However, in many cases, birds are killed right away and never escape.

For a variety of reasons, collisions at residential and commercial buildings frequently go unreported. First off, a lot of birds that strike windows do not always die instantly and depart without leaving a trace.

According to one study, only two of the 29 birds that collided with windows died right away, leaving a carcass at the base of the window4. However, even birds that initially fly away most likely die somewhere else due to severe injuries like fractured bones and beaks, concussions, and internal bleeding3.

Second, animal scavengers frequently remove bird carcasses from the base of buildings quickly when they do die. For a simple meal, cats, raccoons, raptors, and even squirrels can learn to wait at windows where collisions happen.

In addition, birds can tumble through grates, land in landscaping, fall onto inaccessible rooftops, or land in dense vegetation that obscures their view.

The total number of dead birds discovered is consistently much lower than the actual number of birds that collided with the glass, even in the case of extensive collision monitoring programs. This is the case for similar reasons to the response given above.

A large number of birds that strike windows do not instantly perish and depart without leaving any evidence behind. According to one study, only two of the 29 birds that collided with windows died right away, leaving a carcass at the base of the window. But birds can get serious injuries3, so even if they take off at first, they might end up dead somewhere else.

Second, when birds do pass away and land on the ground, the carcasses are usually removed by animal scavengers and humans—often facilities teams—before monitors can discover them. Collision monitors even report that animals, like squirrels and gulls, have learned to wait at windows where collisions happen in order to have a quick meal. Because of the severity of this issue, academic monitoring programs carry out “carcass persistence studies” to determine how many dead birds are removed before monitors walk their routes and discover them5,6,

Researchers have discovered that the rate at which injured and dead birds vanish varies greatly from site to site7; in some instances, carcasses are removed in a matter of hours8, while in others, it takes days5,6, 7. At certain locations in New York City, for instance, only 25% of the carcasses placed on collision monitoring routes remained after the collisions and the monitors walked their routes later that same morning.

Lastly, not all of the remaining birds are always picked up by monitors9. Birds can fall through grates, onto inaccessible rooftops, into landscaping, into thick vegetation that obscures their view, get swept away in gutters, or simply go unnoticed because they blend in with the surroundings.

In one study where the researchers took into account both scavenging and imperfect detection, they calculated that only roughly 2020% of the killed birds were actually found by people who were looking for them. Therefore, it is safe to conclude that the number of birds detected during a monitoring effort, particularly if it is not thorough, will be a small portion of the birds that truly perished and a much smaller portion of the total number of birds that struck the windows.

There are many ways to making windows bird-friendly. One of the best is to use external insect screens. These screens almost completely block reflections, and in the unlikely event that birds do strike them, the impact is softened, minimizing damage. Easy installation of these screens on new or old home windows is an additional advantage.

If screens aren’t an option, you can make window patterns that birds will perceive as solid objects that need to be avoided using a variety of materials, including tape, decals, strings, cords, paint, netting, and shutters. Check out our great home-friendly solutions guide here.

Make sure to remove any gaps larger than two inches so that birds cannot see a feasible path between the markers or objects you are using.

Always keep in mind that the material you choose must be visible to birds from a minimum of ten feet away, giving them enough time to notice it and alter their course.

Applying solutions outside the window, where they are readily visible, is the best option.

However, using external solutions isnt always an option. Certain windows, such as those found in tall buildings, can be challenging to reach from the outside.

In these cases, we recommend testing a variety of solutions. This is due to the fact that different types of glass have differing degrees of reflection, and sadly, there isn’t a universal fix.

Apply a sticky note, piece of tape, or a sample of your suggested solution to the inside of the window and observe it from the outside every hour or two, beginning in the early morning, to conduct a test.

Birds will see your test material if you can see it most of the time, so you might be able to solve the problem internally.

However, internal solutions frequently fail, and reflections will obscure your solution for some or all of the day, diminishing or eliminating its efficacy.

But this shouldnt deter you from acting. is better than doing nothing. Adding something to your windows is better than doing nothing.

No, you can save birds without sacrificing your vision.

There exist efficacious solutions that occupy as little as 1% of the window area, permitting sunlight to enter and a gaze out. According to our observations, people get used to bird-friendly design solutions quickly and frequently forget they are there. Additionally, we’ve discovered that when loved ones, acquaintances, or clients see the pattern and understand its significance, they value the efforts made to preserve birds.

Depending on your preferences, there are several options available if you’re looking to retrofit existing windows.

When planning a new construction or replacing windows, take into account the expert solutions that architects recommend. Architects have long favored many of these sophisticated products purely for their visual appeal. To learn more about window replacement or building design, go to the “Architects, Planners, and Developers” page. Looking for inspiration? Check out our bird-friendly building gallery.

Light can increase collision numbers in several ways. According to recent studies, birds are drawn to the human-built environment by urban glow, increasing the likelihood of collisions10,11.

Strong lights set against the night sky also draw migratory birds that are flying at night. The phenomenon referred to as the “beacon effect” can be attributed to various factors such as lighthouses, offshore oil platforms, or intense light displays, such as the twin beams at the 9/11 Tribute in Lights memorial located in New York City. These lights have the potential to seriously impair birds’ ability to navigate, causing them to veer off course and become trapped near the light12 or confused. Volunteers at the 9/11 memorial keep an eye on the birds, and when necessary, they turn out the lights to ensure everyone can pass safely.

Brightly lit building facades can also affect birds. These facades and their vivid windows may occasionally result in nighttime collisions13, 14. These birds can be observed flapping at windows that are lit or worn out on the ground, where they are more susceptible to predators.

Even though nighttime lights can be dangerous, it’s crucial to remember that most collisions happen during the day. These collisions, which are frequently fatal and direct, are caused by habitat reflections in or seen through glass.

While turning off lights is a great way to support birds and other wildlife, treating your windows with one of the many available options is the best way to prevent collisions, especially at homes.

For a bird, a glass door is just another obstacle to fly around, but a single decal might be sufficient to alert a vigilant human to its presence.

Decals and other collision deterrents must be placed with appropriate spacing to give the impression of a cluttered environment through which it would be difficult or impossible for birds to fly in order to effectively deter birds. You can learn more here. It’s important to keep in mind that no pattern you choose for your windows should have any gaps wider than two inches.

The first thing to do is document the problem. When you come across dead birds, take pictures of them and record the numbers and dates.

Ask the facilities or maintenance department what they have observed; they are typically in charge of cleaning up dead birds that have struck glass, and they could be valuable allies in helping you gather information or persuade building managers of the threat to birds.

Once the issue has been documented, go over the window solutions on ABC’s website, get in touch with the building manager or owner to inform them of the problem, and offer guidance or resources (like this blog) on how to resolve it.

Remember that you are asking for help and seeking a partner in order to save birds, so make sure that these exchanges are constructive and non-aggressive. Refrain from demonizing the person in charge of a collision issue that they probably were unaware of.

You can also find out if anyone else is concerned about the same things by speaking with residents, employees, or shoppers in the disputed building. If so, inquire as to whether they would like to participate. Collaborating with others creates a collective voice that can raise the issue’s profile.

Remember, there are many ways to get involved. These consist of lending a hand with monitoring, composing correspondence for building owners, participating in building management meetings, and planning community outreach.

Visit our “How to Advocate for Retrofits” page for additional advice.

Structures not built with bird-friendly design principles run the risk of becoming lethal to birds.

The amount of glass used, where it is placed, how reflective it is, how tall and how much vegetation surrounds the building, and whether or not there is water are some of the variables that affect how dangerous they are.

We feel that all new construction, not just glass-covered skyscrapers, should include bird-friendly features due to the increased cost of creating a bird-friendly building. When considering these features at the outset of the planning process, the cost is lower than when retrofitting an existing building.

There are several ways to help make this happen. The first step is to create and approve a local ordinance mandating that your community adopt bird-friendly building standards. To download an easy-to-use ordinance template, click here. You can also review our list of current ordinances that require bird-friendly design or establish voluntary guidelines.

Remember that most ordinances only apply to large buildings, leaving out homes and low-rises, so it’s critical to ensure that the ordinance covers the greatest number of buildings.

While enacting an ordinance is a fantastic achievement, there are other things you can do.

Think about voicing your concerns to the developers of both proposed and ongoing construction projects. We advise concentrating on projects with a high chance of success because this can be a time-consuming process (e g. , museums, nature centers) or establishments that have an impact on several structures (e g. , local government, academic institutions, healthcare facilities, and architectural firms) to assist them in implementing building regulations that protect birds.

Though it’s important to ensure that new construction has bird-friendly designs, keep in mind that hundreds of millions of birds already perish each year due to existing buildings. Thus, for the foreseeable future, retrofitting homes and other buildings will be necessary to reduce bird collisions.

To learn more visit our “Creating Bird-Friendly Legislation” page.

Not necessarily. When architects, developers, and other stakeholders intend to create a LEED-rated building, they review available credit options and select the amount of credits needed for the rating they want.

Bird-friendly credits, however, werent available until 2011, when the LEED program adopted a new, bird-focused building design credit known as “Pilot credit SSpc55: Bird Collision Deterrence.” LEED added a permanent “Bird Collision Deterrence” credit to the Innovation Catalogue in 2022.

Utilizing this bird-friendly credit is optional, just like with all other credits in the LEED system. Thus, not all LEED-rated buildings are bird-friendly, even though many builders have chosen to use this credit.

We strongly advise architects and builders to incorporate bird-friendly building guidelines into their designs, regardless of their LEED rating. Check out our LEED Innovation Credit page for additional information regarding testing and LEED ratings.

No two collisions occur at the same rate over a year or even a single day.

The majority of collisions occur during the day or right before dawn, though some do happen at night. Particularly in the mornings, collisions tend to occur more frequently during the day15,16,17, and 18. This occurs during migration when migratory birds stop to look for a place to land and refuel after flying all night. People who land in or close to cities discover themselves in a deadly glass maze. Furthermore, local birds are usually busiest in the morning when they wake up hungry and start looking for food.

Over the course of a year, migration periods frequently result in the highest increases in collisions as large numbers of birds pause to rest, frequently in uncharted territory where glass is prevalent10,19,20. Numerous collision programs concentrate on collisions that happen during migration in urban areas where they typically happen in large numbers. Fall typically sees higher migrant mortality than spring because there are more birds in the air during that season. This is due to the fact that fall migration consists of both mature and summer-born juvenile birds. Spring migration includes only adults returning to breed.

But migration is not the only dangerous season. Moreover, we observe an increase in collisions in the late spring (18) when nesting birds fledge their young, and in the winter (21, 22), when resident birds abandon their territories and travel farther in pursuit of food. Bird feeders near windows can result in collision deaths during the winter23.

The American Bird Conservancy works to minimize bird-glass collisions by creating an environment where human construction has left birds as safe as possible. To maximize our impact, we focus on the following areas:

Product testing: To better understand how birds interact with different commercially available window treatments, we run a flight tunnel (watch our video to learn more) These assessments enable us to develop guidelines for architects designing bird-friendly buildings and suggest practical fixes for occupants of houses and other structures. We assess and record scientific literature about bird collisions as subject matter experts.

Codes, laws, and LEED: We support the development of science-based, bird-friendly codes based on our own and other researchers’ tunnel test results. For instance, we collaborated with Congressmen to draft the national Bird-Safe Buildings Act, which mandates the use of bird-friendly building materials and designs in public buildings. Additionally, we have assisted in passing local ordinances and establishing building guidelines such as the LEED Bird Collision Deterrence Innovation Credit. For more information, visit our Legislation page and look under the Bird-friendly Legislation tab.

Teaching engineers and architects: The American Institute of Architects and the Green Building Council both offer continuing education credits to architects who complete ABC’s bird-friendly building design course.

Advice on retrofits and monitoring: ABC assists companies, academic institutions, and private citizens in developing efficient monitoring systems and choosing the best ways to lower the number of collisions. Public outreach and education: Increasing public awareness of this issue is a major component of ABC’s collisions mission. We link people to solutions and give legislators, architects, engineers, and homeowners comprehensive information.

New projects: We are constantly striving to enhance window goods that are friendly to birds while promoting public action to lower bird mortality rates. You can follow us on Facebook or X (formerly Twitter) or sign up to receive email updates about our collisions program.

Dr. Christine Sheppard is ABCs Bird Collisions Campaign Director. She earned her Ph. D. before joining ABC, he was employed at Cornell University as the head of the ornithology department at the Bronx Zoo. Since then, she has written the books for Bird-friendly Building Design in both of its editions published by ABC. She developed AIA/LEED continuing education courses on bird-friendly design, contributed to the creation of San Francisco’s standards for bird-safe buildings, and has written laws and codes in numerous jurisdictions. Sheppard was involved in creating LEED Pilot Credit 55: Reducing Bird Mortality for the USGBC. Because of her work on glass testing, she was named one of Engineering News-Record’s “Top 25 Newsmakers for 2014.” She has collaborated with most major glass manufacturers on the design and assessment of materials that are friendly to birds.

Dr. Bryan Lenz is ABCs Bird Collisions Campaign Manager. He earned his Ph. D. at Tulane University and held positions as Chief Scientist at the Western Great Lakes Bird Observatory and Director of the Community Conservation Program in Bird City, Wisconsin. Bryan works at ABC to lessen the risk of bird collisions caused by the built environment, particularly by glass. Research, design, law, building codes, outreach, education, and marketing are all incorporated into his work.

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• Samuels B, Fenton B, Fernández-Juricic E, & MacDougall-Shackleton SA. 2022. Viewing the “black box” of bird-window collisions: passively captured home backyard videos PeerJ 10:e14604 https://doi. org/10. 7717/peerj. 14604.
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