Window Woes and Traveling Birds

Migrating Birds Need Our Help

U.S. Fish and Wildlife Service
6 min readMar 20, 2018

By Gretchen Nareff, U.S. Fish and Wildlife Service

Imprint of a bird in building window by Pedro Ramirez, Jr. / USFWS

Each spring and fall, migratory birds begin their journey north. Many spend their winters in South and Central America, doing whatever it takes to survive so they can reach their breeding grounds in North America and successfully produce young. But what happens to these birds in between? It is a treacherous and arduous journey. Some die in storms or get off course and are lost over the Gulf of Mexico. Others die from exhaustion or starvation. As challenging as it is to navigate these hazards, the very buildings that we that we erect can add to the dangers they face.

Find a Stunned Bird?

Follow this advice.

Photos used with permission by Melissa Marshall

Why Did That Bird Hit My Window?

The short answer: Reflection.

Bird collisions with buildings are an all-too-common occurrence. Birds don’t perceive glass the same way humans do and they don’t recognize it as a barrier. During the day, while they are flying around to forage, the reflection of the sky and vegetation on windows actually deceives birds into flying into them. This can happen on any structure with glass: your home, a bus shelter, a single-story business, or a skyscraper.

Reflections on buildings can be indistinguishable from the sky. Photo by Chris Deets/USFWS

At night while birds are migrating, tall buildings may not be detectable, especially during bad weather. Conversely, buildings that remain lit at night may actually attract birds like moths to a flame. These birds will either collide with the buildings, or, in the case of projected light, get trapped by the illumination and flutter around it for hours, exhausting themselves.

And Now the Personal Story and the Harsh Reality

Imagine walking into your two-story office building in the morning and seeing bright blue, yellow, or orange bodies scattered in front of the shrubbery. That happened to me for a few weeks during the peak of spring migration last year. I frequently found dead Indigo Buntings, Nashville and Tennessee Warblers, hummingbirds, and Baltimore Orioles. As a wildlife biologist whose primary job is conservation of birds, it is devastating to work in a building that kills migratory songbirds.

A coworker watched helplessly as a female Rose-breasted Grosbeak flew from a bush into the window and died almost instantly. I walked outside of the building one morning and found a live Sora, confused and visibly stressed, trying to escape its pavement and concrete surroundings. It would have to spend the day in a vulnerable location in urban Corpus Christi, waiting until night to safely continue on its journey.

During a window collision survey around the Nueces County courthouse, I came upon a female ruby-throated hummingbird, trapped upside down in a crack in the pavement. I suspect she had bounced off a window and landed upside down. She was still alive, but she would not have survived for long if I had not found her. This same building killed over 300 Indigo Buntings in one night decades ago. While most birds that collide with windows die upon impact or shortly thereafter, many survive and remain stunned around the structure they hit. In this state, they are more vulnerable to predation by other animals.

Collision deaths by Gretchen Nareff

It‘s estimated that window strikes kill around 300 million birds every year. But we can reduce these numbers by making small changes to our infrastructure and homes and planning new construction appropriately.

Ideas for Helping the Birds

There are several options for making the windows of existing buildings or homes more bird-friendly.

It can be as simple as placing small stickers on your windows or as intricate as etching artwork into the glass. You can even hang special “wind curtains” to help break up the window reflection.

Wind curtains installed at Chincoteague National Wildlife Refuge. Photo by USFWS

To help with lighting issues, integrate automatic lighting timers, motion detectors, and dimmers to keep lights off or low during peak migration hours. If you decrease the illumination area of the building or home and keep any lights pointed downward, this will also help. By minimizing the reflection of existing vegetation on buildings and preventing future reflections by considering your landscape and the trees around the building. Ideally, any new construction would incorporate bird-friendly designs, including bird-safe glass and awareness of the proximity to natural foraging areas.

Patuxent National Wildlife Refuge hired the help of Lynne Parks from Lights Out Baltimore who worked with artist Chris Siron to design window treatments that would cut back on bird collision.

Left: Before — see the reflection? Right: After — Photos by Lynne Parks
Patuxent Research Refuge has added some attractive window treatments to decrease bird strikes. Photo: Jen Chin/USFWS

There are twenty-nine cities in the United States are part of the U.S. Fish and Wildlife Service’s Urban Bird Treaty program, which encourages bird-friendly practices in local communities. The program adds new cities every year, so if yours isn’t on the list, you could encourage them to join the network.

If not, there is still plenty you can do to help our migratory songbirds safely reach their breeding and wintering grounds. Check with your local Audubon Society chapter to see if they participate in a lights out program or morning bird surveys around buildings. Walk around your own home or office building early each morning to look for downed birds, especially birds that may be stunned and still alive. Place live birds in a small box, without food or water, and place it in a dark, quiet area to help them recover while you contact a local wildlife rehabilitator. If you notice a part of your building has recurring problems, you could try experimenting with different modifications.

One of the most important things we can do is reach out and contact building managers and city officials to make them aware of the problem and encourage them to take measures to prevent future collisions. You can also talk with your friends, family, or co-workers, and make it a true community effort.

Birds are intrinsically important, but they also play an important role in local economies by providing recreational opportunities and irreplaceable ecological functions such as insect control and pollination. Human modification of the natural landscape will no doubt continue, but with some effort, we can make the landscape a little safer for our beloved birds.



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