Believe it or not, fall migration is already underway.
But it’s a harrowing journey back north for the hundreds of bird species that will fly through Wisconsin.
Window collisions are a leading cause of bird deaths, causing up to 3.5 billion bird deaths in the U.S. each year, according to a recently published study in The Wilson Journal of Ornithology.
They’re even more common in the fall when both adult birds and their offspring migrate, but these dangers exist for birds year-round.
For this month’s Chirp Chat, Lake Effect’s Xcaret Nuñez spoke with Brenna Marsicek, director of outreach for Southern Wisconsin Bird Alliance and Lisa Gaumnitz, coordinator for SOS Save Our Songbirds, about the ongoing efforts to make places more bird-friendly.
What makes birds vulnerable to window collisions?
Birds can’t see glass surfaces, especially glass near bird feeders and bird baths.
During the day, Marsicek says window collisions happen from birds mistaking reflections of open skies or nearby trees for the real thing. At night, when most birds migrate, she says lit-up buildings distract birds away from their migratory paths and into collisions.
“While the lights themselves don't kill birds, the glass does — the actual draw effect of those lights is pretty significant,” Marsicek says.
She also says the physiology of birds also plays a role in making them susceptible to window collisions.
“A songbird's eyes are placed on the sides of their heads so that they can better see predators around them, but it changes the way that they perceive depth — especially for something that's reflective, like glass,” Marsicek says.
Birds also have hollow bones, which make them light enough to fly. That means when they collide with glass at high speeds, they’re more likely to get severely injured.
“There have been studies that categorize [birds] that are most at risk, and some of it has to do with their population size,” Marsicek says. “So, a species that is already in decline and often hits windows gets bumped high up on that vulnerable list because they just don't have a lot of that bird [species] on the planet anymore for them to lose that many.”
Marsicek says common birds to hit windows include:
- Ruby-throated hummingbirds
- Cedar waxwings
- Yellow-bellied sapsuckers
- American robins
- Mourning doves
- Tennessee warblers
“Many of [these birds] are long-distance migrants, which makes sense because in spring and fall, these birds have to fly, and they're flying fast, and so they're just more likely to be flying in an area where there's a building,” she says.
What’s being done to make places more bird-friendly?
Volunteer groups like the Bird Collision Corps, a Madison-based community science project, work to study how window strikes cause bird deaths.
Marsicek says Bird Collision Corps volunteers are assigned to buildings every spring and fall and look for birds on the ground that have been killed or injured upon impact with the building. The data volunteers collect is then recorded on iNaturalist, a crowdsourced scientific database.
“At the end of the season, after all these volunteers have spent hundreds of hours surveying buildings in the Madison area, we analyze it, and then we report it out, both to the volunteers and to the building owners,” she says. “So ideally, if our volunteers have found a collision hot spot, we have a way to suggest that the windows be addressed to reduce collisions in the future.”
Marsicek says the data Bird Collision Corps has collected over the years helped influence the Bird-Safe Glass Ordinance that the City of Madison unanimously passed in 2020.
After years of litigation from developers, the Wisconsin Court of Appeals upheld the state’s first bird-friendly building ordinance late last year. Middleton, Wisconsin, then approved a similar ordinance last October.
Marsicek says the ordinance requires any building over 10,000 square feet and using a certain amount of exterior glass, must use bird-safe glass, such as frit glass — a pattern that’s baked or etched into glass.
“That frit would have to be in a 2-inch-by-2-inch grid or spaced in some way where nothing on the glass is more than 2 inches apart from something else,” Marsicek says. “That 2-inch rule is really important because birds are great at flying and can try and squeeze through tiny spaces, especially small birds like hummingbirds. So that 2-inch rule makes sure that it's the most effective pattern on the glass to reduce collisions.”
Gaumnitz with SOS Save Our Songbirds says several buildings throughout Madison, including a handful of bus stops, have installed bird-friendly glass. Most recently, Gaumnitz says the Henry Vilas Zoo installed bird-friendly glass outside the popular building that houses its carousel.
“It was one of the buildings [Bird Collision Corps] volunteers did their rounds at during the spring bird migration, and it was found to have more of a [collision] problem than others,” she says.
In Milwaukee, the American Bird Conservancy played a major role in making Fiserv Forum, the home of the Milwaukee Bucks, the world's first bird-friendly arena in 2018.
“It's really something to be proud of, that this huge building decided to take the initiative to put in this bird-safe glass and show that responsibility to the environment and the community around them,” Marsicek says.
What can I do to make my windows more bird-friendly?
Marsicek and Gaumnitz say there are numerous ways to make your home more bird-friendly, including:
- Insect Screens: It’s a common household item, yet it’s extremely effective at reducing the reflectiveness of glass and offers a buffer between the bird and hard glass surface.
- Feather Friendly Dot Decals: These semi-permanent dot stickers are applied to the outside of your windows in a 2-inch-by-2-inch grid.
- Tempera Paint or Oil-based markers: A weatherproof option that allows birders to get creative and draw a design on the outside of windows — but it will only work if gaps are 2 inches wide.
- CollidEscape Tape: Translucent tape produced by the American Bird Conservancy that you can apply directly to glass.
- Acopian BirdSavers: Also known as “zen curtains,” these paracord curtains are made out of material used in parachutes and hang in front of the glass.
If you’d like to explore more options, the American Bird Conservancy has tested numerous bird-friendly products and created a database on where they rank based on various factors.
You can also learn about Audubon’s Lights Out Program to make your neighborhood or hometown safer for migratory birds at night.
Chirp Chat’s Birds of the Month for September
“My favorite bird to watch at this time of the year would be the American goldfinch,” says Gaumnitz. “They’re a small bird that has a bright yellow color, and it's got black wings that have some little white stripes on them. It's almost like a flying lemon. It's likely that people are seeing it around their home if they've got a feeder, but also, if they're going to [prairie-like areas], they'll see it as well. But I believe it's one of the latest nesters in Wisconsin, and so it's one that people can still look for feeding young. Sometimes they don't take off and migrate until late September.”
“The bald eagle is such a wonderful conservation success story where, not that long ago, 50 or 60 years ago, they were on the brink [of extinction],” Marsicek says. “And through a lot of different people working together and being thoughtful about the ways that our actions impact birds, we eliminated DDT from the environment, which was a big thing for bald eagles and other raptors… It's just such a wonderful way to represent collaboration and people being intentional about saving things that they care about… they’re just such a wonderful sign of ‘this is success in conservation.’ This is one example that we did it once, we can do it again.”
