bird migration is a necessary process for birds to find areas with more resources like food and nesting areas. but chicago poses a threat to this process, deemed by a study to be the most dangerous city for migratory birds because of bird collisions with windows. chicago bird collision monitors (cbcm) is a nonprofit organization working toward addressing this problem and helping rescue injured birds.

since its inception in 2003, the volunteer not-for-profit organization’s mission has been to document the issue of bird collisions and advocate for the protection of migratory birds passing through the chicagoland area, particularly downtown. cbcm has a hotline operating seven days a week for people to report injured migratory birds near buildings. according to the organization, its members take more than 3,000 injured birds to wildlife rehabilitation centers each year. much of this work is done from mid-august to early november during the fall migration season.

facing an invisible threat

just like humans, birds cannot see glass. however, humans, unlike birds, have found ways to identify when glass is in their sight by finding identifiers like drapes, a frame or a reflection. many birds, before they migrate, come from areas where they have no familiarity with buildings or windows, which is why cities pose a great threat to them.

“the deadly thing for birds is glass,” director annette prince said. “glass can either be transparent and something that birds think they can fly through because they don’t know there’s a barrier there, it can be reflective and look like a mirror showing birds images of sky or trees that they think are real but they don’t realize again that there is a surface that they’re going to fly into and they should avoid.”

cbcm receives almost 12,000 calls a year about birds that need help, and volunteers find nearly 7,000 birds a year.

prince explains that chicago is in the migratory path of birds as they travel from as far north as the arctic circle down to south america. over 250 bird species fly through chicago annually.

“[the chicago area] has been used by birds for centuries and we have just had tall buildings with bright lighting here for the last 100 years,” prince said. “so, we have put obstacles in their way when it used to be a safe place to travel.”

coordinating with community

volunteers of cbcm help migratory birds by taking calls for the group’s bird collision hotline (773-988-1867), transporting birds to wildlife centers, spotting injured or dead birds in the chicago downtown area and making donations to the organization. 

cbcm’s hotline is open 24/7 and when people call, they receive instructions for connecting with a nearby volunteer, safely containing a bird as they wait for help, taking a bird to a safe location until they can be taken to a wildlife center, or the caller can give directions for where the bird can be found by cbcm.

the two birds that are found the most often are brown creepers, small songbirds that are usually brown with brown and white speckles and a white belly, and white-throated sparrows, which are brown with a gray belly and a black and white striped head, prince said.

volunteer transporter lorna lightle said she picks up birds so often to transport them to a wildlife center that in addition to getting calls from the hotline, many people call her personal number. she said that people can help volunteers by doing what they can on the scene when they find a bird or transport them a portion of the way to their destination, whether a volunteer’s home or a wildlife refuge. 

becoming bird-friendly

“don’t give them water. try and get it back in the nest… if it’s had a collision with a window, the best thing is to do is put it in a box. let it hang out for a little bit, see if it regains composure, and (the bird) might fly off on its own before you need to bring it to us,” lightle said. “there are options. get it to a cross point, and then somebody else can take it the rest of the way, then you really are helping the bird and helping the organization.”

if a dead bird is found, chicago bird collision monitors sends the bird to the chicago field museum — focused on natural history — for documentation where it can be researched to understand the magnitude of the collision problem.

the organization also advocates for bird-safe architecture by making recommendations for patterned glass, screening in front of glass, using less glass in building designs and having protected green spaces on buildings that do not use illuminated objects that attract birds. it’s easier to make a building bird-friendly during initial construction rather than making the costly decision to retrofit it after it’s completed, prince said.

solutions for bird collisions

1. make home windows and glass objects visible to birds by creating markings and designs with paint, or add temporary installments such as hanging cords in front of window screens. 
2. turn off lights at night as birds use light sources of the moon and stars to navigate and can be thrown off course by artificial lighting.
3. monitor the movement of migratory birds in your area by watching the bird cast, which uses the weather to predict how many birds will fly through an area. 
4. while it is not recommended to feed wildlife because they have natural food sources, you can help migratory birds by feeding them a healthy diet with regularly cleaned and elevated bird feeders as many migratory birds often look to refuel during their trips. 
5. if you can, maintain a natural garden with native and pollinator-friendly plants.

healing chicago’s birds

cbcm collaborates with multiple wildlife centers to get medical attention for birds with injuries of all magnitudes. the willowbrook wildlife center — a rehabilitation center in glen ellyn, il promoting the harmonious coexistence between wild birds and humans — has a partnership with cbcm. the center is a hospital for wildlife dedicated to returning mammals, reptiles, amphibians and (mostly) birds to the wild. while the center works primarily with species native to northern illinois, others tend to pass through during migration. 

cbcm brings injured birds to willowbrook every day, according to wildlife education supervisor for forest preserve district of dupage county stephanie touzalin. most of the birds received by willowbrook through cbcm are stunned birds — unreactive birds that are generally unmoving and have squinty or fully closed eyes. although, by the time they arrive at the center, they have generally recovered, touzalin said. still, the center does receive badly injured birds as they are hard-hit when they fly into windows.

“[cbcm volunteers] put birds in little paper bags and so when they arrive here, often the bags are kind of jumping because the birds have recovered a bit more,” touzalin said. “we do sometimes see eye injuries, knee injuries, sometimes leg fractures. they can sometimes break like their coracoid, which is kind of like the collarbone area. but, a majority are probably stunned and otherwise injury-free.”

a majority of the birds, particularly those that are stunned, are released the same or next day they arrive. the birds receive a test flight in a space where they cannot escape. often when the animal care staff at willowbrook opens the bags birds are held in, they fly right out. if the birds fly properly, without being tired or out of breath, they are ready for release, touzalin said. 

are clear skies ahead?

most birds are received by wildlife rehabilitation centers during the peak of migration periods. during the spring, the peak is mid-may, and during the fall, the peak is late september to mid-october. these are times when most birds are moving because weather conditions are optimal.

there are various ways people can make their homes save for passing birds. it is crucial for people to understand the danger glass poses to all birds and make the changes necessary to their homes for birds to continue their natural process of migration, touzalin said.

“glass is not an indiscriminate killer. it’s not like it weeds out the weak individuals. it can take out any bird: the strongest, most healthy bird to the weakest bird because it’s universally something they don’t understand or recognize,” touzalin said. “it’s really important that more people are aware of it and knowing that here, we’re very lucky to be along the migratory pathway that we get to see all these really cool birds, but then important to make it safe for them.”