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Window Strikes

Anywhere there is glass, window strikes can happen. Research suggests between 16-42 million birds are killed by colliding with glass each year in Canada. 99% of strikes are suspected to happen at tree level or below. 

Why do birds hit windows

Quite simply put, birds don't see clear glass. Many of us have walked into a clean glass door and we know to expect a barrier there! Now imagine you are a bird and on the other side of the glass is an inviting scene whether it's indoor plants or trees on the other side of the windows, birds will fly towards ideal habitat. If a clear glass pane is in the way, they literally do not see it and will strike. Reflective glass on the other hand also presents a danger to birds as it reflects the habitat directly in front of it, which is often appealing. Reflective glass also reflects back a bird's own image which at certain times can provoke species such as robins to repeatedly bang against glass in an attempt to get rid of a potential rival. 

*Fun fact, as of yet, magpies are the only birds known to be able to recognize their own reflection! 


When do birds hit windows

Any time birds are active, they can hit windows although there are certainly times that appear to result in more strikes. Migration is a particularly high time for strikes.

80% of birds are known to migrate at night and during migration, early morning hours are a likely time for strikes as birds come down into urban areas to rest for the day. However, as they forage in potentially unknown habitat, migrating birds are potentially at risk. Experts have found strikes primarily between pre-dawn and 1pm during spring and fall migration. 

During the summer months, fledgling birds who are just learning how to navigate in the world are at a higher risk. 

While any bird can hit windows whether migratory or resident at any time of day or year, some species may be at a higher risk of strikes according to FLAP Canada. They have compiled a list of the top 20 window strike species for the GTA. Most of the birds listed there, also occur here.  


How we can prevent window strikes

Despite not being able to see clear glass, birds have fantastic vision and can even see in the ultraviolet range! Given this, the easiest way to prevent window strikes is to mark your windows with something visible to the birds! While dark or UV reflecting decals have long been in use, current research suggests that these only show birds there is a barrier in that exact spot and the bird may still hit at a different spot. In order to reduce the risk over the entire window, a 2x2 rule is suggested. This suggests that a barrier needs to be placed every 2 inches to show the entirety of the danger. There are multiple ways to do this: 

1. Get yourself some paint markers and go to town! With the ability to remove the painting at any time, some people have suggested their windows can become a constant blank canvas just waiting for the next inspiration!

2. Feather friendly tape. Not a fan of drawing yourself or don't want your view obscured by paint? Feather friendly tape is the answer for you. Already designed with the 2x2 rule, Feather Friendly is easy to apply and can stay on your windows for years before needing to be replaced. Best of all, after a while, you don't even notice it's there while birds do. 

Other ways to prevent strikes include planting trees and shrubs farther away from windows while counterintuitively having feeders no more than 3 feet away. 

Turning off lights at night will also help keep nighttime migrants on the correct path and preventing them from entering urban areas instead of natural areas. 

Not all windows present the same risk, evaluate your home or workplace using the FLAP App


White-throated Sparrow

D. Arndt

Feather Friendly Tape

K. Johnson

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