Keep migratory birds safe this fall

Red eyed vireo on a branch

With fall around the corner, millions of birds will migrate through the Credit River Watershed to their wintering grounds in the southern US or the tropics.

Our watershed is where the Atlantic and Mississippi migratory bird pathways meet, yielding an abundance of migrating birds. They tend to follow river valleys to make their way to the Lake Ontario shoreline.

Bird with yellow head
Black-throated Green Wabler. Photo Credit: William H. Majoros

Birds face many challenges during migration. In urban areas, one of the biggest challenges is collisions with windows, or window strikes. In Canada, it is estimated that 25 million birds die from window strikes every year. Most collisions happen during spring and fall migration when large numbers of birds are on the move. The reason: birds simply can’t see the glass.

During the day, windows reflect a lot of light. Birds see plants and sky reflected in the windows. They fly towards plants seeking shelter. Additionally, birds may see houseplants on the other side of a window and mistakenly think it’s outdoors, leading to a window strike.

Bird perched on branch
Yellow-rumped Warbler. Photo credit: Dan Pancamo

Many birds migrate at night using the stars, moon and sun to navigate. Unfortunately, for reasons not fully understood, birds are attracted to artificial light and drawn into our urban environments. Foggy and rainy nights when clouds are low force birds to fly lower in the sky, increasing the risk of window strikes.

Fortunately, there are things we can do to prevent this:

  • Apply visual markers to windows like frit or film
  • Keep bird feeders and baths less than 1 metre from windows
  • Move houseplants away from windows
  • Leave window screens in front of windows
  • Turn off your indoor lights when you are not using them
  • Take injured birds to qualified wildlife rehabilitation centres

Homeowners and building operators can learn how to prevent window collisions at

Bird perched on branch
Ruby-crowned kinglet. Photo credit: Donna Dewhurst – U.S. Fish and Wildlife Services

You can also become a citizen scientist by reporting collisions through iNaturalist or FLAP, Canada’s Global Bird Collision Mapper. These online mapping tools allow you to submit the location and species that struck windows. We encourage you to report window collisions and upload a picture so we can gain a better understanding of where window collisions occur in our watershed and what species are most vulnerable.

By CVC’s Christina Kovacs, Specialist, Natural Heritage Management

Comments (3)

    1. Hi Andrew, this is what our expert has to say in response to your question: Less than 1m is best, less than 5m is ok, 5-10 m is the danger zone, and anything more than 10m of ok too. It is related to how hard they will hit the window. If feeders are close they won’t get up the speed to do severe damage but if they are 5-10m away they can build up a lot speed and the chance that the collision is fatal is high.

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