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Flight or Fight: The Challenges Facing Birds in Spring

A male Northern Cardinal faces his reflection in a car's side mirror.
A male Northern Cardinal faces his reflection in a car's side mirror.
[photo credit:]


The Problem with the Flight

As our migratory birds return to spring habitats, it’s a wonderful time to watch behaviours specific to this time of year.

Many species migrate in large flocks, but once they arrive, their mating displays and territorial behaviours kick in.

They chase or are chased by other birds over mates or territory and when they see the reflection of trees or sky in our home windows, they think they can fly into and through them. And that’s when we hear that dreadful “thud”.

The number of birds that die from window collisions, according to Ontario Nature, is astounding:

  • 1 million in the Greater Toronto Area
  • 25 million in Canada
  • 1 billion in North America

And they are preventable.


Bird-Proofing Windows

There are many ways we can prevent our windows from looking like a safe thoroughfare for birds. Eliminating the reflection is easily done by closing curtains or shutters.

Other home-made solutions include soaping windows or marking them with a wet-chalk marker (only in protected areas though where rain won’t wash them off).  Industry recommendations vary in spacing of dots or lines, but most agree that the safest pattern is 5cm by 5cm (2 in. x 2 in.).   

There are many products on the market that can be applied to windows to break up the reflection and prevent birds from collisions, including decals, transparent films and exterior screens.

In our shop and online, we carry several products to help prevent or eliminate bird collisions with windows.

Feather-Friendly Tape comes in 100 ft. rolls and with a simple application process, you’re left with an attractive pattern of square dots.

And a new product to the store, mentioned in the April 2024 newsletter, is Window Gems, static cling decals which bring beautiful rainbow prisms of sunlight into windows while protecting the birds.  For more photos and a helpful FAQ section, visit their website at


The Problem with the Fight

In defence of both territory and possible mates, most birds will act aggressively chasing competitors out of their range and away from their mate. Birds who frequently nest close to houses may perceive their reflection in windows as a rival and spend precious time and energy attacking the perceived opponent. These include Robins, Northern Cardinals, Bluebirds, Chipping Sparrows and Song Sparrows.

Northern Cardinals are famous for attacking side mirrors on vehicles, “fighting” a perceived opponent who won’t leave. Eventually, the cardinal will move on from this battle, but not before precious energy is wasted and the vehicle has been peppered with droppings (mostly a result of anxiety battling such an impressive rival).  

Covering the side mirrors with plastic bags, toques or a towel may help; just be sure to remove them before driving the vehicle.

Hopefully some of these options will help reduce bird/window impacts in your home so you never have to hear that ominous thud or find an injured or dead bird as a result of untreated windows.

Happy Spring!