Toronto’s Fatal Architecture

Toronto is one of the world’s most dangerous cities for migratory birds, with an estimated nine million dying each year after crashing into the city’s glass towers.

So many birds hit the glass towers of Canada’s most populous city that volunteers scour the ground of the financial district for them in the predawn darkness each morning.

Toronto’s modern skyline began to rise in the 1960s, giving it a high proportion of modern, glass-clad structures, forming a long wall along the northwestern shore of Lake Ontario. That barrier crosses several major migratory flight paths, the first large structures birds would encounter coming south from the northern wilderness.

Glass facades next to parks can disorient birds by reflecting the surrounding trees. Perceiving the reflection as habitat, birds zoom at it full throttle without regard for the danger.

The victims are largely songbirds. Perhaps because of familiarity, the urbanites of the bird world, like house sparrows, pigeons and gulls, are much less prone to crashing into glass.

One especially effective, if unpopular, method of reducing the threat to birds, is simply to cover the outside of windows up to the height of adjacent trees with the finely perforated plastic film often used to turn transit buses into rolling billboards.

For new buildings, the solution can be as simple as etching patterns into its glass. A German glass company is also developing windows that it hopes can take advantage of the ability of birds to see ultraviolet light, by including warning patterns that are invisible to humans.