Posted | filed under Weekly Banding Reports.

As the LSLBO enters the lull in migration that often occurs mid to late August, we are left wondering where all the Myrtle Warblers are. This subspecies of the Yellow-rumped Warbler tends to be our top captured and observed songbird, but at 177 banded they are only in fourth place. While we wait to see if the Myrtles will come, we have used this lull to make our lab safer for birds.

From cats to cars, there are plenty of hazards to birds’ survival. We know cats are the leading direct threat, but for something that does not move, houses and skyscrapers are a killer in second place. Most buildings are covered in reflective surfaces that do not look like a solid barrier to a bird. Birds hit these windows confused by the reflection, which can be fatal with enough momentum. An estimated sixteen to thirty million birds are killed in Canada from immediate impact, concussion, or opportunistic predation while stunned from hitting windows.

Although most will be picturing skyscrapers, with bedrooms, living rooms, sliding glass doors—our houses are covered in windows. Since there are far more houses than skyscrapers in Canada, of these window strikes, upwards of ninety-five percent are due to residential windows. On the bright side, there are easy fixes – all of which must be applied to the outside. 

Above: Robyn installs a translucent tape to the exterior of the lab’s windows to break up the forest’s reflection.

If reflections are causing confusion, then the simplest fix would be to break up the reflection. Small stickers or decals fixed to the outside of the window help shrink the gaps that birds are comfortable flying through. Remember, however, that birds are used to flying through narrow spaces between trees and shrubs so decorative decals (such as a bird silhouette) may not be enough to prevent window strikes.

The best way to reduce windows strikes is to use dots or stripes spaced every five centimeters (2 inches) or less. Translucent stickers can be purchased specifically for this purpose, often coming in the form of a tape. It is one of these tapes that we used on our banding building’s windows to eliminate window strikes after the disappointing find of one of our first.

Above: A mesh applied over the window absorbs the impact of a strike. Although this mesh is applied to the interior of the lab (in case of escapees), the same method can also be used on a window’s exterior.

Other options include installing external screens or using glass-safe paint to turn your window into a canvas, keeping in mind that the smaller the gaps, the better at breaking up that reflection and the safer for birds. These methods are good even at night, when drawn curtains may block the light from within but not the reflection outside, especially when the moon is out.

Aside from fixing the window, it is possible to reduce the fatality of window strikes. If you have a bird feeder or bird bath, consider moving it less than a meter from the window. The closer to the window the bird is on take off, the less momentum they build up, so even if they do hit the glass, they are less likely to sustain serious injury on impact. As a bonus, the birds are closer for easy viewing.

By Bronwyn Robinson, LSLBO Assistant Bander

Read more: Machtans, C. S., Wedeles, C. H. R., & Bayne, E. M. (2013). A First Estimate for Canada of the Number of Birds Killed by Colliding with Building Windows. Avian Conservation and Ecology, 8(2), 6.