Wednesday, December 5, 2018

Fatal Reflections

Sometimes, the only evidence we see that a hawk visited the yard is this.

Feathers on the window.

When the hawk swoops through the yard on the hunt, the hunted birds panic. They bolt for the nearest cover.

Sometimes, that 'nearest cover' is an illusion. A reflection in the window. And in their panicked flight the birds crash full speed into the window. Birds are rather light, and pose no threat to the window. Sadly, the same cannot be said for the window to the bird.

As noted in that linked post we've taken steps to mitigate this problem. In the image below you can see a bit of green paracord in the upper right corner. The reflection of the cord is also visible in the window. This cord sways in the wind and catches the birds eye, causing it to focus on the cord and not the reflection of trees in the glass. Obviously, it doesn't always work.

The image below, looking out our living room window, shows the cord and a pair of butterfly decals. The decals are said to reflect light at wavelengths the birds can see. Again breaking up the reflections.

Hopefully the butterflies, shown here from the outside looking in, are more prominent visually to avian eyes (although further research indicates that we would need many more decals, spaced approximately four inches apart, in a grid pattern on the window to be fully effective; there is just too much space for the birds to fly 'into').

Another strategy is to place the feeders either very close to the windows, so the birds can't build up much momentum before they strike the glass, or sufficiently far away so that they have time to recognize the danger and veer off. Since we've taken these steps the number of strikes, and the number of fatal strikes, has been significantly reduced. Placing the feeders such that they are not directly across from windows may also help.

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Window strikes at home feeders are not the only problem. Strikes on office buildings are a major cause of bird mortality, especially during migration at night, when birds, attracted by lights, fly into the windows. The good news is that there are mitigation strategies for both new construction and existing buildings. The sad news is that through ignorance and indifference these strategies are rarely implemented. Groups such as the National Audubon Society and FLAP are working to change this. They deserve your support.

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