Maybe it was at home when you first heard it. The loud thud at the window. A bird strike.
While they may seem like rare events, bird strikes into windows are actually very common. They’re the number two killer of wild birds in the country, after habitat loss.
But no one really knows how many birds die this way, and how much damage it’s doing to bird populations. The best estimates put the death toll at hundreds of millions per year. In Portland, the Audubon Society is leading an effort to get some answers.
Earlier this month I joined Mary Coolidge with the Audubon Society of Portland on a survey of bird deaths in South Waterfront. She’s been leading a team of volunteers that hit city streets shortly after sunrise to count how many dead birds they find.
They get up early because that’s the best time to get the most accurate counts. Scavengers and maintenance crews quickly carry away bird carcasses once the sun is up.
The Audubon Society has a grant from the Oregon Zoo to carry out this research, called the Bird Safe Portland program. They’re trying to find out what parts of town and what kind of buildings have the highest death counts. They hope the information will lead to voluntary bird friendly building guidelines in the city of Portland.
It may seem strange to us, but birds just don’t perceive windows as a barrier. During the day, reflections of the sky, clouds and trees confuse birds into thinking that there’s a clear path ahead of them.
At night, birds are naturally attracted to lit up buildings. This is when most birds migrate, even diurnal species that are usually active during daytime. Birds may fly into windows hoping to reach the light. They may also circle lit buildings for hours until exhaustion takes over and they fall to the ground.
One solution is convincing office buildings to reduce lighting after business hours. Several cities have started these Lights Out programs. In Chicago for example, bird strikes were reduced by 80%. Turning off the lights also saves energy.
In the video, Coolidge talks more about the problems getting accurate information, and how windows and lights confuse birds. On my visit with her, she didn’t find any dead birds. But that doesn’t mean the problem isn’t a serious one.
(Continue past the video for links on how to make your home or office more bird friendly)
For more information:
Audubon Society: Bird Safe Portland
