Each day I try and take a walk around the Lab of O; in this case, I’m not sightseeing or birding, or even on a trail. I stalk the space within a few meters of the physical building, eyes scanning the ground for a patch of color that stands out from the green or the gravel. Many have spoken of the new Lab as being a beautiful building in a beautiful setting, but upon further reflection, this building’s beauty betrays birds. The energy-efficient, UV filtering windows that offer unimpeded views of Sapsucker Woods pond and the surrounding forest offer birds a lethal reflection of their environment, and from time to time this reflection results in the death of a bird.
A few caveats before I go further: I work for the Lab, and know that everyone working here cares about the issue of windowstrikes. In fact, the oddly proportioned windows in the Observatory of the Visitors’ Center, with their deep mullions and multitude of frame sizes, were originally thought to reduce the likelihood of strikes (and who knows-perhaps they do?). This general pattern was carried out throughout the rest of the building’s exterior, and all of the windows face habitat (except those on the East side of the building). Yet windowstrikes still occur, though my general impression for the past year is that windowstrikes peak during migration periods, with the Fall migration having the highest proportion due to naive juveniles.
The stalking I mention in the first paragraph is a part of my windowstrike monitoring effort here at the Lab. So far this summer, there have been very few reports of birds striking windows (from those Lab staff lucky enough to have a window), and no dead birds have been found beneath the windows. One incident involved the veery pictured above. I received an email from someone on the first floor, north side, that something had struck their window; I didn’t see this email until 15 minutes after it happened, and when I arrived on scene to check on the bird I found a veery sitting calmly underneath the window, breathing regularly but seemingly in a daze. After a few moments in a dark box the bird perked up, and within moments it had flitted off to the low bushes and begun preening (and I breathed a sigh of relief).
Though this veery appeared to be OK, research has shown that even birds that fly off after hitting a window may suffer long-term or fatal effects. Dr. Klem of Muhlenberg College (probably the person best known for researching window collisions) has conducted numerous experiments looking at what influences window collisions and the aftermath of windowstrikes, and has found that up to 30% of those that fly off eventually succumb to injuries derived from the collision. He estimates that over 1 billion (yes, that’s with a “b”) birds are killed each year in the U.S. from window collisions–which is nearly 5% of our total population of birds.
In an attempt to lower that number and too educate the public about the issue I am developing an exhibit around windowstrike mitigation options focusing on both high-tech and low-tech solutions to the problem. Since the exhibit isn’t quite done yet, I thought I would share some of the main ideas here, as well as link you to Audubon’s page about reducing windowstrikes:
- Look at where windowstrikes occur at your house/building. Sometimes only a few windows are problematic, and treating those windows first (or concentrating you efforts there) will result in the greatest reduction.
- While it may seem non-intuitive, placing feeders less than a meter away from a window greatly reduces the likelihood of serious injury from a windowstrike.
- If you are planning on building a house with large banks of windows, consider angling the windows towards the ground at an angle of 20-40%. Angling has been shown to significantly reduce windowstrikes and collision injuries by reducing reflections and decreasing the force of impact. Also, consider whether your budget can accommodate the use of ceramic fritted glass, which is glass with small ceramic “frits” printed on the outside surface that break up the reflection but are small enough to not interfere with transparency. Its suitability and efficiency is currently being tested at several Universities.
- Window decals, when placed on the outside of the window, can be an efficient deterrent to window collisions; however, in order to be effective the decals must be no more than 6-8 cm apart across the entire face of the window. The same effect can be achieved using hanging streamers, CDs, etc., but they must adhere to the 6-8 cm distribution as well. Many people feel this defeats the purpose of a window, but for those who don’t mind a little bit of visual obstruction, this option is the cheapest.
- Consider covering the windows with a one-way laminate that is opaque on the outside but can be seen through from the inside, like Collidescape. This laminate is often used for advertising on windows, so that the windows are covered with ads when seen from the outside, but transparent from the inside. This option is by far the most expensive fix.
- An alternative to laminates, Birdscreens are fine mesh screens that are nearly transparent from the inside and affix to the outside of the window with hooks and suction cups. They come in a variety of sizes and are easily removed for window cleaning.
If you want to see the last three suggestions in action, swing by the Lab later this summer and check it out. You’ll probably see me walking around the perimeter, one eye on the ground and one on a less-reflective future…