Urban Green Council Executive Director Russell Unger recently spoke with Bruce Fowle, Founding Principal at FX FOWLE Architects about buildings and bird safety – an issue that has been important to Bruce for many years. Research by leading scientist Daniel Klem [PDF] estimates that at least 100 million and up to 1 billion birds are killed annually by collisions with buildings and other man-made structures in North America alone.

Russell Unger: How did you get involved in this subject?

Bruce Fowle: I would have to attribute most of it to my wife Marcia, who grew up in a birding family. She had been asking me for years what I was doing about all these birds that were killing themselves by colliding with glass – “what are you, Mr. Architect, doing about this?” So I had this guilt trip every time I put up a piece of glass. Then Marcia became Executive Director of New York City Audubon, where she then really put the pressure on. She has since served as President of the Board there and has written a book on birding in the New York City area.

I had spoken out on this issue and made myself known as somebody who was concerned about it from the architectural side, and was invited to speak at a Conference at the Illinois Institute of Technology in Chicago in 2005 (Birds and Buildings). The conference was at IIT for the obvious reason that the original Mies van der Rohe buildings were killing birds by the thousands every year with all that glass; they were the first real all-glass or almost all-glass buildings in the U.S. This conference really kick-started the whole movement, which New York City Audubon picked up on and eventually led to the writing of the Birdsafe Building Guidelines under their auspices. Groups in Chicago and Toronto have made similar efforts.

RU: What’s the scope of the problem?

BF: Well, there’s a scientist–Daniel Klem at Muhlenberg College in Pennsylvania–who has been doing testing and analysis of this for probably 25 years. Based on rough calculations, he has concluded that a billion birds a year are killed in this country alone by colliding with buildings. Most of the birds that collide with glass tend to be the smaller songbird species – and a lot of these species are already endangered because of loss of habitat, climate change and so forth. Glass buildings are one more factor contributing to their demise.

There are three primary conditions that contribute to this problem: lights at night – which draw birds to buildings or other illuminated features during migration; transparency – when a bird sees daylight beyond or an illuminated tree it can roost on and thinks it can fly right through the glass; and reflectivity – when a bird sees sky or vegetation in the reflection from the glass and flies into it.

RU: So the worst thing in the world for a bird would be someone living in a glass house full of searchlights?

BF: [laughs] Yeah, with cats and a birdfeeder.

RU: Why should design professionals and New Yorkers in particular care about this issue?

BF: Anything that is contributing to the loss of wildlife is a problem from most people’s point of view, unless you’re a wolf hunter in Idaho or something like that. And it’s just getting worse as more and more buildings are designed as all glass. New Yorkers in particular should be concerned because New York – along with Chicago and Toronto – is along a major migration flyway. Buildings in these cities become lethal objects for migrating birds. Migration usually takes place at night, and then if there’s an overcast condition the birds tend to fly below the clouds where they lose their celestial navigation aids and are drawn to lights illuminating the outside of buildings or towers or other lighting events. The 24/7 phenomenon of many businesses today exacerbate the problem by keeping their work lights on all night without shades or other devices that might deter birds.

RU: What’s the ultimate solution to the problem?

BF: We’re now at the point where we put low-e coating on glass for performance purposes; I think it’s actually required by law in many locations. You probably can’t buy an Anderson window from your hardware store that doesn’t have low-e coating. So what we need is a low bird-kill coating or something that the birds can see that doesn’t disturb the human eye. To require something like frit patterns for every light of glass in the world is just not realistic, but if there is something you can you just throw into the mix – into the process of making glass – that would be the ideal solution.

RU: How close are we to this?

BF: There are certain visual frequency ranges that birds can see that humans see less of, and one is ultraviolet. There have been a number of experimentations using that type of coating, either as a coating or as a mix into the glass that reflects the ultraviolet rays in a manner that is barely visible to the human eye. There’s a company called Arnold Glas in Germany that has a glass that’s called Ornilux glass, which has been around for 10 years now or so. We put some of it on the Center for Global Conservation at the Bronx Zoo.

Unfortunately it’s more expensive than traditional glass and we couldn’t afford to put it on the whole building. The portions where we used it have been very successful; there have been no bird kills. The portions where we didn’t use it have been dramatically different. We’re working on solving the problem for the rest of the building by putting something a frit-like pattern on the rest of the glass. It’s an ongoing project and affords us a great working laboratory to test ideas.

RU: What about hawk decal stickers and that type of thing – do these help to deter birds?

BF: No, testing shows that these don’t work. There are testing tunnels in Austria and Pennsylvania where they release the birds on one end with panels of glass set up on the far end. One side of the glass might have a pattern or film on it and the other side might be clear, and then they watch what the birds do as they fly toward the light. Of course they have a net so the birds don’t kill themselves. This affords a good sense of what works and what doesn’t work, although it does not address all the conditions, such as reflectivity and nighttime conditions. They’ve determined that patterns with negative space no greater than roughly the size of your hand, say 4 inches wide by 2 inches high, will deter most birds from flying into it. This is now the accepted minimum scale of markings, and we’ve developed a number of patterns using this scale that we think are architecturally interesting, but we haven’t tested them yet. It’s on ongoing effort to find funding for such testing.

RU: What specific things should a designer consider in order to reduce bird kills from their buildings?

BF: The first thing we really need is a zoning map or something like that that identifies where the problem can be anticipated. We know if you have reflective glass right next to a park, for example, it’s an automatic killer because the birds think that they’re just flying into another tree. We need to figure out how to clearly identify where the problem exists, so if a developer or owner buys a piece of land they know that they’re in the bird-kill zone and have to deal with the issue. Otherwise, it’s very hard to convince most people to spend money on this sort of thing just out of the goodness of their heart.

Once you identify that you have a problem, there are a number of things that can be done. For example, with the Goldman Sachs building in New Jersey, Cesar Pelli got an innovation point by creating angled, serrated glass on the top of the building, creating visual noise for the birds, which is a collision deterrent, as was the frit pattern they put on the opaque portions of the glass façade. We know that there are certain frit patterns that work, but that problem is that it can impact the marketability of a project because not everyone wants to look through that pattern.

That’s where this new type of glass with ultraviolet reflecting qualities becomes an important option, but there are still a number of issues with that. If you’re putting a reflective coating on it to make it high-performing, the reflectivity will make it less effective from a bird-safety perspective. The general rule is the glass should be 15% reflectivity or less for bird safety, where glass has been traditionally closer to 30-35% reflective over the last 15 or 20 years – which gives you total reflection of sky or vegetation.

RU: What steps still need to be taken to confront this issue?

BF: I think that it’s eventually going to be regulation, which has happened in Chicago.

The Bird Safe Glass Foundation that Marcia is involved with, along with the American Birding Conservancy, was able to identify an innovation point for bird safety in the 2009 version of the LEED Reference Guide, which is an important step towards creating a market and getting people to innovate and think about the issue. It’s still disturbing to people who care about this issue that you can have a LEED Platinum building and have it be one of the worst bird killers you could possibly create. How can a building be called green if it is having a serious negative impact on wildlife? I know that they already are, but hopefully USGBC will continue moving more in this holistic direction.

Learn more about this important topic on January 5th at our 1st Wednesday Technical Roundtable: Building a Birdsafe City.

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