Building Bird Collision

Each year hundreds of millions of birds die in collisions with man-made structures that are mostly windows and buildings, communication towers, and wind turbines. The rates of mortality of birds that collide with different types of man-made structures are different. To get an idea of these rates in the United States alone, consider the following estimates:

Based on these estimations, we can see that up to one billion birds are killed every year in the United States by flying into plate glass windows. This by far is the first reason behind birds’ death. Unlike some sources of bird mortality that predominantly kill weaker individuals, there is no distinction among victims of glass. Because glass is equally dangerous for strong, healthy, breeding adults, it can have a particularly serious impact on populations.

Much of this mortality takes place during spring and fall when songbirds are migrating. While songbirds are most at risk from collisions with glass, nearly 300 species have been reported as collision victims, including hummingbirds, woodpeckers, kingfishers, woodcock and birds of prey. We do not usually see dead stricken birds by the buildings. It is most probable that they die elsewhere as a result of the collision. The injured may also be eaten by a cat, raccoon, fox, or dog before we found them.

In fact, birds cannot perceive transparent or reflective glass as a barrier to be avoided. During the day there are two possible scenarios. First, they don’t detect the reflected scene by windows. The hazard to birds is even greater when there is more natural habitat around thus the scene seems more real, and when there are large panes of glass.

Second, when there is a transparent glass that allows views of habitat on the other side of a building or views of plants inside the building: 

Birds can't see glass and don't understand the architectural cues, such as window frames, mullions, and handles, that help people detect it

Even small windows can be dangerous to birds that are accustomed to flying through small gaps between trees and shrubs:

During the night, there is another reason for bird collisions. Lighting is an attractant especially for migrating birds who often fly at night. Brightly lit buildings can draw birds in where they can hit windows or other obstacles. It is said that in cities the biggest kills typically occur at night during spring and fall migrations, when building lights appeared to lure birds into deadly collisions.

In this picture each little spot is a migrated bird that has been trapped in the light beam. They circulated in the beam for several hours until some people reported to turn off the light. 

In order to mitigate the rate of building bird collision, it is recommended to incorporate bird-safe design elements into new architecture for commercial buildings and homes at early stage. In case of existing buildings, retrofitting is another solution: For example, applying tape, film, paint, or decals to the exterior to create visual barriers; installing netting in front of the glass or using exterior shutters; and modifying interior and exterior lighting regimes.

In broader view to this problem we can notice that, while all native birds are protected by law, such sources of mortality (i.e. window collisions) are simply overlooked. Now a few communities have some requirements in this case. For instance, the City of Toronto has new requirements for bird-safe design. Minnesota has a state law requiring all state-owned and leased buildings to adhere to “Lights Out” parameters to benefit migrating birds and save energy. And Federal legislation has been proposed requiring bird-safe design for federal buildings. (To get the Minnesota Bird-Safe Building Guidelines click here)  

In case of green buildings, LEED has applied some criteria to mitigate this problem (Green buildings by having ample openings, windows and attractive environment for birds, have a potential risk of collision). Provisions related to bird safety are included in the newest version of LEED v3 (2009) as a part of the Innovation and Design (ID) category. Also in some design categories, LEED points may fulfill bird-safety needs at the same time as they fill needs for sustainability and efficiency in other categories. Currently, LEED v4 offers a pilot “bird credit” for those who design and build in a bird-friendly manner.

Have you thought why stone has been largely overlooked by the green building movement, while some products made of recycled plastic are regarded green??!!!

Stone is one of the earliest building materials. It is surprising that stone almost requires no special manufacturing processes and is so durable that stone structures built thousands of years ago are still used today!! (Very few contemporary “green” products may act the same in this case). Besides from that, stone has all the attributes of a green product. It requires almost no chemicals to produce or maintain, it emits no VOCs or hazardous airborne pollutants, and it is water-resistant. In areas with large temperature fluctuations, stone can play the role of a thermal mass. Also some stone even has good solar reflectance. Concerning biophilia concept, as buildings that connect people with nature, it is fair to mention the universal attraction of natural materials like stone. The truth is that stone is most natural material used by human being in the first place to accommodate our ancestors.

A life-cycle assessment (LCA) of granite and limestone claddings has shown that granite cladding compared to brick and mortar, precast concrete, and aluminum had the least detrimental environmental profile, followed by limestone, then brick (a virtual tie), and aluminum. In case of embodied carbon, sandstone, granite, and marble have lower amount than brick, timber, and steel (University of Bath’s ICE).

By comparing stone quarrying to a modest forestry operation, we can understand that the deteriorating habitat impacts are much less than logging and milling wood. Even the amount of site disturbance and soil and habitat loss from forestry operations far exceeds that of quarrying.

Stones that have not been crushed, called dimension stone, can be used as flooring, exterior cladding, solid surfaces, and interior walls, as well as for landscaping and many other applications. Moreover, the crushed stone can also be used in many other industries (concrete, asphalt, landscape, etc.) and this reduces its leftover.

Of the estimated 1.88 million tons of dimension stone produced in the U.S. in 2011, approximately 43% were used by the building industry. (For comparison, this figure is about 20% out of 95.6 million tons of total produced raw steel). Roughly half of the total U.S. stone market is imported from Brazil, China, India, Italy, and some other countries.

Stone Types and Uses

The primary types of dimension stone sold today are granite, limestone, marble, slate, and sandstone. (There are many others, including basalt, soapstone, and quartzite, etc.)

 Different quarries have different looks. Therefore, for designers and architects that search for a specific stone color or type, purchasing locally can be very difficult. Hence, the route that stone takes from processing to site can vary from a few miles to thousands of miles! Moreover, there are some stones that are imported from Brazil or another country and sent to Italy or China for processing before being sent to the U.S. Even stone quarried in the U.S. is regularly sent oversees for processing and then sent back to the U.S. This obviously wasteful practice is due to lower overseas labor costs. For sure, transporting stone from quarry to jobsite does have a negative environmental impact due to the need for heavy equipment and trucks transportation. A study of embodied carbon and natural stone shows that transportation is the main contributor of embodied carbon in stone. However, by considering the long service life of stone and its durability, those transportation impacts may not be quite as significant (in a 100-plus-year lifespan).

A major problem involved with stone is that tracking it from an extraction quarry to its final market can be nearly impossible since just like a commodity, both imported and domestic stone are often sent across the globe and may be processed elsewhere. This makes third party verification system unable to properly judge about some related issues.

There is a misunderstanding problem with stone quarrying. In fact, many people don’t distinguish between quarrying and mining. In mining a lot more material is taken out of mines than in quarrying. For example, in order to produce 1 pound copper, about 143 pounds of rock is needed. Furthermore, stone comes from rock which is at the surface and even at the end of a quarry’s production; the obtained area might be usable land in some cases (i.e. proper for lakes).

The point is although stone is not the greenest material or a complete one; it is close to some best materials that are considered sustainable. Most of the problems of applying it in construction industry are manageable. Therefore, it is essential to increase its valuable functionality in common belief by conducting some more well-organized researches in this case.

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