06-03-2010
Buildings for the Birds
Recently, Glenn Phillips, Executive Director of the New York City Audubon Society, lectured on bird-safe buildings, a near and dear subject to the firm, yet one that is off the radar for most architects and developers.
According to Phillips, buildings kill at least 100 million birds annually in the US. In fact, buildings are the second largest contributor to bird deaths after habitat loss. Beyond cruelty to animals, this issue has greater impacts by upsetting the delicate ecological balance because birds contribute to pollination, seed distribution, and insect control. Phillips elaborated that bird mortalities result from complex interrelationships between migratory patterns and corridors, flight height and speed, time of day, biological navigation mechanisms, building height, placement of vegetation, glazing properties, and building lighting strategies.
Birds migrate as far as 14,000 miles from the Arctic to the Caribbean and South America, and many flights are continuous without any refueling stops—for example, Blackpoll Warblers undertake a 72-hour non-stop flight. Flight speeds are not slow; over 90% of migratory species fly between 15-45 mph. The majority fly at heights of 50-2000 feet, well within building height ranges. Given that the east coast—one of the most densely developed regions in the world—is a major migration corridor, the overlay of flight patterns with tall buildings creates a high probability for collisions.
Phillips presented specific case studies of both bird-killing and bird-safe buildings, as well as outlined the key components for minimizing mortality. The key factors contributing to collisions are fourfold: lighting, reflection, transparency and vegetation. Strategies focusing on these four factors have demonstrated significant reduction or elimination of accidents. The simpler strategies relate to lighting—turn lights off during migration periods (11pm-4am,) and avoid red lights as they confuse birds' internal navigation mechanisms. These strategies have yielded major reductions of bird deaths around the Empire State Building. Building owners should be educated in this regard, particularly given the added benefit of energy savings.
Developing proper vegetation strategies is another critical issue for bird safety. Since trees, bushes, and green roofs provide food and shelter, their placement on or near buildings should be done in a manner to minimize reflection in adjacent windows or glazed facades, either by selecting proper glazing, placing sufficient distance between vegetation and glazing or, inversely, at a distance of less than three feet. As well, minimize visibility of interior landscaping and trees as birds will be incited to fly towards them.
Architects have the greatest control in mitigating avian mortality in the design of the building enclosure. Location of glazing and other reflective materials and selecting specific glazing properties can do much to deter birds. The fundamental principle for glazing is to create a perception of mass and visual noise. This can be achieved a number of ways: minimize glazing reflectivity and transparency; use etching, frit, colored, and opaque glass of sufficient density; specify bird safe glazing; create physical barriers such as shading devices; and angle the glazing to reflect the ground or other buildings. Equally important, avoid large expanses of monolithic glass that merge with the sky. Particularly significant is ground floor glazing, where visual noise to deter birds may conflict with retail facility requirements.
Though the issue of bird-safe buildings has yet to enter the vanguard of the building industry, Phillips pointed to recent progress that has garnered awareness. New York City Audubon's 2007 Bird-Safe Building Guidelines provokes designers to take the subject more seriously. As well, LEED 2009 incorporated language discussing bird-safety in several applicable credits. Audubon also is working with the USGBC to develop a LEED Innovation & Design credit on Bird-Safety. More recently, the proposed Federal Quigley Bill would, if passed, require all GSA buildings to incorporate bird-safe building strategies and materials.
In spite of these advancements, Phillips emphasized the need for more research to better define and more accurately quantify which strategies and technologies work most effectively, as well as to more clearly outline the correct analytical approach when beginning a project. We should design our buildings not only to solve the problem of bird-safety, but to test solutions and explore new and innovative approaches. We cannot solve the issue overnight, but bringing it to the foreground of our consciousness as architects and designers is an essential first step.
According to Phillips, buildings kill at least 100 million birds annually in the US. In fact, buildings are the second largest contributor to bird deaths after habitat loss. Beyond cruelty to animals, this issue has greater impacts by upsetting the delicate ecological balance because birds contribute to pollination, seed distribution, and insect control. Phillips elaborated that bird mortalities result from complex interrelationships between migratory patterns and corridors, flight height and speed, time of day, biological navigation mechanisms, building height, placement of vegetation, glazing properties, and building lighting strategies.
Birds migrate as far as 14,000 miles from the Arctic to the Caribbean and South America, and many flights are continuous without any refueling stops—for example, Blackpoll Warblers undertake a 72-hour non-stop flight. Flight speeds are not slow; over 90% of migratory species fly between 15-45 mph. The majority fly at heights of 50-2000 feet, well within building height ranges. Given that the east coast—one of the most densely developed regions in the world—is a major migration corridor, the overlay of flight patterns with tall buildings creates a high probability for collisions.
Phillips presented specific case studies of both bird-killing and bird-safe buildings, as well as outlined the key components for minimizing mortality. The key factors contributing to collisions are fourfold: lighting, reflection, transparency and vegetation. Strategies focusing on these four factors have demonstrated significant reduction or elimination of accidents. The simpler strategies relate to lighting—turn lights off during migration periods (11pm-4am,) and avoid red lights as they confuse birds' internal navigation mechanisms. These strategies have yielded major reductions of bird deaths around the Empire State Building. Building owners should be educated in this regard, particularly given the added benefit of energy savings.
Developing proper vegetation strategies is another critical issue for bird safety. Since trees, bushes, and green roofs provide food and shelter, their placement on or near buildings should be done in a manner to minimize reflection in adjacent windows or glazed facades, either by selecting proper glazing, placing sufficient distance between vegetation and glazing or, inversely, at a distance of less than three feet. As well, minimize visibility of interior landscaping and trees as birds will be incited to fly towards them.
Architects have the greatest control in mitigating avian mortality in the design of the building enclosure. Location of glazing and other reflective materials and selecting specific glazing properties can do much to deter birds. The fundamental principle for glazing is to create a perception of mass and visual noise. This can be achieved a number of ways: minimize glazing reflectivity and transparency; use etching, frit, colored, and opaque glass of sufficient density; specify bird safe glazing; create physical barriers such as shading devices; and angle the glazing to reflect the ground or other buildings. Equally important, avoid large expanses of monolithic glass that merge with the sky. Particularly significant is ground floor glazing, where visual noise to deter birds may conflict with retail facility requirements.
Though the issue of bird-safe buildings has yet to enter the vanguard of the building industry, Phillips pointed to recent progress that has garnered awareness. New York City Audubon's 2007 Bird-Safe Building Guidelines provokes designers to take the subject more seriously. As well, LEED 2009 incorporated language discussing bird-safety in several applicable credits. Audubon also is working with the USGBC to develop a LEED Innovation & Design credit on Bird-Safety. More recently, the proposed Federal Quigley Bill would, if passed, require all GSA buildings to incorporate bird-safe building strategies and materials.
In spite of these advancements, Phillips emphasized the need for more research to better define and more accurately quantify which strategies and technologies work most effectively, as well as to more clearly outline the correct analytical approach when beginning a project. We should design our buildings not only to solve the problem of bird-safety, but to test solutions and explore new and innovative approaches. We cannot solve the issue overnight, but bringing it to the foreground of our consciousness as architects and designers is an essential first step.