Tall buildings are causing the death of millions of migratory birds each year, a new study published by Cornell Lab of Ornithology has revealed.
The report, which ranks 125 cities by the level of risk they pose to these birds, says that the bright lights and glazing of skyscrapers lead to deadly collisions and death.
Some of the cities that are highly dangerous to birds are Chicago, which happens to be in one of the most popular migration paths, as well as the dense metropolitan areas of New York City and Los Angeles with their glass skyscrapers.
A 2014 study had roughly estimated that 100 million to one billion birds were killed every year in the US, mainly because of building collisions, and particularly collisions with windows. This number is corroborated by the Smithsonian's migratory bird centre. Migratory birds are attracted to the bright lights of these skyscrapers, drawing them away from their flight path at night.
Yet another study on birds says songbirds in particular are at high risk – these birds get disoriented by the lights of illuminated buildings at night, making them send out flight calls and luring other birds to suffer the same fate.
However, several initiatives have begun in cities to help reduce these avian fatalities. In addition to guides for new buildings and modifications for existing structures, recommendations are provided for using only certain types of glazing to deter birds.
While buildings within 300 feet of an urban bird refuge are hazardous, structures with large uninterrupted glazed segments should be avoided. Preferred glazed facade finishes should be able to reflect ultraviolet light, or use dichroic, fritted and etched glass.
Reducing the lights of buildings in the flight path of these migratory birds is another suggestion as the birds can be attracted to this brightness.