Less Light = More Birds

 

At left, the Chrysler Building about 11 p.m. on Wednesday, Sept. 21, and then an hour later, its lights turned down to aid birds.

Tourists have always flocked to New York City?EUR??,,????'???s bright lights, but starting last month, the city is dimming parts of its skyline to save the lives of migratory birds. The Chrysler Building, Rockefeller Center, the Citigroup Center, the Morgan Stanley Building and the World Financial Center are among the high-profile high-rises that have agreed to requests from the city and the Audubon Society to dim or turn off nonessential lighting at midnight.

Thus the city’s skyscrapers will defer to nature at least twice a year: by dimming their lights in September and October, during the peak of the fall migratory season, and again in April and May, during the peak of the spring migratory season.

The combination of glass, tall buildings and bright light is extremely dangerous for birds, according to Daniel Klem, an ornithologist at Muhlenberg College in Allentown, Pa. He says that a conservative estimate is that more than 100 million birds die each year from crashing into glass on structures of all types, even houses.

“Here is the bottom line: Birds just don’t see glass,” said Professor Klem. “The animals are not able to recognize glass as a barrier and avoid it.”

And lights, particularly those from skyscrapers, distract migratory birds from the visual cues they receive from the stars and the moon, said Douglas Stotz, a conservation ecologist at the Field Museum in Chicago.

The bright lights of tall city buildings pull the birds off their migratory path and into urban canyons, especially when skies are foggy or overcast. Then the birds either crash into the building’s glass at night because they are attracted to the light, or they circle the buildings until they become exhausted. In the morning, when they try to escape the city, they crash into the glass because they are confused by the reflection of sky.

Unless people look carefully, the dead birds can be hard to spot because many of them are small songbirds.

“They would be swept up by custodial staff,” said Adrian Benepe, the New York City parks commissioner. “I’ve often seen them on the streets, and wondered, ‘Why is this little songbird dead on the street?’ ”

Since 1997, Audubon Society volunteers have collected more than 4,000 dead birds of 100 different species at just a handful of buildings in Midtown and Lower Manhattan.

Toronto began a program to dim its lights in 1993, and Chicago started a voluntary program in 1999 that now includes 100 buildings. In Chicago, the Field Museum found an 80 percent reduction in bird deaths when lights were turned off during a five-year study on a single Chicago Building, McCormick Place. “When the lights are on, you get these big bird kills, and when they aren’t, you don’t,” said Judy Pollock, director of bird conservation for the Audubon Society in Chicago.

Even with a dimmed skyline, the problem of birds crashing into glass remains. Environmental groups are working with the construction industry to come up with glass that can be seen by birds, potentially by giving the glass a UV coating.

Of the city’s landmark buildings, the Empire State Building has long been aware of migratory bird problems. For at least 25 years, the building has turned off its decorative lights when large numbers of birds are observed flying around the top of the building during migration season. The circling birds are particularly common during foggy or overcast nights, said Lydia Ruth, a spokeswoman for the building.

Employees from the observatory will call down to the building engineers to tell them to shut off the lights. “We don’t want to take any chances, and we don’t want to cause any bird death,” Ms. Ruth said. “But we have people call the next day, ‘Why did you turn the lights out early?’ You can’t keep everybody happy.”

Source: New York Times