More than 10,000 confused birds were trapped by the beams of memorial lights switched on to mark the anniversary of the September 11, 2001 terrorist attacks in New York. Two beams emanating from Manhattan, known as the Tribute of Light, had to be turned off five times to allow the migrating birds to continue on their journey last week. The birds were on their way from Canada to the warmer climate of the Caribbean and South America.
They do not always fly over New York and the last time their migratory path coincided with September 11 was in 2004. The Tribute of Light is turned on by the Municipal Art Society every year on the anniversary of the attacks. Monitors from New York City Audubon, a conservation organisation, observed this year's tribute and alerted organisers to the confused birds.
An Audubon spokesman said that the birds could use up valuable energy needed for their migration while flying around in the lights. He said: "We have a protocol in place in partnership with the Municipal Arts Society in case something happens like it did. There were huge numbers of birds flying through and large numbers did have difficulty navigating out of the beams. The Municipal Arts Society were very supportive of our goals of minimising risk to migratory birds."
The lights were shut off for about 20 minutes each time to allow the birds to clear the area. An estimated 90,000 birds die each year after becoming disorientated by lights and crashing into skyscrapers in New York as they migrate south for the winter. Owners of tower blocks are increasingly switching off or dimming their lights to reduce the risks to birds.