11 September 1948:
Swarms of birds crashed into the Empire State Building early on the morning of September 11th, before plummeting to the street. For more than two hours, the birds dropped to the sidewalks and street in 34th and 33rd Streets and along 5th Avenue. Many of the tiny birds that survived the fall were run over by vehicles. Pedestrians, moved by the plight of the birds, tried to revive some of them on the spot, while others headed home with the creatures, hoping to feed them. Not only was the intermittent plop of the birds disturbing, but particularly weird was the shrill chirping of many injured birds that dropped to setbacks or ledges.

Fog Is Blamed as Birds Die Hitting Empire State Building”, in The New York Times (12 September 1948).

11 September 2010:

On the evening of the ninth anniversary of 9/11, the twin columns of light projected as a memorial over the World Trade Center site became a source
of mystery. Illuminated in the beams were thousands of small white objects, sparkling and spiraling, unlike anything seen before. From beneath, it was at times like gazing into a snowstorm. It was hard not to think of souls. Those unidentified objects have now been identified as birds, pulled from their migratory path and bedazzled by the light in a perfect, poignant storm of
avian disorientation.

Keim, B., “9 / 11 Memorial Lights Trap Thousands of Birds”, in Wired (14 September 2010).
Accessed 22 November 2010: www.wired.com / wiredscience / 2010/09 / tribute-in- light-birds /