During this weekend's 9/11 Tribute in Lights display, an estimated 10,000 migrating birds became attracted to the lights, trapping themselves inside the beams and wasting precious fat resources needed for migration south. The city's skyscrapers have already agreed to dim their lights to avoid confusing our avian friends, but could Tribute in Lights pose even more of a danger to the birds?

Well, it depends. New York City Audubon has been monitoring the project with the Municipal Art Society to make sure no birds are harmed. And though this year they were forced to shut the lights off for half an hour, Audubon Executive Director Glenn Phillips says it was a rare case. He writes:

We monitor Tribute in Lights and have arranged to have the lights shut off (rather than opposing the project outright) because many times, one night is not significant. Under certain conditions, however, huge numbers of birds move on a single night, and when that happens, obstructions like the Tribute in Light have the potential to cause significant impacts. This year weather conditions in late August and early September were not good for migration—largely as result of Hurricane Earl—creating a backlog of migrants waiting for the right weather. Conditions on September 11 were such that perhaps as much as 20% of the populations of some species were in the air over New York City that night.

John Rowden, the Citizen Science Manager at NYC Audubon, added, "not every night during migration is equal and circumstances combined to make Saturday night an epic (perhaps the epic) migration event for this year." But as one Animal Planet commenter put it, "a better way to remember the fallen of this day would be a method which did not injure something else in the process. im sure there were birders in those towers on that day, and im sure they would not want their memorial contributing to the this problem, i know i wouldnt..." So, should the city find a more bird-friendly tribute, or are the flight patterns of a few geese not important compared to a night of remembrance and honor?