PHILADELPHIA (WPVI) -- Philadelphia's skyline is proving deadly for migrating birds with hundreds of them discovered along Center City sidewalks recently.
"Just looking at all these little dead bodies is like looking at babies that are lying there about to die and it really affects you," Keith Russell of Audubon Pennsylvania.
Russell said the mass casualty happened October 2. He says it was a perfect storm of weather conditions that first led the birds into danger. They were attracted to the lights in the skyscrapers but unaware the glass would stop their path.
"We expected to have a large migration but we did not expect birds to crash into buildings in the numbers that they did," said Russell.
Russell said birds collide with buildings on a daily basis and especially during migration season, but not on this scale.
His team collected at least 400 of the mostly songbirds, but suspects there are hundreds or thousands more that were injured or that died.
Russell said the last time something on this scale happened was in 1948 when flock of birds slammed into the PSFS building.
"We would like to not see this ever again, but it does happen from time to time and it's hard to predict. The conditions just happened to be right and the birds just happened to be there and everything lined up for something like this to happen," said Russell.
Wildlife experts said a simple solution may help to stop or decrease events like this.
"If the people who owned or managed these buildings downtown would turn the lights off, and the vanity lighting off at night, they wouldn't be seen, but the birds wouldn't see the buildings so much and they would pass by," said Russell.
It's a heartbreaking scene but brings awareness to the problem and Russell hopes it's a teachable moment about the importance of nature.
"If we lose our birds, they are sort of the immune system of nature and if they are not there eating insects and controlling disease and doing other things, we are going to have calamities," said Russell.
All the birds found will be donated to the Academy of Natural Sciences.
Experts say other ways to prevent something like this from happening are to close blinds at night or use green or blue lights.
Hundreds of migratory birds found dead after flying into Center City buildings