NEW YORK (CBSNewYork) -- Flocks of birds migrating through New York City are faced with the threat of colliding with glass skyscrapers and now a popular tourist spot has become a new trouble spot.
On Thursday, CBS2's Jenna DeAngelis spoke to bird advocates who are hoping raising concerns will help change take flight.
Calista McRae of Brooklyn picked up a helpless bird on the sidewalk near Brookfield Place in Battery Park City.
"I believe it's a female common yellow throat that probably collided with the skybridge right behind me," McRae said.
McRae explained how a simple skybridge -- or glass building -- can be a death trap for a migrating bird.
"That's really confusing to birds. They look through it and they think they see sky," McRae said.
McRae and Melissa Breyer are volunteers with New York City Audubon's Project Safe Flight, which helps rescue injured birds and documents which buildings pose a threat.
"Hundreds of thousands of birds die a year in New York City from this," said Breyer, of Williamsburg, Brooklyn.
They recently discovered a new area of concern -- the pedestrian walkway at Liberty Park on the World Trade Center campus.
CBS2 saw one injured bird that was one of several McRae found on Thursday morning, alone.
The women believe while the birds are flying through the park, trying to get to the trees, they crash into the glass railing not realizing its there because you can see right through it.
"Most are dead. The ones that are stunned often have wing fractures or chipped beaks and they almost all have head trauma," McRae said.
The Port Authority, which runs the park built in 2016, said it's looking into the situation.
But this is part of a nationwide problem. Millions of birds are killed each year in collisions with glass, including up to 230,000 in New York City, and the New York City Audubon Society says change is needed.
"There is a law in New York City that went into effect this year which requires new construction to use bird-friendly materials, but we still need to convince all of the existing buildings to retrofit and put mitigation in place," said Kaitlyn Parkins, the senior conservation biologist for New York City Audubon.
She said Javits Center was once a trouble spot, but it has since been retrofitted with less reflective glass.
"Also has a ceramic dot pattern in it, which birds perceive as solid barrier, and so collisions were reduced at the Javits Center by about 90%," Parkins said.
Bird lovers are hoping for change, too, to help keep an important part of our ecosystem soaring.
The Audubon Society said this happens most during the spring and fall migration period. There were more than 1,200 stunned or dead birds found last fall in the World Trade Center area.
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