But what about the birds that are rescued and brought to wildlife rehabilitators? In August 2021, Ar Kornreich, a Fordham biology Ph.D. student who is working on a dissertation about catbirds, began investigating how many of those birds also succumb. 

“I knew not all birds die immediately, and I wondered if there had been any research on birds that make it for a while before they die,” said Kornreich, who uses they/their/them pronouns.

“It just seemed like a no-brainer that states should have that info.”

In fact, Kornreich discovered that there is no one place where one can easily access this information. So they filed Freedom of Information Act (FOIA) requests with eight state agencies tasked with regulating the wildlife rehabilitators. They requested records regarding avian building collision cases between 2016 and 2021. Eventually, they received responses from six states, Washington D.C., and several privately run rehabilitators.

Findings

Kornreich and their co-authors published their results on Aug. 7 in the paper “Rehabilitation outcomes of bird-building collision victims in the Northeastern United States” in the journal PLOS ONE.

They and their co-authors found that of the 3,033 birds that were rescued in these areas, about 60% didn’t ultimately make it: 974 died during treatment, while 861 had to be euthanized. The data also revealed that birds were injured more often during the autumn months, and concussions were the most common injury. 

These numbers—and the estimates that can be drawn from them—suggest that bird collision deaths far exceed one billion each year in the U.S., the paper says.

“There’s a huge blind spot in those birds that hit buildings and survive, at least for a little while, and looking at rehabilitation data can help remove that blind spot and help us make more informed decisions about conservation and preventing window collisions for bird populations,” Kornreich said. 

There are gaps in the data. The State of New York refused to release the data for all 62 counties in the state, for instance, so Kornreich limited their request to 10 counties in the New York metropolitan region. 

The data also came in formats as varied as PDF files and handwritten pages that needed to be painstakingly transcribed. What had initially seemed like an easy project that could be done while the world was on lockdown during the pandemic turned out to be anything but, said Kornreich. 

“It was funny; I had to buy the state of Pennsylvania a USB drive so that they could send me all of their data,” they said, laughing.

“I completely underestimated how much work it was going to be.”

Working with a Fordham Grad

To help make sense of the data, Kornreich partnered with Mason Youngblood, a postdoctoral fellow in the Institute for Advanced Computational Science at Stony Brook University. Dustin Partridge, Ph.D., GSAS ‘2020, from the NYC Bird Alliance, and Kaitlyn Parkins, GSAS ’15, from the American Bird Conservancy, served as advisors and co-authored the paper.

Kornreich said they’re hopeful that this research will help wildlife rehabilitation improve their desire and ability to share information. Just as hospital administrators share data on how patients fare after entering their doors, so too should wildlife rehabbers be open, they said.

“There is a very active community of rehabbers who are constantly swapping information and doing their best to make sure that their triage is data-driven and they’re using the most successful treatments,” they said. 

“But sometimes the rehab, scientific, and policy community’s transmission of information isn’t the most efficient. Some people in the scientific community look down on rehabbers and say they’re not really making a statistically significant difference, but I think that they are. They’re on the front lines of this crisis, so it is important to get their data and their viewpoints into this conversation.”

At 292,000 square feet, the Jacob Javits Center’s green roof is the second largest in the nation. The center is also bird-friendly; tiny ceramic dots cover the windows, to make them visible to the birds and prevent collisions. From above, the building is an island of green where there once was no green space at all.

On the roof one can immediately see how the birds have taken to the space, as dozens of seagulls hover. A few of the gulls have begun to lay eggs in the roof’s sedum succulents, as have Canada geese and even small falcons have begun using the roof for hunting. Surveying the scene, J. Alan Clark, PhD, associate professor of biology and coordinator of Fordham’s conservation biology program, gestured to the city’s skyline.

“Most birds migrate at night and are negatively impacted by the light and noise. You can’t do too much about noise in cities but if we can do something about lighting, that might be a way to make the skies much safer for migrating birds.”

As the New York City Council contemplates an energy-saving bill to reduce lighting used in buildings around town, Clark wants to research how those lights affect bird migration patterns.

Clark began studying the patterns more than seven years ago in locations that ranged from Central Park to the Bronx Zoo to a nature reserve in Westchester. Through radar and acoustical recording, Clark’s study tracked how birds navigate through urban landscapes vs. green spaces.

He’s looking expand the study to measure the effects of light by installing radar equipment on the Jacob Javits Convention Center’s massive green roof in midtown Manhattan.

Clark is one of several New York City area researchers that are using the roof for research. Completed two years ago, the green roof is relatively new. Yet birds and their food source, arthropods, are already settling in, he said, and are using the space as an oasis in the densely populated region.

When Clark first came to Fordham in 2007, there was very little data on how birds navigate through urban landscapes. Clark began researching their movements in 2009, using recording devices to listen to the birds—which make very species-specific calls during migration to maintain group cohesion. He noticed that birdcalls were three to twelve times higher over urban areas than over nearby green spaces.

Clark said that migrating birds are attracted to artificial light. Communication towers and lighthouses have always been well-known “death spots.”

“During migration birds are attracted to lit structures where they’ll hit the wires, hit the buildings, hit each other, or fly in circles and drop from exhaustion,” said Clark.

This will be the fifth time Clark has studied the effects of light on migration. In 2012, Clark worked with light sculptor Rafael Lozano-Hemmer at a light installation in Philadelphia where the artist regulated color, brightness, and direction of the lights while Clark monitored bird behavior. This time, the migration study would be taking take place over one of the densest urban environments in the world.

Earlier studies led Clark to speculate that brighter urban areas are more stressful for migrating birds. Using a DeTect avian radar tracking system synched with acoustical recordings, his team determined that the same density of birds were migrating over both urban and green areas “but they were calling more and flying higher over urban areas,” he said.

The Philadelphia research further revealed that the color of the light also made a difference. Red light proved the most attractive to the birds, while blue and green were less so. But when the light was intense and white 75 percent flew in circles or in the wrong direction.

“They were supposed to migrate south, but the white light made them go north or circle in the light,” he said. “The reverse was true in blue and green light.”

Clark’s next step is finding funding to move from pilot level studies to a much larger scale experiment built on the earlier research. DeTect is working on a radar design, the parts of which can fit into the center’s elevators and then be assembled on the roof. Clark said that the Javits management has been an exemplary and willing partner, opening the rooftop to biologists from Fordham and New York City Audubon to study birds, as well as bats and bugs.

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Dustin Partridge is not a city person. The biology doctoral candidate in Fordham’s Graduate School of Arts and Sciences said that no one is more surprised than he that the subject of his dissertation would be so urban focused.

“I never imagined that I’d be studying wildlife on the roofs of New York City,” Partridge said.

His four years of research have revealed that many migratory birds that pass through New York City each year are using the green roofs as the bird-equivalent of boutique hotels: small, somewhat exclusive little crash pads where they can feast on the insects that have also settled there.

Partridge garnered notice in the Jan. 27 issue of  National Wildlife magazine for his “resourceful” research.

As anyone who lives in New York knows, getting rooftop access is not an easy task. Partridge said that the green-roof owners were more than accommodating, but nearby non-green roofs were needed in order to control the study, and these proved much harder to secure.

Partridge had studied birds in Maine before decamping to New York to work as an adviser for an engineering firm. After observing a few endangered bird species, his interest in urban ecology was piqued.

Because New York City is the Atlantic flyway, millions of birds that pass through during fall and spring migration require stopovers to replenish their fat. During the season hundreds of species to land in Central Park en masse, in what has become known as the Central Park Effect.

“The Central Park Effect makes the park super-concentrated, with about 200 species a year–even random birds from Africa,” said Partridge. “It made me curious about smaller spots in the city.”

Partridge said that, in addition to non-green roofs, he studied two types of rooftops: intensive roofs, with a significant depth of soil and well maintained gardens; and extensive roofs, with less soil and succulents that require little soil, maintenance, or water.

“In all I’ve recorded 37 species, and of them 26 were unique to green roofs–the woodcocks and humming birds were very unexpected,” he said, adding that there were plenty of insects and spiders for them to eat and whose presence sparked yet another series of questions for the biologist. “How do they get there? What shapes their community?”

He studied birds and arthropods as an undergraduate and now does research in the laboratory of Dr. Alan Clark, Ph.D., assistant professor of biology. Recently the two of them collaborated on Urban Green Roofs as Migratory and Breeding Bird Habitat, funded by the New York City Audubon Society, Sigma Xi and Fordham.

The data collection, completed last spring, measured the frequency with which migratory birds land on green roofs while passing through the city on their southern route. Using Autonomous Recording Units (ARUs) to measure bird calls, Partridge recorded the amount of bird traffic on four green roofs (in three boroughs) against four traditional roofs of comparable size and elevation located almost directly across the street from each green roof. On average, up to three times more species and four times more birds were found to use the green roofs.

Of course, the data is hardly a surprise, said Partridge. What is surprising, he said, is the amount of benefit that cities and neighborhoods can take from installing more green roofs.

The first is diversity: the roofs attracted species that don’t show up on other rooftops—the raven, peregrine falcon, ruby-throated hummingbird, willow flycatcher, wood thrush, cedar waxwing and others. In an area like New York, which has a certain number of endangered species, these rooftops can only help to support biodiversity.

Secondly, roof greenery itself is not only sustainable but it helps with heating and cooling of the host building, as well as offering a place of refuge for the building occupants.

Thirdly, the roofs can provide additional needed refuge space for birds on the Atlantic Flyway, a migratory route that has increasingly limited habitat for the millions of bird species that use it each spring.

“I love birds and I love arthropods,” said Partridge. “It is my hope that our study will be used to fund more support for green roof installation in New York City. “

Partridge noted that 24 percent of Manhattan is rooftop, and only three percent of the borough is dedicated to natural green space.

“The benefits of green roofing are quite incredible for any city or neighborhood,” he said.

The study data was presented at an October conservation conference at the Museum of Natural History. Partridge took the photos of the green roofs (pictured) in lower Manhattan and in the Bronx (the large green roof is, in fact, the Bronx County Courthouse, said Partridge.)

—Janet Sassi