Large Bird Kill at Cross Spawns Change, Research

by Kevin Cummings, Messenger Staff Writer
On the night of Sept. 26 and in the early morning of Sept. 27, more than 130 birds died after slamming into the Sewanee War Memorial Cross and nearby trees, and dozens of birds died in a similar event in Grundy County.
Officials said a cold front moved through the area that night with low cloud cover, which forced the nocturnal migrating birds to fly lower than usual. The birds became attracted to and disoriented by the lights and flew in circles until they collided with structures and trees. Researchers theorize that migrating birds use the earth’s magnetic field to help navigate, and artificial lighting confuses them, an event called positive phototaxis.
“This is a fairly common problem and one of the many challenges birds face during migration,” said David Hanni, bird conservation coordinator for the Tennessee Wildlife Resources Agency.
Sewanee is consulting with Cornell University’s Laboratory of Ornithology, and officials are in the process of getting federal permits to ship the birds to Cornell for further research.
“They will want to confirm the cause of death, then look for similarities between this event and others around the country,” said David Haskell, resident ornithologist and Sewanee biology professor. “We still know very little about nighttime bird migration, so this collection will add to that body of knowledge.”
Researchers will include the specimens in the long-term archive of North American birds at Cornell, Haskell added, where they will use the birds for various studies like pesticide levels, taxonomy and examination of diet.
Nate Wilson, Sewanee’s Domain manager, said Physical Plant Services quickly changed the two lights at the cross to lower wattage bulbs, from 2,000-watt bulbs to 400-watt bulbs.
“It’s an incomplete solution, but something we could do immediately. We need to think comprehensively,” Wilson said.
Potentially adding a timer, which would allow the birds to break away from the lights, is a possible solution, Wilson added.
Approximately 80 birds died the same night at Beersheba Springs Assembly, a United Methodist retreat center about 45 minutes from Sewanee. A Grundy County Wildlife Resources officer took some of birds for autopsy.
“We are not sure what caused this bird kill and until we know anything further we are assuming that the birds were killed in the same way as those at Sewanee,” Assembly director Dickie Hinton said on Oct. 4.
There were also reports of numerous bird deaths at the Sewanee Inn that night, but Michael Beutel, the Inn’s general manager, said a maintenance worker found only one dead bird.
There was an additional report of a bird kill in Van Buren County, although Hanni and Greg Wilson, Van Buren County mayor, said they were not aware of an incident.
Haskell lauded the University of the South for its rapid response at the Cross and said the issue needs further discussion.
“Lowering wattage and adding a timer will definitely help,” he said. “More broadly, this event underscores the need to think carefully about how and why we use spotlights at night.”
The approximately 55-foot-tall Memorial Cross, erected in 1922 at the end of Tennessee Ave., honors local students and residents who served in war. The University installed lights at the Cross in 1927, with those first lights funded via the sale of the Sewanee Cookbook, according to records at the University Archives and Special Collections.
Haskell, who has worked in Sewanee for 20 years, said he has seen other bird deaths at the cross on a smaller scale, usually six or fewer, after foggy nights.
“The raccoons clean up the site very quickly, so I see these only right after dawn,” he said. “The large plate-glass back window of McClurg Hall has killed many birds over the years, especially hawks and hummingbirds. I assume they see the glass as sky and just keep flying.”
Wilson said on Oct. 3 there haven’t been any other bird deaths at the Cross since the night of Sept. 26. The dead birds included a variety of species, such as the Scarlet Tanager, Common Nighthawk, Yellow-billed Cuckoo, American Redstart, Pied-billed Grebe, Wood Thrush, Gray Catbird, Ovenbird, Northern Waterthrush and Bobolink, researchers said.
Millions of birds have died since the advent of artificial lighting, with one of the largest events in the U.S. related to a fireworks display on New Year’s Eve 2010 in Beebe, Ark., which resulted in the death of about 5,000 birds, according to the National Audubon Society. The Tribute in Light, the memorial for 9/11 victims in New York, has seen issues with thousands of birds getting confused in the light beams. Volunteers there shut the lights off for short intervals if they see trapped birds.
Haskell noted individuals can help prevent bird deaths by monitoring windows at home. If the windows are often struck by birds, he said people can consider strategies advised by Cornell at <allaboutbirds.org/why-birds-hit-windows-and-how-you-can-help-prevent-it>.