Amazing 40-year study finds bird deaths cut dramatically by turning off lights at night

Source: The Hill | June 8, 2021 | Jenna Romaine

“I was really blown away by the sheer magnitude of the influence that building lights may have on birds that we detected,” the study’s lead author said.

What if you could save the lives of birds with the flick of a switch? Well, according to a new study, you can. 

Scientists discovered over the course of 40 years that during nights when the lights in a large Chicago building were off and the windows were darkened, there were11 times fewer bird collisions during the spring migration, and six times fewer bird collisions during the autumn migration, than when the lights were on. The study was published in the latest issue of the journal Proceedings of the National Academy of Sciences.

“At the time I was only recently hired by the Field Museum. I remember having a casual conversation with somebody who mentioned birds sometimes fly into the windows of this building. I was curious. I thought to myself: I work in the museum and things are dying out there, so why not make use of out of them?” David Willard, the collections manager emeritus of the Field Museum in Chicago, told the Guardian of the 1978 conversation that spurred the study.


Willard began to gather the dead birds, bringing them to the museum so he could record them in a ledger of the incidents. It was 20 years before he recognized a pattern in the deaths – Willard would find fewer dead birds the morning after the lights had been off in the building the previous night – that lead  him to begin tracking the lighting.

Willard eventually teamed up with Benjamin Van Doren, a postdoctoral associate at the Cornell Lab of Ornithology, who became the lead author of the paper. Van Doren combined the information from Willard’s ledger with data on bird migration, weather conditions, and radar records, building a statistical model.

The model projected that turning off the lights during migration seasons at the building could lead to a 60 percent reduction in bird fatalities.


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