Lights Out, Flights Out

As the weather starts to warm up, we all can’t wait for spring to come. Soon enough, the world will turn green and the birds will be singing. Whether or not we actually realize it, hearing the birds sing is a core part of why we enjoy being outside. A 2020 study found that a higher diversity of birdsong was correlated with an increase in the restorative effect that nature has among hikers. Not only is it beneficial to have birds here to eat insects and pollinate our plants, but they also contribute to our enjoyment of the outdoors. These songs that we love to hear have quite the backstory, however. 

Some of the birds we see on campus, such as Black-capped Chickadees or American Robins, live here year-round. Many more spend their winters in Central and South America, though. The Wood Thrush, for example, is a common bird you’ll hear up in Colgate’s forest in the summertime, and this bird flies thousands of miles in a matter of days to and from Central America. This amazing bird even flies over the entire Gulf of Mexico in one night, the Cornell Lab of Ornithology reports. Obviously, this can be quite a dangerous journey. These birds migrate at night in order to minimize some of the risks. Predators aren’t out at night, and flying together gives the birds safety in numbers. However, there’s another less natural risk making migration even more dangerous: buildings. 

I’m sure many of us have seen a bird fly into a window or hit a car windshield, but you might not know that bird-building collisions kill somewhere between 100 million and 1 billion birds per year in the United States, and a significant number of these deaths happen during migration. Indeed, this is the second biggest driver of bird mortality after feral and free-ranging pet cats, a 2014 study concluded. When walking around cities during spring and fall migrations, it can sadly be quite easy to find a bird on the ground, either stunned or dead. Even at Colgate, at least a few birds die every year from collisions with buildings like the Trudy Fitness Center. This is especially concerning for Colgate because our woods are actually something of a haven for migratory birds. According to eBird, over 100 different species of birds have actually been identified at Colgate between Taylor Lake, campus and trails up the hill. There is hope for birds, however, because there are ways of reducing collisions with buildings at Colgate and elsewhere. 

Birds are attracted to buildings during their nocturnal migrations because of light the buildings emit. Birds use the moon and stars to help navigate, so artificial light from buildings confuse them. Many species of birds fly quite low in migration, and especially on nights with poor visibility, a light from a building can look a lot like the moon. How can we stop collisions then? Just turn off the lights. In fact, the Audubon Society has a national program that urges cities to do just this. Many cities, such as Detroit or Chicago, that are on key migratory flyways, participate by shutting off some lights on key nights where large numbers of birds will be flying overhead. We can also predict when and where birds are migrating with a tool called BirdCast that uses weather radars to track the “clouds” of birds as they fly, so we can know exactly when to make sure that our lights are shut off. 

Shutting off more lights at night has many other benefits, such as reducing light pollution and saving energy. As an institution that prides itself on being carbon neutral, I think we should continue to improve our practices in sustainability. There’s certainly more that we can all do to help the environment. If you ever come across a bird that has collided with a window, you can be the one to save it. For instance, if you find a bird that appears to be severely injured after a collision, place it in a shoebox with holes poked for air, and let it be without giving it food or water. If the bird doesn’t recover after fifteen minutes, you should call your local wildlife rehabilitator. If you are interested in learning more about this phenomenon and want to help prevent it, you can read Cornell Lab of Ornithology publications.

Next time you’re outside and hear the birds singing, don’t forget the journey they might have taken to get there and think about how you might be able to make that migration a little easier. Keeping our lights on all night is certainly not for the birds.