Flying By Night

Twice a year, millions of birds migrate right over our heads. From about April 1 to May 31 and then again from about August 15 to November 15, birds wing their way from their winter homes to their northern breeding grounds and back again. You might not see all of those epic flights because many birds migrate at night. This is true for many of the birds we love most, including many thrushes, sparrows, wrens, and orioles. They have good reasons to fly by night. It lets them avoid predators and take advantage of calmer air.

But it means they face increased dangers from light pollution.

You might have guessed that I’m a bird lover. To me, it’s obvious we should protect birds. They eat tons of insects like mosquitoes, spread seeds, pollinate flowers, and help control the rodent pollution.  All for free! Plus they raise my spirits and provide joy. What’s not to love?

If you’re like me and thrill at seeing a bald eagle or hearing the first oriole of spring, consider dimming your nighttime lights for birds. Research shows excess light at night disrupts bird migrations, throwing them off course, causing them to mistime their flights, and luring them to fly fatally into buildings. On just one infamous night in October 2020, poor weather conditions led to over 1,000 birds dying after striking lit-up buildings in Philadelphia.

To help, shut blinds after dark and use the principles of responsible lighting for any outdoor lights.  If you want to know when the most birds are flying over Pennsylvania, BirdCast from the Cornell Lab of Ornithology shows you up to three days in advance where migration is heaviest.   That oriole that shows up at your feeder next spring will thank you.