Spring migration of birds returning from their southern wintering grounds takes place every year from roughly April 1 through May 31. From tiny warblers weighing less than an ounce, to hawks and shorebirds, in the billions, they are on the move right now.
The majority of migration takes place at night, allowing birds to land and feed during the day. Because of the night flights, in addition to battling weather and predators, one of the biggest threats to migrating birds is light pollution. They become disoriented by bright artificial lights and attracted to urban centers, causing them to detour, expend more energy and end up in places with less food and more dangers.
Building collision is another major danger. An estimated one billion birds are killed annually from direct collisions with illuminated buildings, towers, and other structures across the country. With 80% of the United States impacted by photo-polluted nights, light pollution of airspace and increased urbanization poses serious threats to birds migrating at night.
Audubon is partnering with USGS Bird Banding Lab, Smithsonian, Georgetown University, the Cornell Lab of Ornithology, and Movebank to bring together tracking data for birds that spend a portion of the year in North America, to better understand when and where migratory birds will be. A national collaboration among Audubon’s Bird-Friendly Communities network and the International Dark Sky Association (IDA) is helping to build and strengthen www.audubon.org/lights-out-program. To date, over 40 cities and several state and regional efforts are underway to turn out the lights during migration.
In our area, the New York City Audubon Society, working with the Lights Out Coalition in 2021, achieved a significant victory with the unanimous passage in the New York City Council of artificial light legislation requiring that all city-owned buildings turn their nonessential outdoor lights off from 11pm to 6am during peak migration periods. But this does not cover vast majority of privately owned buildings which are still attracting and killing birds.
NYC Audubon also monitors the annual 911 memorial lights. The intent of the lights has never been to capture, disorient and kill thousands of songbirds, but it was an unintentional by product of the powerful twin beams of light during fall migration. Audubon volunteers spend the night on adjacent rooftops, monitoring the number of birds pulled into the light beams and the beams are shut down periodically to let the birds continue their journeys.
In your home or office, you can help reduce these risks to migratory birds from artificial light by turning off all exterior floodlights, spotlights, and decorative, vanity, and event lighting during the heights of migration: April 1 through May 31 (spring) and August 15 through November 15 (fall), from 11pm until 6am. Just flick that switch:
1. Turn off exterior floodlights
2. Turn off lights at night in unused spaces
3. Choose shielded lighting that directs lights downward
4. Install automatic motion sensors and controls wherever possible
5. Close curtains and blinds
6. Change the color- white, red, and yellow light attracts birds migrating at night much more than blue or green light
There are several solutions to reducing bird collisions with glass. Birds don’t ‘see’ glass the way we do and may fly into windows and other surfaces that reflect the surrounding landscape or try to fly through glass that appears transparent. Birds need to be shown that the glass isn’t an extension of the outdoors.
1. Create patterns on the outer surface, such as stripes and dots, with stickers on the outer glass surface using commercial products designed for this purpose, or create your own design using craft paper, tape, stickers, paint, and markers designed to be used on glass.
2. Make the glass look solid by completely covering the outer glass surface with paint, perforated vinyl film, or other materials that will make the glass appear opaque. Perforated vinyl film products are available, which create a solid appearance from the outside, but allows views from the inside.
3. Place barriers like screens, netting, or hanging cords in front of the glass. As long as the barriers do not contain open spaces that are larger than 2 x 2 inches, or the hanging cords are spaced no wider than 4 inches apart, they can effectively discourage most birds from trying to fly through them into the glass.
4. Closing blinds or curtains can help discourage birds from flying into windows by creating the appearance of a series of barriers. Closing curtains and shades can also discourage collisions on windows that appear transparent from the outside; however, they are best used on windows where collisions are being caused by the appearance of transparency.
5. Move interior plants away from windows as birds perceive them as habitat and may try to fly towards them.
6. Place bird feeders directly on windows or closer than three feet, or more than 20 feet. This prevents birds from building up enough momentum to harm themselves if startled when near the window, and having time to deviate if far away.