How Turning Lights Out Helps Birds

Lights Out Colorado – How Turning Lights Out Helps Birds

Yellow-rumped Warbler. Photo: Kyle Horton
Yellow-rumped Warbler. Photo: Kyle Horton

Turning lights out a few weeks each year is a simple action we can all take to help birds migrating through, to, and out of our city. Bird populations in North America have declined by 29% (3 billion birds) since 1970, and birds need all the help they can get. Birds are a vital part of our health, economy, agriculture, and environment – from the homebound resident watching birds in their backyard, to the serious birder spending dollars traveling to and around Colorado, to the farmer whose crops are protected from insect infestations. We should do all we can to ensure birds survive and thrive.

Lights Out Colorado

Denver Audubon is partnering with the National Audubon Society and the International Dark-sky Association to launch Lights Out Colorado. This is a new program that aims to help save millions of birds as they begin their spring migrations to and through Colorado at night April-May and August-September.

On the night of April 22, 2021 about 380 thousand migratory birds are predicted to fly over Colorado, according to CSU Aeroeco Lab. “The vast majority (80%) of birds in North America migrate at night, making it imperative to limit artificial light pollution for the conservation of migratory birds,” according to Dr. Kyle Horton, assistant professor at Colorado State University.

Lights Out Colorado provides two simple steps you can take to have a big impact on birds:

  • Shield outdoor lights to prevent light from being emitted upwards.
  • Turn off lights by midnight during bird migration seasons (April-May and August-September).

Learn how to help birds in your community – visit the Lights Out Colorado website, where you can pledge to help migratory birds and encourage your local government to take action.

Image: Colorado State University Aeroecolab
Image: Colorado State University Aeroecolab
Photo: International Dark-sky Association

In addition to helping birds, these efforts reduce energy usage, save money, and can improve safety. Shielded lighting creates safer conditions for humans, reducing the glare that prevents our eyes from seeing into the shadows.

Denver Audubon also supports Lights Out Denver – an initiative of the City and County of Denver officially recognized on the list of national Lights Out projects. Part of Denver’s commitment as an Urban Bird Treaty City, this program aims to help local businesses save energy, money, and migratory birds by promoting bird-safe buildings and reducing nighttime lighting. Lights Out Denver volunteers survey downtown Denver every spring and fall to document bird window collisions. You can see those results at the new Lights Out Denver Collision Mapper.

Image: the National Audubon Society and the International Dark-sky Association.
Image: the National Audubon Society and the International Dark-sky Association.

Why turning lights out helps birds

The majority of nocturnal migrants pass through Colorado spaces and skies from April through May and August through October.

For nocturnal migrants, skyglow – the brightening of the night sky over inhabited areas – can attract and disorient birds during their nighttime travels. This disorientation can cause bird fatalities or lower survivorship and reproductive ability as these birds expend already limited energy resources circling and calling out in confusion. The exhaustion can leave them vulnerable to other urban threats, including predators.

How can I help?

There are a variety of ways that individuals can help birds during their night migrations, and all year-long. This includes turning off outdoor lighting during key migration periods (April-May; September-October) and adjusting necessary outdoor lighting to minimize their harm.

Specific actions you can take for exterior lighting:

  • Turn off exterior decorative lighting
  • Ensure your outdoor lights aim down and are well shielded
  • Use reflective paints or self-illuminous markers for sign/curbs/steps instead of lights
  • Reduce atrium lighting wherever possible
  • Install automatic motion sensors/controls and dimmers
  • Choose warm bulbs (3,000 Kelvins or under) when converting outdoor lights to LED
  • Determine the necessity for new lighting (quality/quantity)

Specific actions you can take for interior lighting:

  • Turn off interior lighting especially on higher stories
  • Use direct lighting (i.e. lamps) for workers staying late or pull window coverings
  • Install automatic motion sensors/controls and dimmers

Finally, please share this information with family, friends, local businesses, and governments. Together we can build caring, bird friendly communities.

Lark Buntings by Maikel Wise
Lark Buntings by Maikel Wise

Track Bird Migration Forecasts

You can view live bird migration maps and access local bird migration alerts and three day forecasts.

The BirdCast project is a joint effort by The Cornell Lab of Ornithology, Colorado State University, and UMass Amherst. BirdCast applies weather surveillance radar to gather information on the numbers, flight directions, speeds and altitudes of birds aloft in order to expand the understanding of migratory bird movement. BirdCast’s migration forecast maps show predicted nocturnal migration 3 hours after local sunset and are updated every 6 hours. Colorado State University’s Aeroecolab is affiliated with BirdCast (and Cornell and U Mass Amherst) and is part of CSU’s Department of Fish, Wildlife, and Conservation Biology.