09/28/2026
Each spring and fall, about five million birds (of 250 bird species) migrate through Chicago. These birds are often attracted to building lights and lighted glass areas, sometimes with fatal outcomes. While lights can distract birds from their migration paths, bird fatalities are more directly caused by the amount of energy they waste flying around and calling out in confusion. The exhaustion can leave them vulnerable to other urban threats.
Good light reduction practices significantly lower fatalities. Multi-story buildings can save many birds by turning off decorative lighting from 11 PM until daylight each day from March 15 to June 15 for spring migration, and again from August 15 to November 15 for fall migration. Tenants are also encouraged to turn off lights or draw blinds during these periods.
What You Can Do to Help
• Turn off exterior decorative lighting, including lights on antennas, logos, clocks, and other displays or illuminations.
• Use timers effectively to ensure light is only used when needed.
• Install motion-sensitive lighting.
• Use lower-intensity lighting where possible.
• In outside public areas where light is needed for public safety, avoid “light trespass” by using light fixtures that direct the light down where it is needed, instead of horizontally and/or upward.
• Use desk lamps or task lighting for security desks/work stations rather than overhead lights.
• Use “zone capable” interior lighting systems that allow selected rather than all areas of an interior space to be illuminated.
• Draw curtains or blinds to reduce any light escaping.
