Christmas lighting may not be so cheery for wildlife – St George News


Undated photo of a public display of Christmas tree lights, Oslo, Norway | Photo courtesy of Utah State Extension, St. George News

FEATURE – The holidays are here and the festive lights are shining bright. Although this lighting tradition brings joy to many, it can also be considered a source of light pollution.

Giant illuminated Santa Claus seen on Main Street in downtown St. George, Utah. December 22, 2020 | Photo by Chris Reed, St. George News

The International Dark Sky Association coined the term “light pollution” to define excessive or unnatural nighttime illumination. The term is applied to any adverse effect of artificial light, including sky brightness, glare, light trespassing, light clutter, and energy waste. Additionally, light pollution can affect astronomers and scientists, wildlife migrations and activity, and has been linked to human health problems.

Migratory birds that use the moon and stars to navigate may be attracted to beams of light from tall buildings, towers, lighthouses, oil rigs, etc., disorienting them and leading to more accidents. Also, nocturnal predators have the advantage of seeing a larger area, and their prey must seek darkness and spend more time hiding and less time on daily activities.

A recent study published in “Human-Wildlife Interactions” explains the effects of Christmas lighting on the environment during regular periods of darkness. Wildlife students at Texas A&M University in Kingsville reported that Christmas lights used to decorate the university campus were a seasonal source of light pollution that contributed to an increased rate of predation by native eastern fox squirrels. Eastern fox squirrels exhibited normal day/night behaviors year-round, but extended their foraging behavior nearly four hours after sunset with the addition of Christmas lights. The students documented that the monthly mortality of squirrels increased sevenfold with the addition of Christmas lights, possibly due to the extension of their feeding time.

File photo of a home in Washington decorated for the holidays, November 30, 2019 | Photo by Chris Reed, St. George News

Additional studies suggest that the public is often unaware that bright lights can negatively alter wildlife behavior. Because of this, the students recommended educating the public on how light pollution affects wildlife and the environment. Consider these suggestions:

  • Check to see if there is a “Lights Out” program in your community. Some cities have adopted a schedule in which the interior and exterior lighting of tall buildings is dimmed or turned off during bird migration. Bare bulbs or upward pointing lights are replaced with hooded lamps that only shine downward. If the lights cannot be turned off, a flat lens and a reduced number of lights and intensity are used.
  • Turn off unnecessary outdoor lights at night and turn off Christmas lights when you go to bed.
  • Dim the light by using fewer exterior lights or by using colored lights instead of clear white bulbs. Research shows that colored lights are less attractive to wildlife and may lessen the negative effects on them.
  • Consider your relationship with the environment and how your actions affect it.
  • Carefully consider decisions related to cost, safety, health, and environmental well-being when planning and using outdoor lighting.

To access the full research report, visit

Written by TERRY MESSMER, Utah State University Extension wildlife specialist, 435-797-3396.

Copyright St. George News, LLC, 2022, all rights reserved.

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