Take-Aways

  • Bright or high color temperature outdoor night lighting threatens bird health and safety
  • The AMA warns that outdoor night lighting with color temperature greater than 3000 K is a danger to people, too
  • Street lights that are no brighter than necessary, and has color temperature less than 3000 K, is safest for birds and people

Streetlights and Wildlife

Tom Jervis, President, Sangre de Cristo Audubon Society


In the 21st century, we are accustomed to think of light as something that happens when you flip a switch.  But as recently as 100 years ago, artificial light was something that limited and dim.  It was not until after the Second World War that the technology to generate vast quantities of electrical energy and transform that into astonishing levels of illumination, among other social benefits, became widespread. With the recent advent of inexpensive and highly efficient light-emitting diode (LED) technology, our capability to bring very high illumination levels took a great leap forward.

Wildlife evolved to live with the natural day-night cycle and seasonal variation in that pattern. Most living things, including humans and many plants, are exquisitely tuned to these circadian rhythms by internal clocks that keep our body processes functioning properly.

Modern LED technology, particularly high color-temperature (blueish) lighting, has created a serious problem for wildlife beyond that already created by our sprawl into areas not previously affected buy our civilization. There are two issues with area lighting such as streetlights. The first is the intensity of illumination and how well it is directed to those places where it is wanted and needed. LED lighting is generally better directed than the commonly used light fixtures of the recent past and it is easier to control to prevent “trespass light” going where it is not needed. Because it is so efficient, however, it is too easy to create a glare problem both for humans and for wildlife if direct and reflected light are too intense.  The second issue with LED lighting has to do with the color temperature of the light. LEDs come in color temperatures from about 1000 K to 10.000 K or more.  The higher the temperature, the more blueish the light is; the lower the temperature the more yellow to red it is. Note that this is independent of the intensity—usually measured in lux (lumens per square foot)—of the illumination.

Macaw. c. Sam Finn

 

For wildlife, particularly birds and insects, the problem is compounded by the color temperature of the lighting. Birds and insects “see” in the ultraviolet (UV) and high-color temperature lights contain significant UV light. Lights of any kind disturb the day-night rhythm that animals expect, but the intense blueish light of high temperature LEDs amplifies the effects.

Wood Duck. c. Sam Finn

Research has shown that blueish light from high color temperature LEDs is particularly disturbing to birds, many of whom migrate at night, navigating by the stars and Moon. They are confused by overly-bright lights, disrupting their migration patterns and causing them to be “trapped’ by these lights until they collapse from exhaustion. Higher levels of light pollution were associated with more species during migration—evidence that light pollution attracts migratory birds to cities across the U.S. Research has also found that cities contained the greatest numbers of migratory bird species during spring and autumn migration.  This is cause for concern, as it shows that the influence of light pollution on migratory behavior is strong[i].

Research in Germany on the Blue Tit, a chickadee-like bird, has demonstrated that artificial lighting results in the males starting to sing earlier in the morning, and that  females start to build their nests earlier in the season. The researchers also documented disruption in the mating behavior of the birds, resulting in more “extra pair” matings[ii].

Insects are also attracted to light, more so by light with a high UV content. Research has shown that populations of insects living near to artificial lights include more predator and scavenger species than populations living in similar, but darker, conditions. This shift can affect the survival rates of different species and have effects on birds and mammals that feed on those species. Interestingly, the effects were seen during the day, as well as at night, so these population shifts are ongoing[iii]. Mammals, many of whom are nocturnal, so bright artificial lighting, particularly high color-temperature LED lighting, is bad for them as well, disrupting their circadian rhythms, their foraging and hunting behaviors, and their ability to avoid predators[iv].

Ruby-crown Kinglet. c Tom Taylor
Ruby-crown Kinglet. c Tom Taylor

 

Finally, the American Medical Association (AMA) issued a rare warning and guidelines on how communities can choose LED streetlights to “minimize potential harmful human health and environmental effects.”[v] The AMA’s statement recommends that outdoor lighting at night, particularly street lighting, should have a color temperature of no greater than 3000 Kelvin (K).

So high levels of lighting, particularly UV-rich LED lights, is bad for animals disrupting the behaviors which evolution has prepared them for life in the world. But at the same time, we need artificial lighting for the protection of public health, safety, and security. Fortunately, there are solutions.  The same technology that produces UV-rich and overly bright lights also makes it possible to make lights at a lower color-temperature with more than adequate intensity for public purposes. In a review of artificial lighting for the National Park Service[vi], the authors concluded that for the particular case of roadway lighting, that “Where light is essential, fixtures should be full cutoff and shielded to minimize glare from any non- road site …. The best overall choice for spectrum is probably yellow (e.g., low-pressure sodium or yellow/amber LED).”

The choice is ours to make.  We can have the social benefits of artificial lighting with minimal disruption of the natural world if we choose the right lighting source. Low color temperature LEDs provide public safety and security and are efficient and low-cost to operate. That is the path we should take.

Dig Deeper!

[1] Cities can help migrating birds on their way by planting more trees and turning lights off at night, <https://theconversation.com/cities-can-help-migrating-birds-on-their-way-by-planting-more-trees-and-turning-lights-off-at-night-152573>.

[2] Artificial night lighting affects dawn song, extra-pair siring success and lay date in songbirds, Bart Kempenaers, Pernilla Borgström, Peter Loës, Emmi Schlicht and Mihai Valcu, Current Biology, 20 1735, 2010.

[3] Street lighting changes the composition of invertebrate communities: Thomas W. Davies, Jonathan Bennie, and Kevin J. Gaston; Biology Letters, Volume 8, Issue 5, 23 May 2010.

[4] Ecological Consequences of Artificial Night Lighting. Catherine Rich & Travis Longcore (eds). 2006. Island Press. Covelo, California. Pages 15-42. http://www.urbanwildlands.org/ecanlbook.html.

[5] http://www.ama-assn.org/ama/pub/news/news/2016/2016-06-14-community-guidance-street-lighting.page.

[6] Artificial Night Lighting and Protected Lands : Ecological Effects and Management Approaches, Travis Longcore and Catherine Rich, Natural Resource Report NPS/NRSS/NSNS/NRR—2017/1493, National Park Service, Fort Collins, Colorado.

“I believe Santa Fe can be a leader in energy conservation as well as protecting our dark skies.”

Santa Fe City Councilor Mike Garcia


Take-aways:

  • There will be public hearings on the light color temperature
  • The false claim that the City was being “forced” by NM DOT to high temperature lighting has been definitively laid to rest. 
  • The false claim that the original Santa Fe proposal met with the IDAs approval has been debunked.

Eldorado's Northern Night sky is dominated by the Santa Fe Light Dome

Action Update: Santa Fe Lighting


A win that gives us an opportunity 

At the Wednesday, 24 February City Council meeting we won an opportunity to make a real and positive change in the Santa Fe City lighting. We also found a real champion of our cause on the Santa Fe City Council: Councilor Mike Garcia. 

The upshot of the meeting is that question of light color temperature is now open for discussion. The City Public Works Department will hold public hearings before making a recommendation to the Council on a detailed lighting plan. NM DOT is on record as being perfectly comfortable with highway lighting temperatures as low as 2700 K. 

We have moved the needle: now, we need to make it stick. That means work proactively to get the question of street lighting right: to correct the remaining misconceptions about light color temperature, public health and safety, and night sky protection, and show that there are lighting solutions that are safe for City residents where they live and where they drive, and protective of our shared night sky. 

We have work to do: let’s get to it!

Eldorado's Northern Night sky is dominated by the Santa Fe Light Dome

Take Action: Santa Fe City Street Lamp Project


The City of Santa Fe is considering a proposal to replace all of its street lighting. Some of that proposal is good: the new lighting fixtures will be much better shielded than the old. Another part of that proposal is very bad: the new lights will have a much higher “correlated color temperature” (CCT)  than the old lights. The increase in CCT – from 2200 K to (depending on the light) 3000 K or 4000 K, will – even with the increased shielding, significantly increase the scattered light from Santa Fe City and degrade the night sky in the City and all surrounding areas, including the 285 Corridor.

You can read more about the proposal and our reasons for concern on our site here

Eldorado's Northern Night sky is dominated by the Santa Fe Light Dome
Eldorado’s Northern Night Sky, January 2020. The skyline is dominated by the lights of Santa Fe, whose light dome obliterates all but the brightest stars through a 30 degree elevation. Santa Fe City’s proposal to increase the color temperature of its street lights from 2200 K to either 3000 K or 4000 K would greatly increase the intensity of the City’s lights in the 285 Corridor.

Following is a template that you might use to contact the Santa Fe Mayor and members of the City Council, to urge postponement of the final decision (scheduled for Wednesday, 24 February 2021) on the new street lighting until the city has an opportunity to hear from subject experts, sample the experience of peer cities who have travelled down this road, and properly address public concerns. 

Dear Santa Fe Mayor and City Councilors: 

I am a [[XX]]-year resident of Santa Fe, having moved here from the [[WHERE]], attracted by its quality of life, its respect for the environment, and its glorious dark skies. I am writing to you now to express my concern with one aspect of the City’s plan to improve its street lighting, which you will be taking up this Wednesday. 

My particular concern is with the choice of a high correlated color temperature (CCT) – 3000 K to 4000 K – for the street lighting. Such a choice is generally recognized by the medical community, lighting security experts, and the astronomical community for its documented negative effects on human health, highway safety, and night sky protection. 

[Optional Paragraphs:]

Such a choice is contrary to the recommendation of the American Medial Association, which has advised that outdoor night-time lighting should not exceed a CCT of 3000 K, and is best kept below that level. 

Security consultancies advise keeping lighting CCT below 3000 K to preserve the ability of security cameras to accurately render color and avoid being blinded by the increased glare and scattering associated with higher CCT lighting. 

Highway safety experts have long noted that high CCT lighting increases roadway glare, and that low (2200 K – 2700 K) lighting is preferred for its superior penetrating ability through dust and other particulates.

The professional astronomical community has documented the very damaging effects that high CCT lighting has on the night sky: effects that can be measured hundreds of miles from a city’s center.

[End optional paragraphs]

The Thursday, February 18 article in the Santa Fe New Mexican strongly suggests that the City has not properly consulted current expert advice and best practice recommendations regarding the CCT of lighting for road and highway safety, human health, and its effects on the night sky. Certainly the choices that are being recommended for Santa Fe run counter to the choices made by other municipalities of similar size, geography, and demographics. 

Correspondingly, I urge you to postpone any decision on this matter and take additional time to ensure that you have heard from subject experts, sample peer-city experiences, and properly address public concerns. 

Sincerely, 

Name, Address

Send your letter to the Mayor and City Councilors:

Mayor Alan Webber: mayor@santafenm.gov

Councilor Renee Villarreal: rdvillarreal@santafenm.gov

Councilor Michael Garcia: mjgarcia@santafenm..gov

Councilor Chris Rivera: cmrivera@santafenm.gov

Councilor Jamie Cassutt-Sanchez: jcsanchez@santafenm.gov

 

Councilor Signe I. Lindell: silindell@santafenm.gov

Councilor Carol Romero Wirth: romero-wirth@santafenm.gov

Councilor Roman “Tiger”Abeyta: rrabeyta@santafenm.gov

Councilor JoAnne Vigil Coppler: jvcoppler@santafenm.gov

Full Moon over Eldorado

NightSky285 Launch!

Full Moon over Eldorado
Full Moon over Eldorado

The web home of Save The Night Sky 285!

At our web home you’ll find

  • Our goals and the Principles of Responsible Lighting;
  • Our current activities aimed at preserving, protecting, and restoring our night skies;
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