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i'd rather learn from one bird how to sing than teach ten thousand stars how not to dance.
- e.e. cummings (1894 - 1962)

Light Pollution Kills Birds in the Environment

This page covers:

Light pollution's impact on other species in the environment are found here.

The sea-bird wheeling round it, with the din
of wings and winds and solitary cries,
Blinded and maddened by the light within,
Dashes himself against the glare, and dies.

Extract from The Lighthouse in The Seaside and the Fireside (1850)
by Henry Wadsworth Longfellow


Many species of birds, especially the small insect-eaters, migrate at night.  Migrating and nocturnal birds will use the light from the Moon and stars and the setting Sun for navigation during their bi-annual migrations.  Light pollution hides their navigational aids.  Artificial, city lights especially interfere with this instinctive behavior.  It draws night-migrating birds toward brightly-lit buildings in urban areas.  The Fatal Light Awareness Program reports that researchers have used radar imagery to determine how birds respond to lit environments.  They observed that once birds fly through a lit environment, they'll return to that lit source and then hesitate to leave it, and in doing so, become trapped in cities that offer little food for them.  The birds then often crash into brilliantly-lit broadcast towers or buildings, or circle them until they drop from exhaustion.  Finally, once on the ground, stunned or injured birds become vulnerable to predation.  The pictures they have collected are stunning and awfully gruesome.

Lights Out Toronto!

The City of Toronto has been for years promoting their own campaign to protect migratory birds called "Lights Out Toronto!"  Here's an example of one of their informational posters:

Lights Out Toronto's banner message that Lights Kill Birds.   Lured by lights at night, migrating birds crash into buildings.

Thank you, Toronto!

Lights Out South Florida!

Right down here in South Florida is the Tropical Audubon Society in Miami. They are seeking to raise awareness that there continues to be lit buildings right here in South Florida.  The state is a main pathway for North American migratory birds, as they use it to either springboard their way from the continent to over winter in the Carribean, or just come and stay local.   Tropical Audubon Society link

Brightly lit buildings in their way, especially those with projection lights or searchlights emitted from them, are a hazard to the birds' safety.  Do any managers of such building, such as some commericial buildings, really believe that all their lights will cause more people to actually go to them?

And how callous must we be, when an estimated 900 million birds die each year from collisons with our buildings?  The actions to solve include simply using shade curtains to contain our lights, or to turn off lights when not using them, to make certain that outdoor lights point down, and not up or outwards, and to use timers on them, too.  More about the deadly effects these buildings and towers have is found down below.

Hundreds of dead birds found outside high school

Source: The Times West Virginian, Fairmont, WV, September 30, 2008

Jake Stump

When teachers and students arrived at Tucker County High School, they found hundreds of dead birds scattered along the parking lot and school property.

The Assistant Principal Mickel Bonnett encountered birds swarming around the school and flying into the windows when he came to work around 6:30 a.m. Monday.  "They were swarming around the lighted entry trying to get into the school," Bonnett recalled. "I thought that was unusual, and then I saw dead birds. I saw more birds flying around and banging into the glass and decided to call the superintendent."  Bonnett said he thought the birds were attracted to the lights inside the school as it was dark outside. One after one, they continued smacking into the side of the school, plummeting to their death.

"Anywhere that had light shining out, they were flying their bodies into the glass," Bonnett said. "It was instant death. They broke their necks and were lying in piles by the door. Some were out by the track, the driveway, spread all over the place. I figure some of them didn't hit so hard, fractured their skulls and died elsewhere."  Officials closed the school Monday morning after fears that toxins might have killed the birds. Several of the creatures were left stunned and recovered.

West Virginia Division of Natural Resources spokesman Hoy Murphy said wildlife officials at the scene found the birds piled up against one wall under a window, on the roof and scattered throughout the school grounds.

The DNR believes that the birds, which were mostly yellow warblers, were migrating from North America to South America for the winter.  They theorized that the birds became disoriented from the fog and lighting around the school and proceeded to fly into structures.  "Migratory songbirds migrate at night and use stars to navigate," Murphy said.  "If stars are obscured by clouds or fog, they will orient to almost any elevated light source to attempt to navigate."  Heavy fog was blanketing the area early Monday, and it's likely that the illumination from the school lured birds in, he said.  The school, located in Hambleton, sits on a hill and remains lit at night.

"This sort of attempt typically leads to a mortality event as the birds circle the light source, become exhausted and either collide with objects or are grounded from the exhaustion -- this is likely what happened here," Murphy said. "The same thing happened a couple of years ago when a very bright light was left on during fall migration on a foggy night at the (nearby) Fairfax Stone wind power facility."

Other types of birds also included thrushes, around 10 warbler species, yellow-billed cuckoo, catbird and sparrows, said DNR ornithologist Rob Tallman, who was at the scene.  Tallman said this type of problem isn't all that unusual in the fall season. He said similar incidents have occurred around cell phone towers, Snowshoe Mountain Resort and other facilities.  "We're trying to remedy the situation by turning the lights off for the short-term and providing them with other lighting options that aren't as attractive to birds."

The neighboring windmills, which are believed to pose a threat to bats and birds, were not considered a cause of the deaths, officials said.  Windmills are located about a mile from the school.  Tallman said officials visited a nearby windmill site Monday and only found a couple of dead birds that had been there for several days.

For precautionary measures, DNR wildlife disease specialist Jim Crum has requested samples to be analyzed for avian flu.  Officials said there were 100 percent certain, however, that this wasn't the cause of a virus.

Hawaii birds confuse Friday night lights with Moon

Source: Associated Press - Fri Oct 22nd, 2010 7:14 pm ET

KAPAA, Hawaii - The annual emergence of the Newell's shearwater fledgling birds have been disrupted by the football stadium lights of local high schools in Kauai County. The young birds mistake the bright lights at sports fields, hotels, parking lots and other places for the Moon and stars, leading them to repeatedly fly around in circles.

They become exhausted and eventually drop to the ground, where they're often attacked by cats or hit by cars unless they are rescued by volunteers. The species is also threatened by pigs and goats that trample on their nests. The fledglings take off between Sept. 15th and Dec. 15th each year, which occurs in the middle of the football season.

The Newell's shearwater birds' population, which numbered about 80,000 in the mid-1990s, has plunged 75 percent in recent years as Kauai grew in size and added more lights that confuse the birds. In 2005, The U.S. Justice Department said federal wildlife officials notified the county that its lighting was hurting the birds, in violation of the Endangered Species Act and the Migratory Bird Treaty Act. The government said the county failed to install shielded lights that shine down on the field, not out, thus being less harmful to the birds.

So, this season, rather than face possible federal prosecution for failing to protect seabirds, the Kauai Interscholastic Federation changed the football schedule so its Friday night games would run on Saturday afternoons instead. For those days closest to a full Moon, schools allow later games because birds are less likely to be confused by artificial lights.

Due to the schedule changes, game attendance is down an estimated 14.5%. Fans don't like sitting in the hot Hawaiian sun and players complain about the high daytime heat. Players are advised to be extra vigilant against heatstroke by drinking more water.

The county ultimately reached a deal with prosecutors in which officials will install shielded lights at Kauai's three football fields by next season. Any night games next year will have to be played under the specially designed shielded lights, and the county must have an escrow account to cover fines for any birds downed during the games. (Note that the shielding should allow the schools to use less electricity as more of each light will be directed downwards on the fields where it is used.)

However, instead of finding ways to solve the problem and not to hurt this fellow species on our planet, some of the around 2% of the local population that attends the games is angered at the birds. T-shirts have been made to declare their preference for night games rather than be concerned this species is threatening to become permanently extinct. And there are reports that island residents warned that some people are talking about refusing to rescue birds they see on the ground just to protest the Saturday games.

How do geese know when to fly to the sun?
Who tells them the seasons?
How do we, humans know when it is time to move on?
As with the migrant birds, so surely with us, there is a voice within if only we would listen to it, that tells us certainly when to go forth into the unknown.

- Elisabeth Kubler-Ross (Swiss-American psychiatrist and author)

Artificial Night Lighting Affects Dawn Song, Extra-Pair Siring Success, and Lay Date in Songbirds

Source: Current Biology, 16 September 2010, Volume 20, Issue 19, pages 1735-1739. 10.1016/j.cub.2010.08.028.

Bart Kempenaers1,*, Pernilla Borgström1,2, Peter Loës1, Emmi Schlicht1, Mihai Valcu1
1Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319 Seewiesen, Germany
2Present address: Department of Animal Ecology, Lund University, Ecology Building, Sölvegatan 37, 22362 Lund, Sweden

Some effects of light pollution can be disruptive as it can directly affect a species, such as moths' fatal attraction to light or the way that lighted towers can also attract, confuse and kill birds. However other effects are more subtle in that they interfere with natural timing patterns that a species depends on. Such cases warrant additional investigations to understand how this affects a species, which is the point of this study.

"In comparison to chemical and noise pollution, light pollution is more subtle, and its effects have perhaps not received the attention they deserve," said Bart Kempenaers of the Max Planck Institute for Ornithology in Germany. "Our findings show clearly that light pollution influences the timing of breeding behavior, with unknown consequences for bird populations." It is these unknown consequences over the long term that needs to be understood.

In this study, the researchers compared the behavior differences of birds deep in forested areas with those living near edges that were next to roads, either with or without streetlights.

The first thing they wrote about is the affect that artificial night lighting had on the dawn song of five common forest-breeding songbirds, namely the Chaffinch (Fringilla coelebs), the Blue Tit (Cyanistes caeruleus), the Great Tit (Parus major), the Blackbird (Turdus merula), the Robin (Erithacus rubecula). Dawn song is that first song males sing at or before dawn and for the females of the species, the song's early timing is often a measure of the quality of the males, meaning older males as opposed to yearlings.

They recorded the songs of the males using a software package called Audacity. The start of the sound file's timings was compared to the timings of sunrise. The researchers found that the songs of each species were easily distinguishable from the background noise; both in the audio but also in the visual sonograms, with the only difficulties were those during rainy mornings.

In four of those five species, males near street lights started singing significantly earlier in the morning than did those males in other parts of the forest. Example, for the 19 days that the study ran, the robins in area without artificial lights started singing 45 - 67 minutes before dawn, while those near streetlights started singing 105 - 145 minutes before dawn. These earlier dawn songs falsify the males advertised "quality" and can help these males of lower quality breed. What this does to the species as a whole over the long term needs to be looked at. While an earlier study had suggested that robins were more affected by daytime noise rather than lighting levels, the authors point out that in their study noise levels were very low and that the males started singing before dawn and long before most noisy humans start becoming active for the day.

They authors also wrote that, over a seven year period, blue tits showed a real change in their reproduction when comparing behavior near streetlights with those without lights. The change was that, on average, females near lights laid their eggs 1.5 days earlier than those in the dark, this may lead to a mismatch between the timings of peak food demand from their baby chicks and the peak timing of food that is available.

For the illuminated males of the blue tits, they had more success in pairings with females. While that may sound good for these males, the authors caution that they may get less sleep and be at higher risks of predation. The authors state that it would be hard to quantify such factors.

An Estimate of Avian Mortality at Communication Towers in the United States and Canada

Source: PLoS ONE, April 2012, Volume 7, Issue 4, e34025, pages 1-17. Article info:doi/10.1371/journal.pone.0034025.

Longcore, T., C. Rich, P. Mineau, B. MacDonald, D. Bert, L. M. Sullivan, E. Mutrie, S. A. Gauthreaux Jr., M. L. Avery, R. L. Crawford, A. M. Manville II, E. R. Travis, and D. Drake 2012.

UWG's Travis Longcore and Catherine Rich, published a scientific paper estimating avian mortality at communication towers in April 2012 in PLoS ONE. They describe how birds are attracted to the lights during nocturnal migration and collide with the towers and the cables holding them up. UWG's GIS consultant, Beau MacDonald, integrated (and did quality control on) three sources of tower data and made the maps. Agency representatives from the United States and Canada, as well as several pioneers in tower mortality studies collaborated on the paper.   Lighted Communications Tower
Birds are attracted to the color red.  In this image, can you see the guy wires stabilzing the tower?  Could birds see the wires as they quickly fly into them?


Avian mortality at communication towers in the continental United States and Canada is an issue of pressing conservation concern.  Previous estimates of this mortality have been based on limited data and have not included Canada.  We compiled a database of communication towers in the continental United States and Canada and estimated avian mortality by tower with a regression relating avian mortality to tower height.  This equation was derived from 38 tower studies for which mortality data were available and corrected for sampling effort, search efficiency, and scavenging where appropriate.  Although most studies document mortality at guyed towers with steady-burning lights, we accounted for lower mortality at towers without guy wires or steady-burning lights by adjusting estimates based on published studies.  The resulting estimate of mortality at towers is 6.8 million birds per year in the United States and Canada.  Bootstrapped subsampling indicated that the regression was robust to the choice of studies included and a comparison of multiple regression models showed that incorporating sampling, scavenging, and search efficiency adjustments improved model fit. Estimating total avian mortality is only a first step in developing an assessment of the biological significance of mortality at communication towers for individual species or groups of species.  Nevertheless, our estimate can be used to evaluate this source of mortality, develop subsequent per-species mortality estimates, and motivate policy action.

Communication towers, lights, and birds: successful methods of reducing the frequency of avian collisions

Source: Ecological Applications, 19(2), 2009, pp. 505–514
by the Ecological Society of America

1 Central Michigan University, Department of Biology, Mount Pleasant, Michigan 48859 USA
2 Curry & Kerlinger, LLC, P.O. Box 453, Cape May Point, New Jersey 08212 USA
3 Division of Migratory Bird Management, U.S. Fish and Wildlife Service, 4401 North Fairfax Drive, MBSP-4107,
    Arlington, Virginia 22203 USA
4 Present address: Michigan Natural Features Inventory, Stevens T. Mason Building, P.O. Box 30444,
    Lansing, Michigan 48909-7944 USA. E-mail:


Estimates suggest that each year millions of birds, predominantly Neotropical migrating songbirds, collide with communication towers.  To determine the relative collision risks that different nighttime Federal Aviation Administration (FAA) communication tower obstruction lighting systems pose to night-migrating birds, we compared fatalities at towers with different systems: white strobe lights only; red strobe-like lights only; red, flashing, incandescent lights only; and red, strobe-like lights combined with non-flashing, steady-burning, red lights.  Avian fatality data used to compare these tower light systems were collected simultaneously in Michigan on 20 consecutive days during early morning hours during peak songbird migration at 24 towers in May and September 2005 (total = 40 days) .Twenty-one towers were 116–146 m above ground level (AGL), and three were >= 305 m AGL . During the two 20-day sample periods, we found a mean of 3.7 birds under 116–146 m AGL towers equipped with only red or white flashing obstruction lights, whereas towers with non-flashing/steady-burning lights in addition to the flashing lights were responsible for 13.0 fatalities per season. Kruskal-Wallis test, ANOVA, Student’s 't' test, and multiple comparisons procedures determined that towers lit at night with only flashing lights were involved in significantly fewer avian fatalities than towers lit with systems that included the FAA ‘‘status quo’’ lighting system (i.e., a combination of red, flashing lights and red, non-flashing lights).  There were no significant differences in fatality rates among towers lit with red strobes, white strobes, and red, incandescent, flashing lights.  Results from related studies at the same towers in May and September 2004 and September 2003 provide ancillary support for these findings .Our results suggest that avian fatalities can be reduced, perhaps by 50–71 %, at guyed communication towers by removing non-flashing/steady-burning red lights.  Our lighting change proposal can be accomplished at minimal cost on existing towers, and such changes on new or existing towers greatly reduce the cost of tower operation.  Removing non-flashing lights from towers is one of the most effective and economically feasible means of achieving a significant reduction in avian fatalities at existing communication towers.

Department of Physics
Florida Atlantic University
Boca Raton, Florida
E-mail: evandern at fau dot edu
Phone: 561 297 STAR (7827)