This problem significantly worsens during periods of migration, with most neo-tropical songbirds migrating at night.
Collisions with buildings kill 1 billion birds a year.
Skyglow caused by our artificial lights can attract birds up to 3 miles away!
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As a result, they frequently hit buildings leaving them vulnerable to predators, dead upon impact, or exhausted and overtly stressed.
For wildlife, many essential survival activities are carried on at night, and those activities depend on the
night being dark. Research has now conclusively demonstrated that what scientists call ALAN (artificial
light at night) is a serious problem for wild animals of all types and sizes. That’s no surprise when you
consider that 69 percent of mammals, 30 percent of all vertebrates, and 60 percent of invertebrates are
nocturnal.
Most neo-tropical songbirds migrate at night to avoid turbulence in the air
and to utilize the stars for navigation.
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In the eleven years that they have monitored downtown, Lights Out DC (organized by City Wildlife)
volunteers have found more than 6,000 dead and injured birds!
If the entire city were surveyed this number would considerably grow!
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Across the country, collisions with buildings kill more birds than any other single human factor
besides habitat loss and domestic cats.
Height is not the governing factor here:
In 2014, Smithsonian researchers
estimated that buildings one to three stories tall accounted for 44% of all bird fatalities annually.
Exhaustion is a further lethal consequence for birds confronted by ALAN.
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The 9/11 memorial in NYC, “Tribute in Light,” was found to draw in huge numbers of migrating birds, up to 150 times more than when there are no appreciable lights on.
When lit, birds get “trapped” by the memorial’s light beams, becoming confused and circling endlessly, using up critical energy stores.
A similar problem happens locally here with the Washington Monument. Confusing birds, leading them to fly in circles tirelessly until the lights fade.
For NYC a remedy was sought and now bird monitors communicate with the memorial’s organizers at critical migration periods and the lights are turned off for 30 minutes, helping the birds move on.
Throughout the year our light illuminates the
habitats for many species.
Overt amounts of unnatural light can alter the traditional predator-prey relationship, and cause migratory species to avoid essential habitats.
​Many bat species, including the Little Brown Bat - a Species of Greatest Conservation Need in the District of Columbia - and the Long-eared Bat -an endangered species that resides in D.C. - scrupulously avoid lights, so that areas lit at night become dead
zones for them where they dare not hunt.
Insects are in trouble world-wide, and light pollution is a contributing factor to their decline.
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About a third of the insects who are attracted to an artificial light will die before dawn of predation, collision, or exhaustion.
Fireflies, in particular, are threatened by light pollution.
One in three species of firefly in the U.S. is threatened with extinction,
and a major reason behind their disappearance is that their breeding routines are interrupted by outdoor lights.
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A study in the suburbs of Boston proved that a single bright
porch light can prevent every single firefly in that yard from reproducing.
Many firefly species use bioluminescence to find mates.
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When artificial lights are present, it can disrupt these mating patterns.
The flashing fireflies you see are males (for the most part), whereas females usually stay on the ground and flash much more subtly.
However, in artificial lighting conditions, it can be too bright for the females and males to see each other's flashes.
This can lead to unsuccessful mating displays and affect firefly populations.
Additionally, artificial lights are thought to disrupt circadian rhythms of fireflies, causing confusion about time of day and throwing off the timing of mating displays.
All species depend on the cues and triggers that they receive from both seasonal and circadian prompts.
Plants, too, have been affected by light pollution.
The photoreceptors in plants perceive changes in the intensity, direction and duration of light
which in turn signal a range of vital functions, such as when to bloom or drop leaves
in readiness for colder months.
When exposed to artificial light at night, plants perceive a shorter nighttime,
and in some cases, none at all.
This disrupts their growth patterns and their fragile relationship with pollinators.
Artificial lights at night cause many species to respond to stimuli that is mis-timed.
The synergistic interplay between species is disrupted, whether these be actions
primarily integral to survival or secondary consequences,
as between plant crops and pollinators.
Behaviors such as migration can be prompted too early or too
late, missing ideal climate conditions for any given species’ nesting and
foraging needs
Considering that the world has already lost more than two-thirds of its wild
animals in the last 50 years and that the populations of more than half of the
world’s animals are in serious decline, all of us need to do what we can to ensure
survival of the wildlife that we have left.
Turning out lights at night is a good place to start — it’s easy and it’s effective!
