Research points to rural light’s negative impact on migrating birds
By Mike Lynch
On an early May night, Paul Smith’s College sophomore Nik Main sat in a mostly empty classroom, taking turns with a few others listening to call notes from birds migrating overhead in the dark sky.
The calls were coming down into the classroom through a rooftop microphone that had been set up the previous summer to track the number and types of migrating birds that fly in the region during the spring and fall migrations. Last August, the station recorded hundreds and sometimes thousands of birds flying through the sky at night.
“I’ve been interested in nocturnal play calls before, but this really kind of opened my eyes,” Main said. “I’ve never had the chance to put on headphones and (observe) it in real time.”
Also in early May, ornithologist Andrew Farnsworth stood near the top of Manhattan’s Empire State Building, watching migrating birds. Farnsworth visually observed 50 to 100 birds flying past him each minute, he said, and some of them bounced off of the building after getting disoriented by its lights.
The contrast in light pollution between New York City and places like Paul Smiths in the Adirondack Park is obvious, but researchers worry that bird migration in even rural America may be affected by manmade illumination.
Bright lights are a fixture in the city while the Adirondack Park is known for its dark evenings.
Birds use natural lights from the stars and sky to orient themselves, in addition to relying on landmarks and an internal compass that senses the Earth’s magnetic fields. The artificial light can disrupt those internal systems and cause them to become disoriented.
Ornithologists have been studying the problems of light pollution with a focus on big cities where the impacts seem to be the greatest. Some of those same researchers say light can be problematic in wilderness areas too, and more research is needed to better understand the impacts in less developed areas. Farnsworth said he’s been talking to his colleagues about this topic for studies in rural America in the coming years.
Trapped by the light
The light attraction for birds is especially heightened on nights when there is fog or a low cloud ceiling that reflects the light creating the glow. That type of weather is prevalent during the peak migration periods in the spring and especially the fall, when many young birds have joined the groups of birds headed south.
For instance, Farnsworth recalled looking up at the 911 Tribute of Light memorial in New York City and seeing thousands of birds circling in the glow spotlighting the sky.
“It’s sort of akin to turning a flashlight up into the sky in a snowstorm … and having snowflakes sort of swirling around you,” he said.
When the light is turned off for 20 minutes or so, the songbirds, warblers in particular, seem to be most vulnerable to this phenomenon, he said. It’s as if they are trapped by the glow, like moths gathering and bouncing off a porch light on a dark summer night.
The result is birds becoming exhausted when they’re flying in circles, and they also become more vulnerable to predation as they are drawn out of the darkness and into more developed areas.
Light attraction also causes birds to become disoriented and sometimes fly into structures, including glass windows.
Up to a 1 billion birds die each year in the U.S. and Canada as a result of collisions with structures, and 56% of those incidents occur at buildings one to four stories tall, according to the U.S. Fish and Wildlife Service. Collisions are the second leading anthropogenic cause of death for birds. Cats, which kill an estimated 2.5 billion per year in the two North American countries, are first.
This light attraction phenomenon is not restricted to birds, either. Studies have shown it causes problems for mammals, reptiles, amphibians, fish and invertebrates.
An Adirondack issue?
But what happens in the Adirondack Park, to which many birds travel for the warmer months? The Adirondacks is one of the darkest places in the Northeast, rivaling places like Maine for a lack of light pollution. Are there potential light places that impact them? During peak migration seasons millions of birds are flying into the region. One night in mid-May, estimates showed 1.5 million birds flew over Essex County alone.
Ornithologist Bill Evans, who is based near Ithaca, set up the bird-call monitoring station at Paul Smith’s College, something he’s been doing for decades. He sees night light as problematic.
“Things like artificial light are a big deal, especially in dark areas like the Adirondacks, because birds evolved nocturnal migration in basically darkness,” he said. “You just had the stars, the moon, and, you know, on fairly light nights, they can see the Earth’s horizon.” In past studies outside the park, Evans said he’s witnessed bright lights at places like convenience stores attracting birds and causing them to get disoriented and stuck circling overhead.
“There can be huge numbers of birds,” he said. “That’s one thing I noticed.”
Kyle Horton, an ornithologist at Colorado State University, said birds can get drawn into areas they might not normally visit.
“In a township, it creates a diffuse problem in a way. The birds are stopping, they’re now delayed. They face more predation,” Horton said.
Some birds are attracted to light, and others will avoid bright areas on a dark landscape, which alters migratory routes, said Clarkson University Professor Tom Langen.
“It’s an interesting question, frankly, because, you know, places like Lake Placid, Saranac Lake, in the Tri-Lakes area are a bright spot in an otherwise very dark background,” Langen said.
Farnsworth lives in New York City, and travels to the Adirondacks to observe birds. He noted that it doesn’t take a skyscraper to kill a bird. Many birds die from hitting single-story structures.
“The bottom line of the collision piece, in terms of where there’s light, and where there are structures, that birds will tend to crash into those things,” Farnsworth said.
Potential problem spots
So where does light pollution exist in the North Country?
David Craig, an amateur astronomer who moved to Keene about eight years ago, said he’s seen more evening light in recent years, although it’s hard to measure.
“It’s noticeably worse enough that when I’m out at night, and I look out, and I’ve noticed the sky glow,” Craig said. “I’m annoyed by it.”
He said it can be seen on the horizon above some communities within the park, such as Lake Placid, but also in the distance from cities like Plattsburgh. Maps tracking light pollution show the greatest light pollution emanating from places outside the park, like Glens Falls, Albany and Montreal.
Inside the park, Lake Placid, which has a vibrant downtown, is a major exuder. Other villages, such as Lake George, Ticonderoga, Old Forge, Saranac Lake and Tupper Lake, also show up on the maps. But some communities have taken steps to mitigate the problem. Keene and Lake Placid have downcast lights on their main streets.
Olympic Regional Development Authority venues also appear to emit a lot of light.
“A really bad offender is the ski jumps in Lake Placid,” Craig said.
He said they are particularly bright during the winter when ORDA staff is making snow. Mount Van Hoevenberg has also drawn criticism for its bright lights.
ORDA communications director Darcy Norfolk said its facilities with outdoor lighting mainly operate in winter, outside of the spring and fall migration periods. In addition, day use areas on the forest preserve, such as the ski resorts, Whiteface in Lake Placid and Gore in North Creek, don’t operate overnight at any time of the year.
Norfolk said ORDA abides by the state’s Lights Out Initiative, which requires non-essential lights to be off from 11 p.m. to dawn, among other things, during bird migration periods. She also noted that ORDA facilities not in the forest preserve can dim lights and use blinds.
In addition, the ski jumps use a blinking light near its highest point to alert airplane pilots, not solid lights that are known to attract birds.
State administrators also must adhere to a 2014 New York law that focuses on reducing light pollution at state facilities. They are required to shield light sources from above to reduce sky glow and take other measures that decrease glare.
State Adirondack Park Agency spokesman Keith McKeever said the APA mitigates light pollution on private property through permit conditions. The agency may require outdoor lights to be fully shielded from the sky to reduce sky glow and potential disruption to neighbors and wildlife.
State lawmakers are also considering proposed legislation. The Dark Skies Protection Act would in effect focus on reducing light pollution statewide. The Adirondack Council is one of the act’s biggest supporters. Kevin Chlad, director of government relations for the council, said it’s important to fight light pollution statewide and in the park because dark skies are such an important characteristic here.
“It’s one of those things that if we don’t take action and have a plan to make sure that we’re protecting our night sky, we could look back at a decade or two from now and say, ‘Wow, we lost something that is really special about this park,’” Chlad said.
This article appeared in a recent issue of Adirondack Explorer magazine.
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