Light pollution's glare threatens all kinds of wildlife

        Global insect populations have declined by as much as 75 percent during the past 50 years, according to scientists, potentially leading to catastrophic impacts on wildlife, the environment and human health. Most studies point to habitat loss, climate change, industrial farming and pesticide use as the main factors driving the loss of insects, but a new study in the United Kingdom points to another cause: light pollution.
        The ever-increasing glow of artificial light from street lights, especially LED lights, was found to have detrimental effects on the behavior of moths, resulting in a reduction in caterpillar numbers by half. And since birds and other wildlife rely on caterpillars as an important food source, the consequences of this decline could be devastating.
        According to Douglas Boyes of the UK Centre for Ecology & Hydrology, street lights cause nocturnal moths to postpone laying their eggs while also making the insects more visible to predators

such as bats. In addition, caterpillars that hatch near artificial light exhibit abnormal feeding behavior.
        But moths are not the only wildlife affected by artificial light.
        Since most songbirds migrate at night, birds that have evolved to use the moon and stars as navigational tools during migration often become disoriented when flying over a landscape illuminated with artificial light.
        “City centers that are very bright at night can act as attractants to migrating birds,” said ornithologist Charles Clarkson, director of avian research at the Audubon Society of Rhode Island. “They get pulled toward cities, and when they find themselves amid heavily lit buildings, they become disoriented, leading to a large number of window strikes and increased mortality.”
        It is unclear why birds are attracted to lights, but studies have found increasing densities of migrating birds the closer one gets to cities.
        “Birds probably see these cities on the horizon from a long distance, and they get pulled toward these locations en masse,” Clarkson said.
        Street lights have also been found to be problematic to birds. Birds are active later into the evening when they are exposed to nearby artificial lighting at night, and they often sing later as well.
        “Sometimes that might lead to more food availability, since lights attract insects,” Clarkson said. “But it also affects the physiology of the birds when they’re active when they should be sleeping. Some birds that live in heavily lit urban or suburban areas begin nesting earlier, too, up to a month earlier than they typically would. And that leads to a phenological mismatch between when food is traditionally available and when the chicks are hatching and need to be fed.”
        Artificial lighting may cause other species to face a similar mismatch. Christopher Thawley, a lecturer and researcher in the Department of Biological Sciences at the University of Rhode Island, studied lizards in Florida and found not only that the reptiles advanced the onset of breeding when exposed to artificial light, but they also laid more eggs and even grew larger under artificial lighting conditions. Other kinds of wildlife could have comparable results.
        “Light at night can sometimes mimic a longer day length, and a lot of animals use length of day as a cue for when to start breeding,” he said. “If they’re exposed to light at night, they think the days are longer so it must be time to breed. Length of daylight is also a good cue for when to migrate or when to start calling, and that could potentially be an issue for some species.”
        Thawley said frogs that call at night near artificial light could be more vulnerable to predators.
        “When nights are darker, frogs call more, and when the moon is bright they call less,” he said. “It’s more dangerous to call during a full moon because predators could see you. That would be especially true under artificial lighting conditions, too.”
        Scientists are still trying to understand the intricacies of how light pollution impacts wildlife, and yet some cities are already taking action to reduce its impact. Dozens of cities around the United States and Canada, including Boston, New York, Chicago and Washington, D.C., have launched “lights out” programs aimed at dimming city lights during the peak of bird migration.
        Providence is not among the cities participating in a “lights out” program, but local advocates have discussed how to get it started for several years. They say it would be a positive first step toward reducing the impact of artificial lighting on local and migrating wildlife.
        

        This article first appeared on EcoRI.org on September 29, 2021.

Fall means it's time to change

        Every September I’m reminded of that Brady Bunch episode when Bobby’s voice changes just as the Brady kids are about to record an album. They make the best of it by featuring his unreliably squeaky voice in a new song called “It’s time to change.”
        I’m reminded of that because September is the beginning of a time of change in the natural world. We know it best from the changing fall foliage, when many of our maple leaves turn red, our oaks turn to orange, and our beeches and birches turn yellow. For many people, the changing foliage colors make autumn their favorite season – especially in northern New England where the tourist economy depends on it.
        But foliage isn’t the only thing that changes colors in fall. Many birds do, too, as they transition from their bright breeding plumage into their drab winter plumage. And that makes it challenging to be a birdwatcher — or at least a bird identifier — when so many species look uncharacteristically dull.
        For many years I avoided birdwatching in the fall, in part because the songbirds were more quiet and therefore harder to find. But I was also frustrated by the difficulties in identifying many of what one field guide has even referred to as the “confusing fall warblers.” But eventually I figured most of them out and now I enjoy the challenge of fall birding.
        It was only recently, however, that I learned why some birds change colors and others don’t.
        In part, it has to do with their behavior on their wintering grounds. Some birds defend a territory during the winter months, just as they do in spring and summer to protect their mate from unwanted attention. In winter, they may be defending an area with an abundance of food instead. And keeping their bright colors helps to draw attention to themselves while protecting their territory.
        Other species flock together in the winter to make it easier to find productive foraging sites, and they no longer have a reason to defend a particular territory. Those birds are more likely to molt from their bright spring plumage into duller colors.
        Birds that look rather drab during the breeding season, like sparrows, tend to remain drab all year. And most resident birds – those that stay here year-round without migrating – also keep the same plumage all year. Though not all.
        It’s a confusing state of affairs, to be honest, but nature has a reason for everything, even though the scientific community hasn’t entirely figured out all the reasons for why things happen as they do.
        Plenty of mammals also change colors in the fall and winter, though not many around Rhode Island. In northern New England, where snow cover is more common throughout the winter, animals like snowshoe hares and weasels exchange their brownish summer pelage for white fur to help camouflage themselves in the snow. Further north, it’s even more common as Arctic foxes, lemmings and other species do the same.
        Around here, it’s mostly white-tailed deer that are a noticeably different color from season to season. In the fall, deer begin to molt their rusty summer coat into a faded brown or gray color. The transition into their darker winter fur, triggered by hormonal changes that occur each fall, helps them to absorb more of the sun’s heat to stay warm in winter.
        Regardless of how or why they do it, these colorful changes play an important role in their life cycle. Now if only I could do something about my ghostly white legs.

        This article first appeared in The Independent on September 25, 2021.

Whales of the Deep

        The small boat maneuvered within yards of a rare True’s beaked whale in the waters near Northeast Canyons and Seamounts Marine National Monument. The researchers held their breath as they tried to attach a digital tag to the animal’s back with a suction cup. Beaked whales seldom come to the surface for long, so the team’s window of opportunity was fleeting, and they had already made several attempts. If the whale dived again, they might not get another chance. Extending a long pole over the whale, they finally slapped the tag on the animal’s back, and the tag held tight. The team erupted in cheers — no one had ever successfully tagged a True’s beaked whale before.
        “We had all worked so hard to get to that moment, and it was a huge accomplishment,” said Danielle Cholewiak, a research ecologist at the Northeast Fisheries Science Center and the leader of the summer 2018 expedition. “For the first time, we were going to have a little more insight into the deep, underwater behavior of this elusive species.”
        Beaked whales are among the most mysterious marine mammals in the world. Because they are rarely seen and disappear underwater for long stretches of time, little is known about their behavior and

True's beaked whale (New England Aquarium)

life cycle. What are they feeding on? Why do they seem to prefer deep canyons? Do they travel widely or remain in one area for most of the year? Where do they reproduce? What is their social structure? The marine national monument 130 miles off the coast of Cape Cod, Massachusetts, is one of the few known places that is home to several beaked whale species, and scientists conducting research there are hoping to answer some of these questions about the unfamiliar cetaceans.
        Beaked whales have a distinct snout like that of a dolphin, and males can be identified by two tusklike teeth. The whales range in size from about 15 to 40 feet long and can weigh more than 12 tons. More than 20 species traverse the world’s oceans, and they prefer deep, offshore waters — unlike most of the best-known whale species, which spend much of their lives on the continental shelf. Most beaked whales are also shy and difficult to approach. Many species look so similar that even scientists find it challenging to tell them apart, and a couple of species are known only from dead specimens that have washed ashore.
        “Often the best way to identify a dead one on the beach is to cut off the head, freeze it and send it to an expert to make the ID from the clean skull,” said Robert Kenney, a retired marine mammal researcher at the University of Rhode Island.
        Three species of beaked whales — True’s, Cuvier’s and Sowerby’s — have been observed in the Northeast Canyons monument, a 4,900-square-mile protected area established by President Barack Obama in 2016 for its diverse habitats and abundant marine life, which includes billfish, tuna, sharks and more than 50 species of corals. The only marine national monument in the Atlantic Ocean, it features four underwater mountains, or seamounts, and three 1-mile-deep canyons at the edge of the continental shelf. The topography facilitates upwelling, a process that brings nutrient-rich cold water to the surface and sustains numerous species, from cod to North Atlantic right whales.
        The monument is “one of the least human-impacted areas of the East Coast,” said marine ecologist Peter Auster from the Mystic Aquarium and University of Connecticut, who started studying the area in 1984.
        In 2020, President Donald Trump signed a proclamation that lifted restrictions on commercial fishing in the monument. NPCA has been advocating for the restoration of the monument’s protections, and the Biden administration is reviewing the legality of the proclamation.
        Since confirming in 2016 that True’s beaked whales visit the monument area, Cholewiak has spent two to four weeks each summer or fall studying the whales at sea. During every expedition, she and her colleagues scan the surface of the water with supersized binoculars mounted on the ship to locate whales up to 7 miles away. Because the animals remain submerged for extended periods, the researchers also use a variety of acoustic tools to detect them and learn about their underwater movement patterns. Cholewiak’s research vessel tows an array of up to eight hydrophones, and the team laid acoustic recorders on the seafloor, for instance, to listen for the unique echolocation sounds the beaked whales make as they forage for squid and other prey.
        “It’s above our hearing range, so we don’t actually hear it ourselves, but we watch for their signals to come in on a computer screen,” Cholewiak said.
        In addition to Cholewiak and her team, researchers from the New England Aquarium in Boston conduct several aerial surveys in the monument each year to count marine mammals and other wildlife visible at the surface. They fly six transects over the monument’s canyons in a twin-engine plane with two observers aboard, and when they spot marine mammals such as beaked whales, they depart from their route to get a closer look.
        “When we see some, we wonder how many we flew past that were down on a dive when we flew over,” said Orla O’Brien, assistant scientist at the aquarium’s Anderson Cabot Center for Ocean Life. “They’re such a cryptic species that every sighting is important.”
        Based on five years of survey data, Cuvier’s and Sowerby’s beaked whales appear to be more common in the monument than True’s, though the aquarium team has observed all three species swimming in the canyon area in most years.
        Cholewiak’s research group, which is affiliated with the National Oceanic and Atmospheric Administration, is slowly learning details of True’s beaked whales’ behavior. The team was the first to distinguish the echolocation sounds made by True’s (pictured below) from those of the closely related Gervais’ beaked whale, for example. And thanks to the data collected from the tagged whale, they finally have an idea of how long and how deep the whales can dive. The tag remained attached to the whale for 13 hours before falling off and floating to the surface. Once it was retrieved, it indicated that the whale had dived nine times to a depth of about 3,200 feet and that each dive lasted between 25 and 40 minutes.
        Data from just one whale isn’t enough to make generalizations about the species, however, so Cholewiak and her team are continuing their efforts to monitor beaked whales. The pandemic halted progress in 2020, but the researchers were planning to return to the monument this September. One of their longer-term goals is to tag both True’s and Cuvier’s beaked whales to track their movements and interactions to better understand how the two species may be sharing or partitioning their habitat.
        “I feel really excited and energized by this work,” she said. “We still have a lot to learn, but we’re definitely learning something new about beaked whales every time we get out there.”

        This article first appeared in the fall 2021 issue of National Parks magazine.