From the Winter 2024 issue of Living Bird magazine. Subscribe now.

In July 2023, the Cornell Lab of Ornithology community lost a dear friend and colleague when Tom Johnson passed away unexpectedly at the age of 35.

Tom’s extraordinary skills in photography, bird identification, and as a birding tour guide were driven by how much he loved being out in nature. Johnson generously contributed more than 10,000 photos, audio, and video recordings to the Cornell Lab over two decades, from his high school years through his 2010 graduation from Cornell University and beyond.

“Beyond his formidable skills and inspiring passion for birding, Tom was an even more outstanding person,” wrote Ian Owens, the executive director of the Cornell Lab. “His warmth, thoughtfulness, humility, and generosity of spirit made him an exemplary ambassador for birds and the natural world and a dear friend to many.”

An Eye for Beauty

“Tom had an easy, warm way about him, immediately making anyone he was with feel comfortable,” says Brian Sullivan, a Cornell Lab digital publications project leader and close friend of Johnson’s. “He had the kind of charisma that made others feel seen and heard. He would want us to keep seeing all the beauty around us—the heartbeat of the planet that he loved so much, the beauty that never escaped his eyes.” 

All photos are by Tom Johnson. Tap/click links to view larger photos via their Macaulay Library archive page.

Warblers in Flight

From an early age, Tom seemed to possess a natural gift for taking bird photos. By the time he was an undergraduate at Cornell, in the late 2000s, he was already capturing split-second flight shots of tiny birds on the move against a limitless sky. None were more impressive than his warbler photos, many of them taken at dawn from the observation platform at Higbee Beach in his beloved Cape May, New Jersey. For most of us, getting a well-lit, well-focused flight shot of any kind is cause for celebration; over the years Tom captured brilliant flight shots of well over 20 warbler species, including seldom-seen treasures like Cerulean, Connecticut, and Golden-winged Warblers.

Perhaps the single best illustration of Tom’s personality, talent, and dedication is a photo of a Prothonotary Warbler he found in the middle of the night on a ship south of Nantucket, Massachusetts. As noted on an eBird checklist from the day, Tom heard the bird’s chip note in his sleep and woke up at 2:30 a.m. Taking his camera along to investigate, he ended up capturing this dramatic flight shot, in near-complete darkness, miles from land.

A Connection With Seabirds

For several years after Tom’s graduation he served as a seabird observer on NOAA research ships—an opportunity to sharpen his formidable observational skills with some of the bird world’s most notorious identification challenges. Tom was nicknamed “Albatross” by his Field Guides colleagues, and his affinity for these wide-ranging, restless, and ineffably graceful creatures is clear from the images he brought home. A bird like a Southern Royal Albatross may seem large, but against the endless sweep of a gray ocean even this massive seabird is a challenge to capture in a camera frame.

Frontiers of Identification

Birding is about noticing details—it’s what brings a sense of discovery and possibility to every trip outside. Tom’s eye for detail was unparalleled, and his ability to key in on nearly invisible differences or irregularities meant he often noticed rare birds that others might have passed by. Imagine watching a swooping swallow and realizing it was not a Cliff Swallow, nor the similar Cave Swallow, but a hybrid of the two? Or standing on a beach in Nome, Alaska, and picking through a hundred White-winged Scoters to find five nearly identical Stejneger’s Scoters. Tom’s eBird checklist illustrates that finely tuned eye, noting the Stejneger’s different head shape, eye blaze, and flank color. (While also noting, with characteristic enthusiasm, that the sighting was “highly awesome.”)

A World of Ability

Tom spent nearly 10 years guiding birding tours for Field Guides, traveling to at least 15 countries on some 120 trips (read a remembrance from Field Guides). In his 35 years, he amassed a tremendous store of knowledge and experience that he shared with anyone in his warm and encouraging way.

“The fields of ornithology and birding combined have suffered a massive loss,” says Sullivan, “as Tom was one of the rare people who had the mix of skills needed to break down the boundaries between these two worlds—he deftly communicated the magic of birds and the power of science to anyone in his path.” Tom had a breadth of knowledge and enthusiasm that spanned from the tropics to the poles.

One of the great privileges of working at the Cornell Lab is the opportunity to spend time with so many talented young birders and ornithologists who come here to study. Tom was one of the very brightest, and we all assumed that we’d be learning from him for decades to come. We are grateful for the time we had with Tom, and we join with his family, friends, and the wider birding community in remembering his life.

Around 96 million people in the U.S. closely observed, fed, or photographed birds; visited public parks to view birds; or maintained plantings and natural areas around the home for the benefit of birds in 2022. That’s more than 35% of the nation’s population aged 16 and over.

The eye-popping figures come from the latest Survey of Fishing, Hunting, and Wildlife-Associated Recreation conducted by the U.S. Fish and Wildlife Service. The estimated total number of birdwatchers is more than double the figure cited in the previous USFWS survey, conducted in 2016.

The report authors caution that survey numbers from 2016 and 2022 are not directly comparable, due to a change in methodology for the data collection. But the new survey results were released amid trending social media chatter and newspaper headlines that reflect a worldwide birding boom in the years since the Covid-19 outbreak in 2020. Cornell Lab of Ornithology participatory-science programs, like the Merlin Bird ID app and eBird, also reflect the heightened interest in avian affairs. For example, as of March 2023 there were more than 1.5 million active Merlin users in the U.S., a fivefold increase from the 300,000 Merlin users in March 2020. Likewise, eBird monthly checklist submissions have doubled, from 600,000 checklists in March 2020 to 1.3 million by May 2023.

The USFWS survey also shows that birding is big business. More than six out of every 10 dollars spent in 2022 on wildlife-related recreation (which also includes hunting and fishing) came from wildlife watching, with birds cited as the greatest focus for wildlife watchers. Altogether, wildlife watchers spent more than $250 billion last year to engage in their hobby—including more than $24 billion on equipment such as binoculars, cameras, and bird food—for an average of $2,188 per person.

Sometimes that spending can add up just by virtue of a single rare bird. A 2023 study published in the journal People and Nature documented that when a Steller’s Sea-Eagle showed up on the New England coast in the winter of 2021–22, eager birders pumped more than $750,000 into the economies of Maine and Massachusetts.

Amanda Rodewald, senior director of the Center for Avian Population Studies at the Cornell Lab, says the report is an important source of information to share with elected officials and shows just how many of their constituents care about the environment and conservation.

“It also underscores how wildlife, especially birds… are economic engines that sustain local, regional, and national economies,” says Rodewald. “Because so many birds are migratory… revenue [from wildlife-related recreation] in a given state may be linked to healthy environments elsewhere. For instance, ducks from the Prairie Pothole region fly to Arkansas, where hunters might pay to harvest them, or birders might travel and spend money to watch them.”

From the Winter 2024 issue of Living Bird magazine. Subscribe now. This story was adapted from a post on TWS Wildlife News, published by The Wildlife Society.

A study model that’s being called an avian version of the dating app Tinder is showing that giving females a bit of choice between prospective mates can drastically improve the output of a captive breeding program for a critically endangered species of Hawaiian honeycreeper.

“If we pair the female with the male that she spends more time with, we get more eggs at the end of the season,” said Alison Greggor, a researcher at the San Diego Zoo Wildlife Alliance.

Akikiki live only in the mountains on the island of Kauai, and only a few dozen remain in the wild, with extinction predicted within the next few years as wildlife managers struggle to find a way to stop the spread of malaria-carrying mosquitoes. In a last-ditch effort to save the species, wildlife managers from a multi-group partnership brought some Akikiki eggs into captivity in 2015. Given the low number of Akikiki left, scientists are looking for ways to improve the fertility of birds in captivity, with hopes of one day releasing them back into the wild.

Most research on captive breeding programs focuses on maximizing the genetic match between mates. But in a study published in the journal Conservation Science and Practice last March, Greggor and her colleagues examined whether allowing a female Akikiki to choose her mate would improve fertility.

The setup is like Tinder for birds: Instead of swiping left or right, the researchers put the female in an aviary in the middle, sandwiched by two enclosures with one male each on either side of her—she could choose the male on the right or the left.

At first, the researchers weren’t sure if they’d be able to tell the females’ preferences. They placed perches near the males on either side and watched, observing interactions like whether females would share food with one male over the other. They found that the female’s choice was best predicted by the male she spent more time next to. And by the end of the breeding season, the researchers found that females paired with their preferred mate would lay four to seven eggs on average, while the females with a nonpreferred male only laid two to three eggs.

“Quite a big difference,” Greggor said, and one that could bring a big boost for the captive breeding program. She points out that this kind of research demonstrates that successful breeding isn’t only about making a good genetic match, and that mate choice can play a large role “for improving breeding outcomes.”

From the Winter 2024 issue of Living Bird magazine. Subscribe now.

Recent research has uncovered an endangered Willow Flycatcher population’s ability to undergo genetic change in order to adapt to climate change.

In a study published in the journal Nature Climate Change last June, researchers documented a genome-wide shift within a population of Willow Flycatchers in San Diego, which scientists think has equipped the unassuming brownish-olive songbirds to better confront escalating wet and humid conditions in coastal southern California.

The Southwestern Willow Flycatcher has been federally protected under the Endangered Species Act since 1995. One of four subspecies of Willow Flycatcher, it has a range across seven states from Texas to California. Many Southwestern Willow Flycatchers in San Diego live in the wet willow thickets along the San Luis Rey River, an area that has experienced increased variability of precipitation patterns and a rise in temperature over the last few decades.

For the study, scientists studied 616 flycatcher specimens dating back to the early 1900s, including 23 specimens from the Cornell University Museum of Vertebrates. They found that the genetic structure of most Southwestern Willow Flycatchers has remained more or less unchanged outside of San Diego. However, when the team performed a whole-genome analysis of Southwestern Willow Flycatchers from San Diego, and compared it to San Diego flycatcher specimens from more than 100 years ago, they found that the present-day flycatchers have a higher prevalence of gene variants associated with adapting to wet and humid conditions.

According to Sheela Turbek, a postdoctoral fellow at Colorado State University and lead author on the study, this genetic change likely stems from interbreeding with other Willow Flycatcher populations. At some point over the past century, Willow Flycatchers from across the Southwest and from the Pacific Northwest (a separate subspecies) have exchanged genetic material with Willow Flycatchers in San Diego. This mixing with neighboring populations introduced new genetic material into Southwestern Willow Flycatchers breeding in San Diego and may have facilitated an evolutionary response to climate change that shows up in the genome of modern-day San Diego birds.

Leonardo Campagna, an ornithologist who was not involved with this research, says that the findings from this paper demonstrate why it’s important to preserve large and interconnected populations of any organism.

“The best way to do that is to protect habitat and the movement of individuals across the landscape,” says Campagna, who is assistant director of the Fuller Evolutionary Biology Program at the Cornell Lab of Ornithology. “Large healthy populations will harbor more genetic variation, and therefore be well equipped to respond to natural selection and adapt in the direction they may need to go.”

From the Winter 2024 issue of Living Bird magazine. Subscribe now.

Kristen Heath-Acre lives in Columbia, Missouri, which officially has a sister-city relationship with Hakusan City, Japan.

But Heath-Acre, the state ornithologist for the Missouri Department of Conservation, says she feels more of a sister-city connection to the town of Santa Marta and the mountain forests near the coast of northern Colombia. Because by looking at a new set of maps produced using eBird data—called eBird Shared Stewardship Maps—Heath-Acre can see that Missouri has a special connection with the Sierra Nevada de Santa Marta, as the winter home of Cerulean Warblers and other migratory songbirds that breed in the Show-Me State.

According to Heath-Acre, recognizing those special migratory-bird connections between places in the north and south is a key to effective conservation for these species that fly up and down the hemisphere.

“Birds on the whole are disappearing. Their populations are declining,” she says. “And so if we are trying to support birds on the whole here in the U.S., we have to look at their whole life cycle, what’s happening throughout the year.”

The Cornell Lab of Ornithology produced these data-driven maps in collaboration with Partners in Flight, a consortium of bird-conservation scientists in the Western Hemisphere. Increasingly, scientists are emphasizing the importance of full life-cycle conservation—preserving and protecting the habitat that a migratory bird needs for both its breeding and nonbreeding periods.

Visualizing Where “Our” Birds Go When They Leave

“We often think of birds as belonging to our states, or belonging to where they are when they’re breeding,” says Sarah Kendrick, a migratory bird biologist with the U.S. Fish and Wildlife Service. “But really, we’re only hosting these birds for a few months of the year. They’re pretty much tropical birds.”

For example, eBird data show that a Cerulean Warbler in Missouri’s Ozarks has a breeding window of about 49 days before preparing for migration. But almost half of that bird’s year—an estimated 149 days—is spent in Colombia during the nonbreeding period.

“We share those migratory bird populations with our conservation partners across the hemisphere,” says Kendrick. “And we know that they’re facing major threats throughout that full year. These eBird stewardship maps help to paint that picture in a really cool visual way, of where our shared birds are traveling beyond our borders.”

The maps are powered by a dataset that consists of 44 million eBird checklists submitted by birders from 14 million locations throughout the Western Hemisphere from 2007 to 2021.

“It’s a lot of data, and basically we can see each species observation in each checklist as a data point,” says Archie Jiang, the Cornell Lab computer programmer who generated the Shared Stewardship Maps. Jiang graduated from Cornell University in May 2023 as a computer science major, and he was an officer in the Cornell Birding Club as an undergrad. “We have this space and time data of where people are observing birds, and this is the raw data that we’re working with.”

Jiang fed modeled eBird data into a sophisticated program (developed by Cornell Lab data scientist Matt Strimas- Mackey) that identified places where migratory birds are concentrated in the nonbreeding season. He then weighted those results by the proportion of bird breeding populations that occur within a targeted state or region, essentially highlighting parts of the map where those birds go on migration. For example, he found that Black-throated Blue Warblers that breed in New York State show a very strong migratory connection to overwintering grounds in Jamaica.

Shared Stewardship Maps

West coast: Linkages for 48 Breeding Species

Rufous Hummingbirds connect the West Coast with Mexico City. In an Indigenous community just south of Mexico City, the Brigada de Monitoreo Biológico Milpa Alta of San Pablo Oztotepec is working to restore subalpine grasslands. This area acts as a year-round refuge for the endemic, endangered Sierra Madre Sparrow, as well as an important overwintering area for Rufous Hummingbirds for 100 days of their nonbreeding season. Urban sprawl threatens the area, but local Indigenous leaders are driving efforts to study, conserve, and sustain the biocultural heritage of their people and their land. 

Midwest: Linkages for 84 Breeding Species

Spotted Sandpipers Connect the Midwest with the Peruvian Coast. All along the Pacific Coast of South America, the nonprofit science group Center for Ornithology and Biodiversity (aka CORBIDI by its Spanish acronym) is working to monitor and protect areas for shorebirds. CORBIDI scientists organize shorebird surveys along the Peruvian coast every four years and load their data into eBird. Their survey data was recently used to nominate and gain government protections for an area of mangroves in northern Peru that had been identified as an important area for Spotted Sandpipers and other shorebirds. 

Northeast: Linkages for 74 Breeding Species

Rose-breasted Grosbeaks Connect the Northeast With the Ecuadorean Andes. Within the Choco Andino Biosphere region, the Mashpi Chocolate farm is regenerating forest that provides food and acts as nonbreeding-season habitat for migratory songbirds such as Rose-breasted Grosbeaks. More than 80% of the farm’s 140 acres have been restored to forest, with more than 200 bird species counted in the latest survey. The farm’s sustainable cacao production carries a Garantía Agroecológica certification—meaning no chemical pesticides or fertilizers are used in producing Mashpi’s fine artisanal chocolate and cocoa delicacies.

Methods Summary: eBird Shared Stewardship Maps with uniqueness nonbreeding connections are generated by calculating the sum of nonbreeding bird abundance in each 3×3 km grid cell for all migratory bird species that breed within a focal region, then weighting by the percent of each species’ breeding population in the focal region. The results are then divided by the total sum of stewardship connections for all regions in the U.S. to emphasize the uniqueness of shared stewardship connections for a particular focal region.

“Birds are one of the things that can link us across large spatial scales,” says Cornell Lab quantitative applied ecologist Andrew Stillman. “These connections have existed for thousands and thousands of years, but they’re really hard to understand. They’re invisible.”

Stillman says that in recent decades, the advent of radio- and GPS-tag tracking technologies allowed scientists to get a glimpse of these migratory connections between places; put a tag on a bird, track it as it flies south, and see where it spends the winter.

But while tracking tags are good for studying individual birds, they can’t yield data that’s useful at the scale of entire populations.

“The ideal information [for conservation scientists] would be if we put a tag on every single, stinking bird in the entire U.S., but we can’t do that,” Stillman says. “These eBird Shared Stewardship Maps provide us with baseline information at the species level.”

Deb Hahn, the international relations director at the Association of Fish and Wildlife Agencies, is putting those eBird maps to good use. Hahn directs the Southern Wings initiative, a partnership of state agencies that connects states with conservation groups in Latin America. Hahn says the eBird Shared Stewardship Maps are extremely valuable in her efforts to show the biological connection between areas in the U.S. and areas south of the border, as she facilitates full life-cycle conservation projects for migratory birds.

“The stewardship maps can help a state agency get a sense of … what areas might be a great place for them to invest in to have more impact on the greatest number of species,” Hahn says.

Through Southern Wings, 41 state agencies have donated nearly $3.9 million to projects in 11 countries in Mexico, Central and South America, and the Caribbean. Hahn thinks the eBird maps will stimulate more such cross-border conservation.

“Having the maps helps us make a stronger case for the need to put conservation dollars in specific areas,” she says.

Importantly, say Cornell Lab scientists, these maps should set the stage for true collaboration between conservation biologists in the U.S. and Latin America.

Setting the Stage for Collaboration

“Ideally, we’re looking at these maps together. That’s really the whole idea behind shared stewardship,” says Viviana Ruiz Gutierrez, a native of Costa Rica who’s the director of conservation science at the Cornell Lab. “It’s not to try to impose a point of view or priority, but it’s more to know where to look for partners and contribute to conservation efforts that are already on the ground in Latin America.”

For example, when the Missouri Department of Conservation wanted to enhance the effectiveness of their conservation funding to turn around declining populations of long-distance migratory birds such as Wood Thrush (a state-designated Species of Greatest Conservation Need), they looked to Latin America—via Southern Wings—to partner up with the Colombian conservation group SELVA.

“SELVA’s recent research on migratory birds has seen huge benefit from cross-border collaboration with U.S. and Canadian government agencies,” says Camila Gómez, a director at SELVA. “These funds go a really long way in Latin America. They have served to employ and build capacity of local researchers, implement research and conservation activities on the ground, and highlight the importance of broad international collaborations to guarantee migratory bird welfare throughout their annual cycle.”

Heath-Acre says she’s proud that Missouri was a leader in the paradigm shift toward full life-cycle conservation.

“These birds don’t realize these borders exist,” she says. “I think Missouri has done a really good job of following the birds where they go, providing funding and support for research where these birds are going.”

According to Sarah Kendrick of the USFWS, the eBird Shared Stewardship Maps could be a catalyst for ramping up full life-cycle conservation efforts. And that’s desperately needed, as U.S. federal and state agencies work to turn around a massive 26% loss among all Neotropical migratory bird populations since 1970, according to research published in Science in 2019.

Says Kendrick, “If we’re not addressing the threats that these birds face when they’re beyond our borders, we’re not doing all we can.”

From the Winter 2024 issue of Living Bird magazine. Subscribe now.

When hordes of chickadees, finches, and woodpeckers descend on a backyard bird feeder, squabbles are bound to erupt: Sometimes getting a choice morsel means muscling your way into position.

Minimizing conflict in these situations is good for birds, says Cornell Lab of Ornithology Research Associate Eliot Miller: “It takes energy to fight, and it can be dangerous, so it usually makes sense to avoid it.”

In 2017, a team led by Miller used Project FeederWatch data to analyze such conflicts—moments when one bird displaces another at a food source. The results, published in the journal Behavioral Ecology, gave rise to a dominance-hierarchy ranking for backyard birds: a guide to which species were most likely to hold their ground in one-on-one confrontations with other species, and which ones were more likely to turn tail and fly.

Now, other scientists are picking up where Miller left off, using an ever-growing set of FeederWatch data to dive deeper into the behaviors, social relationships, and physical traits that shape conflict at the bird feeder.

Biologist Roslyn Dakin of Carleton University in Canada was inspired by Miller’s 2017 study to look into whether a bird’s social tendencies affect their place in the pecking order. For example, some birds, such as finches and House Sparrows, are social butterflies that often visit feeders in groups, while others, such as woodpeckers and nuthatches, are more likely to be lone wolves.

Working with Carleton PhD student Ilias Berberi, Dakin analyzed 6.1 million FeederWatch observations to determine the average group size at feeders for 68 species.

“What we realized once we got into [the FeederWatch data] is that it actually presents all kinds of opportunities that we don’t have otherwise,” says Dakin. “It lets us ask questions that we couldn’t possibly ask through the observations of any one scientist or even a small team of scientists because no one person could observe communities across an entire continent.”

Next the team looked into 55,000 recorded one-on-one dominance interactions in the FeederWatch dataset to see if the loner birds or social birds are better at displacing other birds. Their results, published in the journal Proceedings of the Royal Society B in February 2023, showed that birds like White-breasted Nuthatch and Red-bellied Woodpecker (lone wolves that were among the least social birds in the study) were also among the most likely to displace others. At the other end of the spectrum, the social butterflies that usually visited feeders in groups, such as American Goldfinches and House Sparrows, were most likely to flee the scene when facing off against a foe of similar stature.

But there was a caveat: When these socially inclined birds came to feed in groups, their performance improved. For example, highly social Pine Siskins lose most encounters when they are alone, but when a group of five visits together their individual interactions, on average, become twice as successful.

Conversely, some birds that tend to be lone wolves, like Northern Cardinals, became less successful in feeder showdowns when they visited in groups.

“We think that these effects might be driven by what the birds are paying attention to,” says Dakin. “So maybe when cardinals are there in a group, they’re paying attention to each other and might be more prone to being displaced by a different species.”

Another study, published in 2024 in the journal Nature Communications and led by Gavin Leighton, an assistant professor of biology at Buffalo State University, investigated what happens to the dominance hierarchy when a new face shows up at the bird feeder. Leighton and his team looked at around 1,600 interactions from more than 100 different bird species in the FeederWatch data and determined that “syntopic” species—pairs of species that usually overlap in space and time—get into fights less than expected. On the other hand, species that are not often found together fight more than expected when their paths cross.

For example, chickadees, goldfinches, and juncos seem to avoid getting into scuffles even though they’re often shoulder to shoulder at feeders. On the other hand, chickadees seem to be spoiling for a fight with Yellow-rumped Warblers.

“It all comes down to energy,” says Leighton. “You don’t want to get into fights you know you’ll lose. When birds see each other on a regular basis, they’re more likely to know whether they are the subordinate one or the dominant one. If you are in close proximity to someone you know is likely to beat you, it’s more advantageous to just leave before anything happens.”

Both Dakin and Leighton are continuing to use FeederWatch data to tease apart the social networks at bird feeders. Leighton is currently studying whether harsh weather makes it more likely that a subordinate species will resist in an attack; Dakin is interested in how weather affects group size at bird feeders.

Emma Greig, the project leader for FeederWatch at the Cornell Lab, says she’s thrilled the data is being used in new ways, and that thousands of FeederWatchers are continuing to report dominance interactions in their observations.

“We can use bird counts to infer things about behavior, but now we can also use people’s direct observations of behavioral interactions to learn how birds relate to one another,” says Greig. “It’s really fantastic data.”

For our 2024 photo essay we’re celebrating wonderful photos in five themes: the high-speed action of Thrill of the Chase, a look at our avian neighbors with Birds in Built Environments, a sampler platter of food types with Feeding Time, spectacular poses in Birds Never Cease to Amaze, and a peek at some of the world’s rarest birds with Rare Glimpses. In the final section, we say thank you to all the photographers who make the Macaulay Library archive such a uniquely rich resource.

Thrill of the Chase

As a visual catalog of the life histories of more than 10,000 avian species, the Macaulay Library contains dramatic images that provide a rare look into how birds interact with perceived foes—such as an egret jockeying with an elephant seal for space on the beach—and reliable prey, such as a spring cloud of insects pierced by a sallying Yellow-rumped Warbler. 

Birds in Built Environments

Macaulay Library images provide spectacular evidence that cities can be full of birdlife—with photos of iconic species nesting, roosting, and migrating from Rome to Kathmandu to the grounds of the Taj Mahal in Agra, India. Photographer Jonathan Taffet captured an image of Purple Martins swarming above the Texas A&M University campus. “It was an amazing sight to behold,” he says, “even more amazing that this was not in some national wildlife refuge or state park, but on a campus traversed by 70,000 students.” 

Feeding Time

Many Macaulay Library photos feature anxious nestlings awaiting food or an adult chowing down, providing scientists with imagery to study bird diets. Photographer Steven Meisel documented the delivery of damselflies to Tree Swallow nestlings at a pollinator garden near St. Paul, Minnesota. “The parents were very busy feeding the two hatchlings,” he says, “about every five minutes.“ 

Birds Never Cease to Amaze

Birds sometimes do the weirdest things. When photographers are there to catch these rare moments—like the improbable interaction of a Dunlin standing atop a Willet—they unlock new information about bird species. Sharing these unique photos with the Macaulay Library helps to build a robust archive of little-known bird behaviors. 

Rare Glimpses

Some of the most prized photos in the Macaulay Library are images of the world’s most reclusive and cryptic birds. Photo documentation puts a face to the names of these rare and vulnerable species, which helps fuel the cause for their protection and conservation. 

Thank You, Photographers

Photo by photo, bird song by bird song, the Macaulay Library has grown thanks to the gracious contributions of birders around the world sharing their images, sound recordings, and videos. As a result, the Macaulay Library is a global ornithology resource for the world, helping to further research and conservation.

Every year, scientific journals publish hundreds of research papers based on analyses of audio recordings, photos, and videos from the Macaulay Library. For example, scientists in Peru used the Macaulay Library to better understand the impacts of plastic on seabirds by assessing photos of birds entangled or trapped in plastic. Their results were published last year in the journal Environmental Conservation. Contributions from the worldwide community of birders are making a difference and improving our understanding of birds and their environments. None of this would be possible without the generosity and dedication of contributors to the archive.

Below are just some of the more than 40 photographers featured in this article. From everyone at the Macaulay Library and Cornell Lab of Ornithology, thank you for your time and efforts; we can’t wait to see all that we’ll achieve together in 2024.

From the Winter 2024 issue of Living Bird magazine. Subscribe now.

It’s four in the afternoon and I’m navigating busy streets and skyscrapers on my way to the New York Times Climate Forward Summit in Midtown Manhattan. After a few hours, my senses were overloaded—I was ready for a break. So I made my way over to Bryant Park, a little pocket of green in the shadow of Times Square, to relax.

But to me—fresh off the bus from Ithaca in Upstate New York—the park was anything but serene. Hundreds of people were scattered about, enjoying games and conversation, and practicing yoga. I sat down on a park bench and immediately spotted two White-throated Sparrows and a Common Yellowthroat foraging on the ground, a bit surprising for me to see in such a populated park. I was even more surprised to spot an Ovenbird, a typically reclusive species of hardwood forests.

I ran over to share my news with a couple other birders peering into nearby bushes with their cameras, and it turns out I had only seen the tip of a migratory bird wave that was moving through NYC that day. Earlier someone had spotted a Gray-cheeked Thrush, a Black-and-white Warbler, and a Mourning Warbler in the park.

The diversity of birdlife in cities goes way beyond pigeons. One study published in 2014 in the scientific journal Proceedings of the Royal Society B documented that 20% of the world’s bird species occur in urban areas. In the United States, about 83% of people are crammed into the urban areas that make up only 3% of the nation’s total land area—meaning the birds in America’s big cities are dealing with the same human-generated noise and sensory-overload stresses that I was experiencing in NYC.

A growing body of research is revealing the surprising ways that some bird species are changing to adapt to urban life. Scientists are finding that some birds alter how they sense the world, how they communicate, even their physical characteristics to survive in cities.

But even highly adaptable bird species have their limits. With North American bird populations plummeting by 3 billion birds since 1970, many scientists say it’s time for cities to make some adaptations for the good of the birds, and the people, who live there.

A Suite of Similarities

Scientists have found that the urban birds that can hang on in built environments tend to have a lot in common. In 2023 a group of more than 50 scientists from research institutions spanning the U.S. to Colombia to Switzerland to Australia conducted a study of more than 5,000 bird species in urban areas around the world. Using data from the Cornell Lab of Ornithology’s eBird program, the group analyzed birder checklist submissions from 379 cities across 48 countries and discovered that birds in urban areas tend to be smaller, eat a wider variety of foods, lay fewer eggs, and forage over smaller areas than their counterparts in rural areas. Their research, published in Nature Communications, referred to this package of characteristics as “urban trait syndrome.”

“Cities tend to select for certain kinds of traits. In urban areas, for example, you don’t have species that will forage over large areas, because species that forage more broadly are more likely to encounter a vehicle or building that could lead to mortality,” says Frank La Sorte, a coauthor on the study who at the time was a Cornell Lab research associate.

La Sorte says urban pressures tend to favor bird species with similar traits that allow them to survive in urban areas and filter out species that lack those behaviors or characteristics.

Birds that thrive in urban areas also tend to have smaller eyes. Todd Jones, a postdoctoral fellow at the Smithsonian Migratory Bird Center, and colleagues compared birds that live within San Antonio, Texas, and birds of the same species that live outside of the city. They found that birds that were year-round residents in the city, such as Northern Cardinal and Carolina Wren, had eyes that were about 5% smaller than cardinals and wrens on the city’s outskirts. But the pattern didn’t hold true for migratory species. Painted Buntings and White-eyed Vireos had similar-sized eyes in the city and in rural areas.

The study, published in the journal Global Change Biology in September 2023, could help explain the devastating effect that light pollution has on migratory birds. City lights can disorient birds, which is why building collisions are a leading cause of bird mortality. Scientists estimate that up to 1 billion birds die each year after colliding with windows in the United States and Canada. Over time, the cardinals and wrens in cities may have evolved smaller eyes that are better at dealing with bright lights, whereas the migratory buntings and vireos may be more susceptible to the glare of the city lights.

“This study shows that residential birds may adapt over time to urban areas, but migratory birds are not adapting, probably because of where they spend the winter—they are less likely to have the same human-caused light and noise pressures,” says Jennifer Phillips, a Washington State University wildlife ecologist and study coauthor, in a press release. “It may make it more difficult for them to adjust to city life during the breeding season.”

Noise pollution also permeates urban areas, and that can impact how birds communicate. The low-frequency drone from cars, planes, and industry is a common sound in many cities. For some bird species, that noise prevents their songs and calls from being heard by other birds, because they vocalize at similarly low frequencies. Bird song is essentially drowned out by urban noise, a phenomenon that scientists call signal masking.

To be heard over the din, birds around the world tend to sing at higher frequencies in noisy environments, according to an analysis of 36 published papers conducted by scientists at the University of Quebec at Trois-Rivières. The 2016 research reported that on average birds in the study were shifting their song frequencies by 400 hertz—about the same difference as between the high C-sharp and E notes on a piano.

Frequency isn’t the only aspect of bird song that’s changing, according to a study of Northern Cardinals in Columbus, Ohio. The 2016 research—conducted by Desiree Narango, then a master’s student at Ohio State University, and Amanda Rodewald, senior director of Avian Population Studies at the Cornell Lab—found that cardinals within the city sang faster and for longer (and at higher frequencies) than cardinals in rural areas.

Around the same time, another study by Tulane University scientists found that White-crowned Sparrows in San Francisco Bay changed their tune to compete with urban noises. The study showed that San Francisco sparrows sing higher-frequency songs with faster trills and shorter whistles than rural sparrows. Then in a stunning shift, the sparrows changed their tune again. A follow-up study during the 2020 Covid-19 pandemic shutdown, when much of San Francisco was silenced, found that the sparrows responded quickly and started singing lower-frequency songs again. The study, published in the journal Science, suggests that bird song is flexible, and at least some species might be able to adapt.

But Elizabeth Derryberry—associate professor at the University of Tennessee, Knoxville, and lead author on the Science study—says that flexibility can only go so far.

“Singing louder or singing at higher frequencies has a threshold effect—birds can’t get infinitely louder,” says Derryberry. “Once noise reaches a certain level, there are limits to how far their signal can transmit, and that could affect the ability to acquire mates and defend territories.”

And even if males can change their tune to be heard and attract females, doing so does not always mean those higher-frequency singers are good mates. In 2018 Narango and Rodewald—the scientists who had studied urban cardinal song frequencies in Columbus, Ohio—turned their attention to the reliability of cardinal song as a signal of mate quality. In a study published in the journal Urban Ecosystems, they found that the cardinal males singing higher-frequency songs attracted mates, but not in high-quality habitats as their song might suggest. In other words, the changing song characteristics in response to urban noise can decouple what the song stands for. The male cardinals in the study had young that were in poorer condition, in part due to poorer habitat.

Additional research by Rodewald on cardinals has shown that the same kind of decoupling may be occurring with plumage brightness.

Birds obtain the bright yellows, reds, and oranges in their feathers from carotenoids in the foods they eat. Natural food sources high in carotenoids are also a rich source of antioxidants with immune-boosting properties, so birds with bright plumes are typically in better condition—thus brightness can be a signal of male quality. But in the eastern United States, many urban areas are filled with non-native honeysuckle shrubs. Honeysuckles provide birds with a source of carotenoids, but they are also very nutrient poor. Ornithologists refer to honeysuckle berries as junk food for birds, high in sugar and low in essential fats and nutrients.

In a 2011 study published in the journal Ecology, Rodewald and colleagues found that cardinals with access to honeysuckle berries in urban areas had brightly colored plumage, but those bright plumes didn’t translate to higher reproductive output.

“In urban areas,” says Rodewald, “the brightness of male Northern Cardinals stops being an honest signal of male quality.”

On the other hand, less brightly colored birds in urban areas may be in better condition than their plumage suggests. Urban areas have an abundance of birdseed—which is carotenoid poor, but nutrient dense. In both cases, Rodewald says, plumage coloration no longer signals male quality.

Beyond cardinals, research shows that the overall worldwide trend among urban birds is toward the development of duller plumage—a phenomenon scientists call “urban dullness.” The trend appears to be driven by pollution from heavy metals, such as cadmium and lead. Heavy metals can decrease the amount of carotenoids produced by plants, which via the food chain could reduce the availability of carotenoids for birds—resulting in less bright birds. In Belgium, for example, Great Tits that live around heavy-metal sources such as industrial facilities have duller yellow plumage than rural tits, according to a 2020 study.

Over time these pressures from air pollution, noise pollution, and light pollution add up. The bird species that can’t adapt to urban life disappear, leaving behind birds that sound and look similar.

“You end up with a smaller set of species that can survive,” says La Sorte, “resulting in less biodiverse cities.”

Yet hundreds of species can be found breeding in urban areas, and every spring and fall millions of birds migrate through U.S. metropolises, compelling many conservationists and scientists to look for ways to make cities more bird friendly.

“Cities present many challenges to birds,” Rodewald says, “but that doesn’t mean that cities are a lost cause when it comes to wildlife conservation.”

What Cities Can Do for Birds

To document the value of cities to bird conservation, a team of scientists from the Cornell Lab, Auburn University, and Rutgers University embarked on a study published last year that combined eBird checklists in the U.S. with lists of endangered bird species, critical habitat designations for endangered species, and 2010 census data. They discovered that birds listed under the Endangered Species Act (such as Piping Plover, Wood Stork, and Kirtland’s Warbler) can be found living in or migrating through 81% of urban areas (defined as cities with populations of more than 50,000 people).

“Our results show that cities can play an important part in conserving wildlife,” says La Sorte, a coauthor on the study.

In fact, cities can provide unique opportunities for the reintroduction of some endangered species, especially where reintroduction may be too fraught in their native habitat. In New Zealand, habitat loss and introduced predators took a toll on the New Zealand Kaka, an endangered parrot. The city of Wellington, with its large network of native forest patches, proved to be a good place to reintroduce the species. In these urban parks, officials could offer the parrots nectar and parrot pellets inside fenced areas that excluded predators.

City parks don’t need to be big to provide useful habitat for birds. In another study using eBird data that was published in September 2023, La Sorte and colleagues found that collections of small urban parks can support higher species richness than larger urban parks. The study suggests that’s because migratory birds are more likely to turn up at several smaller parks scattered across an urban area.

“Even small parks are beneficial,” says La Sorte, “because migratory birds are able to capture some resources and that will allow them to continue their journey or find better stopover habitat.” The migratory birds I spotted in Bryant Park were taking a break in what little refuge was available and hopefully continuing to make their way south. But there are more benefits to city parks, green spaces, and trees in urban areas than migratory bird habitat. Several medical studies in big cities have shown that trees can have health benefits for people—such as providing relief from urban heat.

The concrete, pavement, and steel of cities absorb heat during the day and release it at night, creating what scientists call urban heat islands. The U.S. Environmental Protection Agency has found that temperatures in these urban heat islands can get up to 22°F degrees hotter than surrounding suburban and rural areas, increasing the risk of heat exhaustion, heat stroke, and exacerbated heart and respiratory problems for sensitive populations.

“Heat is the number-one killer [of people] of all the weather phenomena,” said Eleni Myrivili, global chief heat officer of the United Nations and Arsht-Rock Resilience Center, at the New York Times Climate Forward Summit. “The best thing for cities is to bring nature in.”

The EPA found that planting native trees can significantly reduce urban temperatures and ameliorate the impacts of urban heat islands on human health and well-being.

“The solution is pretty straightforward—plant trees,” says Roxanne Bogart, coordinator for the Urban Bird Treaty program at the U.S. Fish and Wildlife Service. “It’s so important for people and wildlife.”

But unfortunately, in the United States access to green space is not equitable.

“Many of the people living in low-income neighborhoods have a higher percentage of people of color and immigrants with little access to green spaces,” says Marilú Lopez-Fretts, project leader for the Cornell Lab’s Celebrate Urban Birds project. According to the Trust for Public Land, one in three Americans does not have access to green space within a 10-minute walk of their home.

“When you lack green space,” explains Tykee James, president of D.C. Audubon in the nation’s capital, “you lack an area for outdoor recreation. And that outdoor recreation can be as simple as sitting on a park bench or sharing a meal or going on a walk. When that individual person doesn’t have access to the benefits of nature, those effects can lower a person’s lifespan.”

James says that communities without access to green space are more likely to suffer the adverse effects of urban heat, air pollution, noise pollution, and have poorer mental health. And he wants to fix that. D.C. Audubon is joining dozens of other organizations in support of the Outdoors for All Act, a bipartisan bill introduced in Congress by Senators Susan Collins and Alex Padilla in February 2023. The act seeks to codify the existing Outdoor Recreation Legacy Partnership program to ensure that funding cannot be diverted and is by law available for disadvantaged communities to create and restore much-needed green spaces.

Since the program began in 2014, the ORLP has been able to grant funds in only four years. But in years that funding was granted, more than 80 parks were created or restored across the U.S. The program, when funded, “has been tremendous in its ability to deliver federal dollars in low-income communities to upgrade or create parks,” says James.

In California, ORLP funds were used to turn a brownfield into a park with trails, boardwalks, and picnic areas for residents of northeast Los Angeles.

“Passing the Outdoors for All Act is essential for getting money to communities where they need it most,” says James.

In addition to dollars, both James and the Cornell Lab’s Lopez-Fretts agree that nature equity starts with listening.

“One key to building equitable green spaces is to engage with affected neighborhoods,” says Lopez-Fretts. “Work to improve the relationship, develop trust, and work together to create an action plan and a vision guided by the community.”

In New Haven, Connecticut, the Urban Bird Treaty program is working with local communities to restore urban green spaces that will improve water quality and provide better access to nature for people in nearby neighborhoods, while also providing habitat for migratory birds. The New Haven initiative also created a Green Job Corps to provide jobs and educational opportunities for disadvantaged youth.

“It’s collaborations like these,” says Bogart, “that create meaningful community engagement for people and provide habitat for birds.”

The key, says the Cornell Lab’s Rodewald, is to look for synergies in creating healthy habitats for birds and people.

“There is a lot to be said for the win-win conservation strategies and creating healthy urban environments that will benefit people as well as wildlife,” Rodewald says. 

From the Winter 2024 issue of Living Bird magazine. Subscribe now.

Perhaps no species of owl is as superbly adapted for hunting in snow as the Great Gray.

Found throughout the boreal forests of the Northern Hemisphere, Great Gray Owls dine primarily on small mouselike rodents called voles. In winter, voles retreat to tunnels deep under the snow—but that doesn’t stop Great Grays. Hunting from an exposed perch, an owl listens intently for its target, then swoops down from above, punching through the crust of snow with its long, powerful legs. Able to reach prey almost 18 inches below the surface of the snow, Great Gray Owls have been known to penetrate snow crusts thick enough to support a 175-pound person.

What hasn’t been clear, despite decades of research about Great Gray Owls, is how they do it—how do Great Grays hunt prey animals no longer than a ballpoint pen, which they can’t see, using only faint burrowing sounds more than a foot under the snow to guide them in plunging strikes with surgical precision?

Some intriguing new hints arrived recently via quirky research conducted by an unlikely pair of scientists. One, a California biologist who had spent most of his career studying the sounds made by hummingbird feathers, had long dreamed of working with owls; the other, a Canadian expert on owl field biology, had always wanted to study sound.

In their study, the researchers explored how Great Gray Owls use a set of finely tuned adaptations for gathering sound and localizing its source in deep snow. The Great Gray Owl’s facial disc, a bowl-shaped circle of feathers that frames its face, is the largest of any owl species, collecting and directing even the softest sounds from the environment toward its ears. And like other owls that hunt by sound, its ears, hidden under feathers, are asymmetrical. A higher ear opening on one side than the other enhances its ability to pinpoint a sound’s precise location.

To test the hunting-by-hearing capabilities of Great Grays, the researchers used an array of microphones buried under the snow to carry out a complex and unique set of experiments in the cold of Manitoba. Their research, published in the journal Proceedings of the Royal Society B in November 2022, uncovered new hints about the weird ways snow muffles and distorts sound—and the Great Gray Owl’s incredible ability to hear a vole hidden in the snow, which it turns out depends largely on the owl’s unique feathers.

Two Unlikely Experts Team Up

“I’m a hummingbird biologist. I know this much about working with owls,” admits Chris Clark, holding up his thumb and pointer finger with a tiny gap between them.

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Clark, a biology professor at the University of California, Riverside, began his career studying the mechanical sounds hummingbirds make with their feathers during display flights. About 14 years ago, he became fascinated with the opposite concept—how some birds (especially owls) minimize the noise they’d otherwise naturally produce in flight. He initially struggled to get any owl field research off the ground, but in 2021, he was contacted by a nature documentary crew making a film about animal sounds. And, the filmmakers mentioned, they were also working with a Great Gray Owl expert in Manitoba.

That expert was Jim Duncan. Duncan has been studying Great Grays for almost four decades, and after he retired as the director of Manitoba’s fish and wildlife agency in 2018, he started his own nonprofit organization, Discover Owls, focused on research, outreach, and conservation. Duncan recalls when, as a PhD student at the University of Manitoba, he conducted his first research on Great Gray Owls and spent the night in a snow hut called a quinzhee. On a bitterly cold February night at the Taiga Biological Station in eastern Manitoba, Duncan realized how snow muffled outside sounds.

“You don’t hear somebody walking up to your quinzhee until they’re right outside,” he says. “So it just became this nagging question in my mind: What sounds are these owls hearing, and how are they using them to catch food?”

The focus of his PhD dissertation was elsewhere, and he lacked the training and equipment necessary to pursue that question, so he set the question aside— until, over 30 years later, the documentary crew introduced him to an expert on bird flight and sound in California.

Soon, Clark paid for a plane ticket out of his own pocket, packed every piece of warm clothing he owned along with his acoustic analysis equipment, and headed for Manitoba. On the surface, the goals of their collaboration were simple: to test how snow might absorb and distort the sounds of voles and how that might affect Great Gray Owl hunting strategies.

“Owl Ears” vs. “Mouse Ears”

Great Grays use stealthy flight to surprise their unsuspecting prey. Owls in general are known for flying almost silently, but intriguingly, Great Grays take those traits to the extreme. Of all owl species in the world, Great Grays have the longest comblike serrations on the leading edges of their wings, and the thickest velvety coating on their flight feathers—both evolutionary adaptations for silent flight that reduce wing noise to almost nothing.

There are, says Clark, two primary hypotheses to explain why owls evolved to fly quietly: “What I call the owl-ear hypothesis and the mouse-ear hypothesis.” The owl-ear hypothesis is that owls fly quietly to avoid interfering with their own ability to detect prey by sound; the mouse-ear hypothesis is that they’re trying to avoid being detected by potential prey.

“Although these hypotheses aren’t mutually exclusive,” explains Clark, “there are some cases where they make different predictions, and the number-one case is when the environment itself blocks sound,” such as when there’s a thick layer of snow on the ground. The owl-ear hypothesis suggests that a snow-hunting owl should have especially well-developed quieting features, so that it can hear its muffled prey over the sound of its own wings. Under the mouse-ear hypothesis, however, quieting features would be less important, because the snow would provide the owl with natural stealth.

But snow does more to sound than simply dampen it. A snowpack is surprisingly complex, part ice and part air, with different densities at different depths—all affecting the transmission of sound. Low and high sounds pass through snow in different ways, and because of the different speeds at which sound travels through air and ice, snow might even refract sound, bending it so that it seems to come from a different location than its actual source.

Heading to a site 60 miles northeast of Winnipeg, where Duncan knew owls hunted, he and Clark located fresh plunge holes from Great Grays pursuing voles. They dug into the snowpack and slipped a waterproof speaker underneath, playing white noise or recordings of voles digging. Then, they pointed an acoustic camera that Clark lugged from his UC–Riverside lab at the snow. An acoustic camera uses an array of 40 microphones to localize where a sound appears to be coming from, then superimposes this apparent source location on a camera image.

Working with electronic equipment in temperatures as low as –16°F presented some difficulties: “I’ve only experienced cold temperatures like that a couple of times before in my life,” says Clark, the Californian. Both the laptop he used to run the acoustic camera and the speakers playing the sounds repeatedly froze up and stopped working, limiting the number of trials they were able to do. Ultimately, Clark and Duncan were only able to complete six successful trials with the buried speaker.

But even those six trials were enough to provide some intriguing new insights into the challenges a Great Gray Owl faces when hunting in winter—and how it overcomes those challenges.

Refraction, Attenuation, and Acoustic Mirage

The results from the acoustic camera provided detailed data about how snow impacts sound in two ways: refraction and attenuation.

In this case, attenuation is the term for the way a blanket of snow muffles sounds. Clark and Duncan’s results showed that low-frequency sound is much less affected than high-frequency sound, making Great Gray Owls’ enormous facial discs—especially well-suited for gathering low-frequency sound—an ideal adaptation for hunting in deep snow. But the acoustic camera also confirmed the second, weirder way snow affects sound. Sound is indeed bent as it travels through the snowpack, shifting its apparent source by as much as five degrees relative to the actual position of the buried speaker— a phenomenon that Clark and Duncan dubbed an “acoustic mirage.”

This effect is minimized when you listen from directly above the sound’s true source, which helps explain a distinctive aspect of Great Gray Owl hunting behavior: hovering. Just before an owl plunges into the snow, it often hovers in midair for a few moments, frenetically beating its wings. This tactic likely gives an owl a chance to lock in on a vole’s actual position from the point where the acoustic mirage is minimized. Some fish-eating birds—such as ospreys, kingfishers, and gannets—prefer to strike straight down at their underwater prey for similar reasons, although they’re dealing with water bending light instead of bending sound.

Clark sees two possible ways that these snow sound effects could play into Great Gray Owl extreme adaptations for quiet flight. On the one hand, perhaps the owls’ quieting features on their wing feathers specifically suppress low-frequency sound, ensuring that sound from an owl’s own wings doesn’t interfere with its ability to hear the low-frequency digging sounds of the voles. Or, perhaps (and this is the scenario he thinks is more likely) they may be specifically suppressing sound during hovering, so as not to interfere with an owl’s ability to target its prey accurately during this crucial final moment.

“When they’re hovering, you can see the feathers in the back of the wing lifting up. That’s an indication that part of the wing is stalling, which is when the air stops flowing smoothly over the surface of the wing and starts to form a lot of turbulence,” says Clark. Turbulence creates sound, which these wing features could have evolved to counteract. Other birds that hover while hunting, such as kestrels and harriers, have velvety wing coatings like owls.

Both of these possibilities are consistent with the owl-ear hypothesis, not the mouse-ear hypothesis. Neither explanation for the owl’s quieting adaptations is about helping the owl sneak up on voles, which can’t hear the owl coming regardless, buried as they are under a sound-attenuating blanket of snow. Instead, according to Clark and Duncan, these adaptations ensure that Great Grays can hear voles over the sound of their own wingbeats as they lock onto their unseen prey’s position.

Katherine Gura, a researcher at the Teton Raptor Center in Wyoming and expert on Great Gray Owl ecology, who was not involved with this acoustics study, was “thrilled” when she read Clark and Duncan’s paper.

“This work serves as an excellent example of the fascinating questions we can answer by merging a strong knowledge of the physical properties of snow with wildlife ecology,” she says. “By testing how sound travels through the snowscape and linking those findings to Great Gray Owl foraging strategies and morphology, this study begins to unravel how this species evolved its unique winter behavior and traits.”

Gura says that Clark and Duncan’s research is a crucial first step for further studies on whether these snow-hunting acoustic adaptations of the Great Gray Owl can hold up over time, as the Earth continues to warm—and snowy winters melt away.

“This work opens the door for better understanding how changing snow regimes potentially will affect Great Gray Owls and other species that rely on subnivean [under the snow] prey,” says Gura. “Their ability to forage—and ultimately persist—in a changing world remains unknown.”

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