If you weren’t outside enjoying the sun on Wednesday, April 19, you were probably milling around Penn Pavilion, a can of LaCroix in hand, taking in the buzz and excited chatter of students presenting at the 2023 Fortin Foundation Bass Connections Showcase.
Open floor presentations at the 2023 Bass Connections Showcase
This annual celebration of Bass Connections research projects featured more than 40 interdisciplinary teams made up of Duke faculty, graduate students, undergraduate students, and even partners from other research institutions.
Research teams presented posters and lightning talks on their findings. You might have heard from students aiming to increase representation of women in philosophy; or perhaps you chatted with teams researching physiotherapy in Uganda or building earthquake warning systems in Nepal. Below, meet three such teams representing a wide variety of academic disciplines at Duke.
Building sustainable university-community partnerships
As Bass Connections team member Joey Rauch described, “this is a poster about all of these other posters.” Rauch, who was presenting on behalf of his team, Equitable University-Community Research Partnerships, is a senior double-majoring in Public Policy and Dance. His interest in non-profit work led him to get involved in the team’s research, which aims to offer a framework for ethical and effective university-community research collaboration – exactly what teams do in Bass Connections. The group looked at complicated factors that can make equitable relationships difficult, such as university incentive structures, power dynamics along racial, socioeconomic, and ethnic lines, and rigid research processes.
Senior Joey Rauch with his team’s 2nd-place poster!
Along the lines of rigid research, when asked about what his favorite part of Bass Connections has been, Rauch remarked that “research is oddly formal, so having a guiding hand through it” was helpful. Bass Connections offers an instructive, inclusive way for people to get involved in research, whether for the first or fourth time. He also said that working with so many people from a variety of departments of Duke gave him “such a wealth of experience” as he looks to his future beyond Duke.
For more information about the team, including a full list of all team members, click here.
Ensuring post-radiation wellness for women
From left to right: seniors Danica Schwartz, Shernice Martin, Kayle Park, and Michelle Huang
The project has been around for three years and this year’s study, which looked at improving female sexual wellness after pelvic radiation procedures, was in fact a sister study to a study done two years prior on reducing anxiety surrounding pelvic exams.
As Huang described, graduate students and faculty conducted in-depth interviews with patients to better understand their lived experiences. This will help the team develop interventions to help women after life events that affect their pelvic and sexual health, such as childbirth or cancer treatment. These interventions are grounded in the biopsychosocial model of pain, which highlights the links between emotional distress, cognition, and pain processing.
For more information about the team, including a full list of all team members, click here.
From dolphins to humans
Sophomores Noelle Fuchs and Jack Nowacek were manning an interactive research display for their team, Learning from Whales: Oxygen, Ecosystems and Human Health. At the center of their research question is the condition of hypoxia, which occurs when tissues are deprived of an adequate oxygen supply.
Sophomores Noelle Fuchs and Jack Nowacek
Hypoxia is implicated in a host of human diseases, such as heart attack, stroke, COVID-19, and cancer. But it is also one of the default settings for deep-diving whales, who have developed a tolerance for hypoxia as they dive into the ocean for hours while foraging.
The project, which has been around for four years, has two sub-teams. Fuchs, an Environmental Science and Policy major, was on the side of the team genetically mapping deep-diving pilot whales, beaked whales, and offshore bottlenose dolphins off the coast of Cape Hatteras to identify causal genetic variants for hypoxia tolerance within specific genes. Nowacek, a Biology and Statistics double-major, was on the other side of the research, analyzing tissue biopsies of these three cetaceans to conduct experiences on hypoxia pathways.
The team has compiled a closer, more interactive look into their research on their website.
And when asked about her experience being on this team and doing this research, Fuchs remarked that Bass Connections has been a “great way to dip my toe into research and figure out what I do and don’t want to do,” moving forward at Duke and beyond.
For more information about the team, including a full list of all team members, click here.
Amid fracturing arctic ice shelves, late September tempests, floods, droughts, jumping wildfires, a few decades of quick extinction and species blinking out like the quiet collapse of distant supernovae, our climate crisis has begun to displace humans en masse.
68.5 million people were forcibly displaced by climate change and disasters in 2017. By 2021, that number grew to 89.3 million people. In 2022, we reached 100 million.
In a series of articles for the San Francisco News entitled “The Harvest Gypsies,” John Steinbeck described the 1930s Dust Bowl migrants in California’s Central Valley, uprooted by drought and crumbling wheat, then later novelized in the American classic Grapes of Wrath.
Steinbeck wrote, “The new migrants from the dust bowl are here to stay. They are the best American stock, intelligent, resourceful; and, if given a chance, socially responsible. To attempt to force them into a peonage of starvation and intimidated despair will be unsuccessful. They can be citizens of the highest type, or they can be an army driven by suffering to take what they need. On their future treatment will depend the course they will be forced to take.”
Co-sponsored by Duke Center for International Development (DCID) and the Center on Modernity in Transition (COMIT), the lecture is part of the larger Rural Transformations speaker series, highlighting rural perspectives in the discourse around development. This objective embodies COMIT’s research as well as their cognizance of “modernity as an age of transition towards a future world society—one that will emerge not through the universalization of any existing way of life, but rather through the sustained, creative, and complexly interacting contributions of all the diverse cultures and peoples of the world.”
The Dust Bowl, McLeman pointed out, is a quintessential example of climate migration, conjuring Dorothea Lange’s depression-era photojournalism and 8th grade US history. More recently, this phenomenon has been exemplified by hurricanes Katrina, Ike, Harvey, Irma, Sandy, Ida, Hugo, Andrew, Ian, and Maria (just to name a few) with similar, though smaller scale effects.
As McLeman and Bermeo acknowledged, climate-catalyzed movement is highly dependent on complex interactions between environment, society, economy, and politics, including a myriad of non-ecological factors like “land tenure, social networks, [and] access to government programs.”
Dr. Robert McLeman is a Professor of Geography and Environmental Studies at Wilfrid Laurier University in Ontario, Canada and is the author of Climate and Human Migration: Past Experiences, Future Challenges
Their research on the demographic composition and rates of climate-migration answers a number of questions: who is disproportionately affected by climate change? Who is migrating? And who is participating in policy decisions?
December 2022, the Biden Administration announced a $135 million investment for relocation and adaptation planning for Native American tribes severely impacted by environmental crises, such as “coastal and riverine erosion, permafrost degradation, wildfire, flooding, food insecurity, sea level rise, hurricane impacts, potential levee failure and drought.”
In less than a lifetime, one such tribe, the Jean Charles Choctaw Nation in Terrebonne Parish, Louisiana, witnessed nearly their entire island sink into swampy silt.
On their tribal website, they write: “For our Island people, [Isle de Jean Charles] is more than simply a place to live. It is the epicenter of our Tribe and traditions. It is where our ancestors survived after being displaced by Indian Removal Act-era policies and where we cultivated what has become a unique part of Louisiana culture.
Today, the land that has sustained us for generations is vanishing before our eyes.”
Dr. Sarah Bermeo is a political economist, associate professor of Public Policy and Political Science in Duke’s Sanford School, and author of Targeted Development.
Climate migration in America, however, is not contained within and between states. In the past decade alone, Bermeo’s research points to a significant increase in migration from Central America to the US as well as novel patterns of family unit migration to the southern border (as opposed to a predominantly individual, male demographic in previous years). She attributes two recent droughts to this out-migration, disproportionately displacing rural communities whose livelihoods are integrally tied to subsistence farming and year-to-year crop yield.
“People leave their homes because of climate but leave their countries for other reasons,” Bermeo explained. A large percentage of climate-migration is “inter-state,” i.e. a rural coastal community is forced to move inland (but still within their country) because of dangerous erosion.
“Central America’s choice: Pray for rain or migrate. Ravaged by drought, farmers in rural Honduras and Guatemala live on the edge of hunger,” reports NBC News.
In Central America, however, there is a distinct relationship between the incidence of drought and violence. Environmental stress has catalyzed a mass exodus from rural areas, increasing urbanization, yet these cities (particularly those in Honduras, Guatemala, and El Salvador) often rank globally among the most violent, based on year-to-year per capita homicide rates.
With high levels of urban corruption and gang affiliation, it is often difficult for rural “outsiders” to find employment in the cities, leaving them unable to compensate economically for a season of crop failure. This conflict is further exacerbated by large proportions of young workers in these populations.
Despite deep-seated political polarization, climate-migration is adaptive.
McLeman described migration generally as “neither good nor bad… something that people sometimes do and always have done… [But] in North America, we lose sight of the fact that it is normal human behavior… it’s the circumstances under which it occurs that creates the challenges.”
When migration is voluntary, when people have access to social safety nets, are able to remit money to their families back home, and to mobilize legally across borders, migration is beneficial for the migrant, the migrant’s family, and the receiving community (which often benefits by filling labor demands). Often, the ramifications of immigration portrayed in the media (crime, destitution, etc.) are exacerbated by the lack of legality, social networks, and “gray markets.”
Bermeo acknowledged that the most effective mechanisms of decreasing undocumented migration are those that increase legal pathways. Historically, when the US has increased the number of visas allocated to Central American immigrants, illegal immigration subsequently decreased.
The panelists agreed: in order for both the migrating and receiving communities to benefit, we must prioritize the dignity of migrating individuals.
Though conversations surrounding climate change feel threateningly existential, Bermeo and McLeman described ways in which climate adaptation can be manageable. When migrants and rural communities are excluded from conversations and subsequent policy-making, not only do they benefit less from the proposed and funded interventions, but other communities (perhaps at less imminent risk from climate change) will still suffer from this missing insight.
Here, I return to the Jean Charles Choctaw Nation. Despite the appearance of a successful relocation project, the tribal council released a press statement in 2022, condemning the state of Louisiana. Elder Chief Albert Naquin spoke on the issue:
“If you believe that the resettlement of Isle de Jean Charles was successful, you’re headed in the wrong direction.” The memo added that, “Moving people while trampling upon our Tribe’s inherent sovereignty and rights to self-determination and cultural survival must not be viewed as a ‘success’ for future public climate adaptation investments.”
Dr. Kerilyn Schewel is a lecturing fellow at the Duke Center for International Development. She has received an award from the Social Science Research Council for her research project titled “Rural Development and the Capability to Stay.”
The mass movement of climate-migrants, from Indigenous to rural communities, represents a loss of autonomy, of land integral to identity, and often of home.
Still, Schewel’s Rural Transformation project advocates for the prioritization of these communities, rejecting the notion of passive policy-making and, instead, endorsing their active participation. Her project is indicative of how we must approach climate change adaptation: with empathy, education, and inclusion.
In a conversation with DCID, Schewel put it best: “[R]ural places are often treated as an afterthought… Some of the most promising advances in sustainable and equitable development are taking place in rural contexts, where a diversity of actors are striving to transform food systems, incorporate local knowledge, strengthen climate resilience, and widen participation in the development process.”
The DCID article ends with key insights from Schewel that encompass the Climate Change, Adaptation and Migration discussion and bear repetition: “As more focus is going towards migration, this is a project that will take very seriously the constraints on rural livelihoods and the motivations of migrants who leave rural places, while offering forward-looking solutions to advance our understanding of what it would mean to build more sustainable and flourishing rural futures.”
Clockwise: Jonathan Shaw, Adam Kosinski, Natalie Farris, and Kavya Menke looking at bryophytes on a log.
On a bright Sunday afternoon in April, I did something I had never done before. I went for a walk in the woods specifically to look for mosses. No, that’s not strictly true — we were looking for bryophytes. I learned, among other things, that not everything I had always called moss was really moss at all. (The word bryophyte comes from ancient Greek components and literally means “moss plant.”)
A patch of moss on the Al Buehler Trail. Moss is one type of bryophyte; liverworts and hornworts are the two others.
The walk was organized by Wild Ones, an undergraduate nature club I’m involved with. Biology Professor Jonathan Shaw, Ph.D., and Blanka Aguero, data and collections manager in the Duke University Herbarium, volunteered to teach a group of undergraduates about mosses and other bryophytes on the Al Buehler Trail adjacent to the Duke golf course.
Jonathan Shaw and members of the Wild Ones holding moss. Mosses, liverworts, and hornworts together represent the bryophytes.
Bryophytes (which include mosses, liverworts, and hornworts) represent one of several large groups of terrestrial plants. Other groups include angiosperms (flowering plants), gymnosperms (cone-producing plants like conifers and ginkgos), pteridophytes (vascular, spore-producing plants including ferns and horsetails), and lycophytes (an ancient group with about 1200 surviving members). According to Shaw, bryophytes are “the second biggest group after the flowering plants, but the flowering plants are an order of magnitude more diverse.” Aguero says that North Carolina has 462 moss species, 211 liverworts, and 7 hornworts.
Zach Pracher (Wild Ones member) and Blanka Aguero looking at bryophytes on a log.
Unlike the other terrestrial plant groups, bryophytes are nonvascular, meaning they lack the water transport tissues that other plants use. Without vascular tissue and without lignin for support, bryophytes can’t grow very big because they have no way to efficiently move water from their base to the rest of the plant. Instead, they grow close to the ground and absorb water directly from the environment into their cells.
Despite their preference for damp habitats, bryophytes can live for a long time without water. Some plants (like cacti) survive droughts by storing water, but bryophytes have a different strategy. They go into a state of dormancy, or suspended animation, and simply wait. Then, when it next rains, “they go hog-wild, photosynthesizing again in minutes,” Shaw says.
So if bryophytes don’t rely on constant moisture to survive, why do they like it so wet? Water, as it turns out, isn’t just important for hydration. Bryophytes rely on it to reproduce as well.
“Mosses are the amphibia of the plant communities,” Shaw says. Just as many amphibians can live on land but must return to the water to reproduce, bryophyte sperm has to “swim” to an egg cell to fertilize it. Therefore, they need water in order to reproduce, but they don’t need much. It could be mist from a splashing waterfall or a puddle in the woods or rainwater trickling down a tree. It could even be dew.
Moss on a tree trunk. Bryophytes can grow in a wide range of habitats across the world.
The day was warm and sunny, but the ground was dotted with puddles from recent storms. Armed with small hand lenses, we set off down the trail, stopping periodically to scrutinize tree bark, fallen logs, and thick patches of moss on the forest floor.
You need not travel far to find bryophytes. Mosses and their cousins colonize all sorts of hidden nooks: damp logs, trailside divots, tree bark, riverbanks, forgotten corners of backyards. Compared to seed-producing plants, bryophytes tend to have larger geographic ranges, perhaps in part because spores disperse more easily and because bryophytes can survive dry spells. Shaw estimates that about 75% of the moss species found in North Carolina are also found in Europe, and some of them are found in Asia as well.
Atrichum moss viewed through a hand lens. Note the thin line down the middle of each leaf. That line is a midrib and is one feature that sets mosses apart from liverworts.
We learned that most mosses have a midrib in the middle of each leaf, whereas liverworts have no midrib.
“A liverwort,” Shaw explains helpfully, “is like a moss, but it’s a liverwort.”
Liverworts are relatively flat in comparison to mosses because their leaves are in two parallel rows, whereas mosses tend to have a more spiral shape, with leaves emerging from all sides of the stem. The flat appearance of liverworts explains why they are sometimes called scale mosses. Another feature to consider if you’re trying to distinguish mosses and liverworts is the presence of lobed leaves, or leaves with protuberances off the main leaf (think of maple or oak leaves, for example). Some liverworts (but not all) have lobed leaves, but no mosses do.
A liverwort (main image) and the same liverwort viewed through a hand lens (top right). Liverworts and mosses can look very similar, but a hand lens makes it easier to spot the differences between them. Note the relatively flat appearance of the liverwort leaves compared to moss leaves, which tend to grow in a spiral fashion around the stem.
Aguero and Shaw both point out that the features we use to visually distinguish bryophytes aren’t necessarily the same features that officially set mosses and liverworts apart. The main difference between mosses and liverworts involves differences between their sporophytes.
Frullania is a genus of liverworts that forms dark patches, like the spots on this tree. If you see patches like these, Aguero says, they are “invariably” Frullania liverworts.
“It’s not true that if you’ve seen one moss, you’ve seen them all,” Shaw says. They’re small, yes, but they are not all the same.
We looked at one particularly lush patch of moss in the Bryoandersonia genus, named after a Duke professor. If you’re trying to identify trees, Shaw says, you might start with features like whether the leaves are broad or narrow and whether the tree is shrubby or not. With mosses, on the other hand, one of the first questions to ask is whether it’s pleurocarpous or acrocarpous. Pleurocarpous mosses, such as the Bryoandersonia we looked at, tend to have highly branching stems and grow in sprawling patches. The stems of acrocarpous mosses, meanwhile, have little or no branching and grow mostly vertically, often forming tight clumps.
Kavya Menke (Wild Ones member) examining a thallose liverwort we found by a stream.
After learning about patches of Frullania liverworts on trees from Aguero, we examined a large clump of liverworts growing beside a stream. Unlike the other liverworts we’d seen, this was a type of thallose liverwort, set apart from so-called leafy liverworts by the presence of thallus (a ribbon-like structure) instead of leaves. We also had the chance to smell it. Interestingly, liverworts also have a distinctive smell, sharp and earthy. The scent can be so strong that you might sometimes smell liverworts before you see them.
A thallose liverwort in the genus Conocephalum. Thallose liverworts are characterized by thalli (plural of thallus) instead of leaves. The other liverworts we saw were leafy liverworts. Photo by Adam Kosinski.
According to Shaw, the term liverwort dates back to when botany and herbal medicine were considered largely the same. The so-called Doctrine of Signatures is the long-held idea that plants’ physical features reveal their medicinal uses. Thallose liverworts were thought to resemble livers and were used to treat ailments of the liver, hence the name. Similarly, the walnut looks rather like a brain and was used to treat mental illness, while the Dutchman’s breeches flower (the white flowers are said to resemble pants) was used for sexually transmitted diseases.
Aguero says that some liverworts do contain chemicals with antimicrobial properties, but she advises people not to eat liverworts.
Moss sporophytes, which release spores into the air. (Top right: close-up through hand lens.) The sporophytes are the only part of a bryophyte that are diploid (containing two sets of chromosomes instead of one). The trees in the background are also diploid; most plants (with the exception of bryophytes) are diploid during most of their life cycle. Photos by Adam Kosinski.
Near the end of our walk, we found something we’d been keeping an eye out for but hadn’t yet seen: moss sporophytes. Bryophytes have a unique life cycle. Most of the time when we see a plant or an animal, it is diploid, meaning each cell contains two full sets of chromosomes (one from each parent). Every human cell, for instance, contains 46 chromosomes—with the exception of female egg and male sperm cells, which contain only 23. Cells that have only one set of chromosomes (like human egg and sperm cells) are called haploid. Plants undergo alternation of generations, meaning that one phase in their life cycle is haploid and one is diploid. In the case of most plants, the dominant and most conspicuous part of the life cycle is the diploid phase, but bryophytes are different. The fuzzy green carpets of moss we see are made of haploid cells, while the diploid phase is short-lived and only appears during reproduction. In mosses, the diploid phase (also known as the sporophyte) resembles thin filaments emerging from the haploid bed of moss. These sporophytes release spores (the spores are haploid) that grow into the next generation of moss.
“I wish we could be like the moss spores and let the wind carry us,” said Kavya Menke, one of the undergraduates on the walk. “Cheaper than Uber.”
Clockwise: Wild Ones members Natalie Farris, Adam Kosinski, and Zach Pracher examining patches of Frullania, a liverwort genus.
Occasionally, I paused my own bryophyte observations to watch others watching bryophytes. I found myself wondering if people are similarly bemused when they see me standing in a swamp with binoculars or crouching down on the way to class to move an earthworm off the sidewalk. I am accustomed to the world of birding, and looking for creatures like dragonflies, snakes, and salamanders feels natural to me as well. But this was a delightful opportunity to enter a world in which I had little to no experience: the shady, damp world of the bryophytes.
Adam Kosinski taking a close look at a bryophyte specimen placed on a log.
If you make a habit of going on walks with birders, you may spend a lot of time waking up before dawn, craning your neck upward, and straining to hear the alleged differences between a dozen kinds of short chirps. If you go out looking for snakes, you might spend a warm afternoon flipping over sun-warmed boards and scanning rocks and other basking spots. Searching for salamanders will likely involve scrutinizing wet soil, leaf litter, and ponds in early spring, possibly on a dark and rainy night. But searching for bryophytes is an experience all its own.
For one thing, you can go at any time of day and be equally successful, seeing as bryophytes neither crawl nor slither nor fly. You can also feel free to move as slowly as you wish. Aguero compares bryologists to lichenologists: “Moss people and lichen people work together frequently,” she says. “We walk similarly slowly.”
Blanka Aguero discussing bryophytes with students. Photo by Adam Kosinski.
You could walk the same trail a hundred times and see it a hundred different ways. You could focus on birds or earthworms or snakes, wildflowers or changing leaves, clouds or trees or rocks. The next time you are in the mood to explore a new world, consider taking a walk — either somewhere new or a path you’ve walked a hundred times before — and turning your attention to the wonderful world of the bryophytes. Pet the moss. Feel its springiness and dampness and softness. Run your fingers lightly over the thin sporophyte stalks and notice how they tickle your palm. Smell the liverworts. See the dark patches of Frullania on a tree trunk. Bryophytes are nearly everywhere. Look for them. Look at them. See them.
Bryoandersonia moss viewed through a hand lens. Photo by Adam Kosinski.
After a three-year hiatus caused by the COVID-19 pandemic, Duke’s student chapter of the American Society of Civil Engineers (ASCE) returned to the Carolinas in-person gathering. And they were in it to win it, taking home awards in four out of the five events in which they competed.
Duke sent seven Duke undergraduates to the symposium, which was hosted by The Citadel in Charleston, South Carolina: Leo Lee, Harrison Kendall, Arthur Tsang, Hana Thibault, Anya Dias-Hawkins, Sarah Bailey and Grace Lee.
When not going for gold, the students also attended business meetings and professional workshops related to the civil engineering profession.
(Left to right) Leo Lee, Harrison Kendall, Arthur Tsang, Hana Thibault, Anya Dias-Hawkins, Sarah Bailey, Grace Lee at The Citadel after the Symposium awards banquet.
Duke ASCE students also enjoyed networking with peers for the first time in years, meeting chapter members from other schools such as North Carolina Agricultural and Technical State University, North Carolina State University, The Citadel, Horry Georgetown Technical College, and Clemson University.
Sarah Bailey, Harrison Kendall, Anya Dias-Hawkins, and Hana Thibault before competing in the Quiz Bowl competition.
But when the lights came up, the gloves came off, and Duke’s students faced off against their peers in five competitions. Sophomore Anya Dias-Hawkins and junior Sarah Bailey earned third place for their efforts in the Geotechnical competition, where students were tasked with a real-life geotechnical design problem.
Juniors Grace Lee and Leo Lee along with senior Arthur Tsang won first place for their design in the Lightest Bridge competition, where popsicle bridges had to withstand a weight of 200 lbs.
Sophomores Anya Dias-Hawkins, Harrison Kendall and Hana Thibault also took home first place honors in the Freshmore competition, where students were tasked with designing an imaginary city. Lastly, Harrison Kendall won an individual award for his paper and presentation in the Daniel W. Mead Paper competition.
Arthur Tsang, Leo Lee, and Grace Lee standing on their winning Lightest Bridge design.
Duke ASCE is extremely excited to continue their efforts at the Carolinas symposium next year and hopes to send many more competitors. The group plans to compete in larger competitions such as Concrete Canoe next year at UNC Charlotte. With enough preparation, the students hope to advance to the national conference in 2024.
If you are interested in getting involved with Duke ASCE and/or competing in next year’s symposium, please email co-Presidents Sarah Bailey and Harrison Kendall at sarah.a.bailey@duke.edu or harrison.kendall@duke.edu.
Post by Harrison Kendall, civil engineering class of ‘25
Naturalist Tom Earnhardt on Black River in North Carolina. The forests around Black River are home to the oldest trees in eastern North America, 2,700-year-old bald cypresses. All photos courtesy of Tom Earnhardt.
There are many ways to think of North Carolina. It was the 12th U.S. state to enter the Union. It is bordered by Virginia, Tennessee, Georgia, and South Carolina. North Carolina’s capital city is Raleigh, and it has an estimated population of 10,698,973. These are all facts, but they tell only part of the story: the human side of it.
Naturalist Tom Earnhardt offers other ways to view North Carolina: the state contains the oldest forest in the eastern United States, with trees up to 2,700 years old. It has 17 river basins, and some of its rivers show evidence of fishing weirs used by indigenous tribes hundreds of years ago. And from the Atlantic coast in the east to the Appalachian mountains in the west, North Carolina is home to thousands of native plants, animals, and fungi. There are 3,000 species of moths alone in North Carolina, and “Every one is essential; not one is optional.”
“North Carolina,” Earnhardt says, “is still one of the most biodiverse and extraordinary places on the planet.”
A prothonotary warbler. Prothonotary warblers inhabit swamps and coastal rivers in North Carolina. They are one of only two warblers in America that nest in cavities.
Earnhardt is a naturalist, photographer, writer, and attorney. He wrote and produced the show “Exploring North Carolina,” a series of dozens of episodes about North Carolina’s biodiversity, geography, and history. Earnhardt recently visited Duke to speak at the Nasher Museum of Art.
One inspiration for his talk was the ongoing Nasher exhibit “Spirit in the Land,” an exploration of ecology, culture, and connection to the natural world. “Art in its many forms,” Earnhardt says, “tells a story of love, loss, and renewal.”
Black River in North Carolina.
Earnhardt has spent much of his career balancing caution and hope. We are facing environmental crises, including climate change and biodiversity loss. Earnhardt believes it’s important for people to know that, but he has put a lot of thought into how to get that message across. Earnhardt has learned that it can help to “tell it as though it was your best friend or brother who needed to hear an important story.” Science alone isn’t always enough. “To hear bad news of any kind is not easy,” Earnhardt says, “and people want to hear it from people they know, people they trust or can relate to.”
The stories he tells aren’t always easy to hear, but they are important. We need to know — whether on a local, state, national, or international scale — what exactly we stand to lose if we continue on a path of environmental destruction. Many species are becoming more scarce, Earnhardt says, “but we still have them.” They can’t be protected once they’re gone, but many of them are still here and can still be preserved. The goal for all of us should be to keep it that way.
North Carolina, Earnhardt says, is at “the epicenter of the temperate world.” The state has a range of climates and habitats. It marks the northernmost native range of the American alligator, while coniferous forests in the North Carolina mountains resemble boreal forests of the northern U.S. and Canada. North Carolina, according to Earnhardt, contains “whole ecosystems that other states only dream about.”
Eastern North Carolina is characterized by beaches, salt marshes, and other coastal ecosystems. Here you can find “wildflowers that grow in salty sand” and painted buntings, multicolored songbirds unlike any other in North America. On four occasions, he’s even seen manatees in North Carolina.
A male painted bunting, a summer resident on North Carolina’s barrier islands. Female painted buntings are bright green.
“Travelers from around the world vacation here and raise their families in the summer,” Earnhardt says—and he’s not talking about humans. Many shorebirds and sea turtles lay their eggs on North Carolina’s beaches. Human disturbance, including artificial lighting and crowded beaches, can put their babies in danger. Minimizing light pollution near beaches, especially during turtle nesting season, and staying away from nesting shorebirds can help.
A longleaf pine savanna in southeastern North Carolina.
Moving farther west, we can find savannas of grasses and pine trees. “You drive past this, and people go, ‘ho hum, a pine barren.’” To that Earnhardt says, “Look a little closer.”
White-fringed orchids, one of North Carolina’s 80 native orchid species. Earnhardt took this photo in the Green Swamp, a longleaf pine savanna nature preserve.
These pine barrens are home to some of North Carolina’s 80 species of orchid, like the white-fringed and yellow-fringed orchids. “Look at them from all angles,” Earnhardt urges, “because from up above it becomes a sunburst… for those who watch.”
A yellow-fringed orchid, viewed from the side.
Be one of those who watches.
A yellow-fringed orchid, viewed from above.
North Carolina rivers, forests, and swamps are also home to many wildlife species. Forests around Black River contain “huge buttresses of tupelo that hold the world together” and bald cypresses that have been alive for 2,700 years. The early years of these now-ancient cypress trees coincided with the fall of the Assyrian Empire and the establishment of the first emperor of Japan. Many centuries later, they are the oldest trees in eastern North America.
Cypress trees on Black River. Both tupelos and cypresses have buttresses at their bases to provide stability in the water.
They are also in danger. “If seas rise three feet,” Earnhardt says, “there will be enough pressure to flood these [trees]…. We could lose them.” But “they are worth saving.”
Still farther west are the Appalachian mountains, another biodiversity hotspot. North Carolina is home to 60 species of salamanders, many of which live in the mountains. The southern Appalachians and western North Carolina contain more salamander diversity than anywhere else on the planet. One species that lives here is the American hellbender, a two-foot-long denizen of mountainous streams.
Despite increasing human development, North Carolina is still rich in flora and fauna. “We have wild places,” Earnhardt says. North Carolina has more than 450 bird species, over 30 native pitcher plants, 20 freshwater turtles, and 38 snakes—“and they’re all good neighbors,” Earnhardt adds.
Venus flytraps in a longleaf pine savanna.
North Carolina has pink and yellow lady slippers and ten-foot-tall Turk’s Cap lilies; crayfish and thousands of mushrooms; native azaleas and insects that depend on them. It has Earnhardt’s “new favorite bird,” the swallow-tailed kite, and vultures, “the clean-up crew: not optional.” That’s a refrain throughout Earnhardt’s talk. “Nothing I’ve shown you tonight is optional,” he says.
“Both in banking and nature,” Earnhardt says, “when we make too many withdrawals and not enough deposits… there’s a deficit.” There are too many creatures we have already lost. The eastern cougar. The Carolina parakeet. The passenger pigeon. Too many more. There are still others that are threatened or endangered but not yet gone. “We humans tend to forget the failures and close calls,” Earnhardt says. While talking about biodiversity loss, he references a quote by biologist E.O. Wilson: “This is the folly our descendants are least likely to forgive us.”
A swallow-tailed kite. Earnhardt says that these kites, which spend their winters in South America, now nest along several rivers in southeastern North Carolina.
So what can be done? To preserve biodiversity, we have to consider entire ecosystems, not just one endangered animal at a time. “We are part of the natural world, part of links and chains and pyramids,” Earnhardt says, and humans too often forget that. Everything is connected.
He recalls visiting entomologist Bill Reynolds’s lab and noticing crickets hopping across the floor. “Don’t step on the transmission fluid!” Reynolds warned. He was referring to the crickets and to insects more broadly. Like transmission fluid in cars, insects are essential to making sure the systems they are part of run smoothly. Insects serve crucial roles in food webs, pollination, and decomposition. Studies show that they are declining at alarming rates.
“We are at a crossroads,” Earnhardt says. “Our transmission fluid is low, and we have made too many withdrawals from the bank of biodiversity.” Still, he emphasizes the importance of not giving up on wildlife conservation. Given a chance, nature can and will regenerate.
Tupelo tree buttresses on Tar River near Greenville, North Carolina.
Despite all our past and current failures, conservation also has remarkable success stories. The brown pelican is one North Carolina resident that almost went extinct but has since “come back in incredible numbers.” The bald eagle is another. Its population plummeted in the 20th century, largely due to the insecticide DDT as well as habitat loss and hunting. By 2007, though, after intensive conservation efforts, it had rebounded enough to be removed from the endangered species list. Until about 1980, Earnhardt had never seen a bald eagle in North Carolina. Today, Earnhardt says, “I see them in every county.”
A bald eagle that Earnhardt saw near the Raleigh-Durham airport. Bald eagles, once on the brink of extinction, can now be seen in every county in North Carolina.
“Everyone’s going to have to fly in the same direction,” to preserve North Carolina — not to mention the rest of the world — at its best and wildest, Earnhardt says. But individual actions can make a difference. He suggests planting native flowers like milkweed and coneflower, both of which are good food sources for pollinators. And if you choose to plant ornamentals like crepe myrtle, “Treat that as a piece of art in the yard and then plant the rest as native.”
Lady Bird Johnson, a former first lady and conservation advocate, once said that “Texas should look like Texas, and Mississippi like Mississippi.” Choosing native plants can be a powerful way to help native wildlife in your own yard. “If you plant it,” Earnhardt says, “they will come.”
One audience member asks, “How do you recommend that we recruit non-believers?” It’s a conundrum that Earnhardt has put a lot of thought into. “It takes time, and it takes patience,” he says. “Some of my best friends are not full believers, but I work on them every day.”
Statistics and computer science double major Jenny Huang (T’23) started Duke as many of us do – vaguely pre-med, undecided on a major – but she knew she had an interest in scientific research. Four years later, with a Quad Fellowship and an acceptance to MIT for her doctoral studies, she reflects on how research shaped her time at Duke, and how she hopes to impact research.
Jenny Huang (T’23)
What is it about statistics? And what is it about research?
With experience in biology research during high school and during her first year at Duke, Huang toyed with the idea of an MD/PhD, but ultimately realized that she might be better off dropping the MD. “I enjoy figuring out how the world works” Huang says, and statistics provided a language to examine the probabilistic and often unintuitive nature of the world around us.
In another life, Huang remarked, she might have been a physics and philosophy double major, because physics offers the most fundamental understanding of how the world works, and philosophy is similar to scientific research: in both, “you pursue the truth through cyclic questioning and logic.” She’s also drawn to engineering, because it’s the process of dissecting things until you can “build them back up from first principles.”
At the International Society for Bayesian Analysis summer conference in Montreal
Huang’s research and the impact of COVID-19
For Huang, research started her first year at Duke, on a Data+ team, led by Professor Charles Nunn, studying the variation of parasite richness across primate species. To map out what types of parasites interacted with what type of monkeys, the team relied on predictors such as body mass, diet, and social activity, but in the process, they came up against an interesting phenomenon.
It appeared that the more studied a primate was, the more interactions it would have with parasites, simply because of the amount of information available on the primate. Due to geographic and experimental constraints, however, a large portion of the primate-parasite network remained understudied. This example of a concept in statistics known as sampling bias was muddling their results. One day, while making an offhand remark about the problem to one of her professors (Professor David Dunson), Huang ended up arranging a serendipitous research match. It turned out that Dunson had a statistical model that could be applied to the problem Nunn and the Data+ team were facing.
The applicability of statistics to a variety of different fields enamored Huang. When COVID-19 hit, it impacted all of us to some degree, but for Huang, it provided the perfect opportunity to apply mathematical models to a rapidly-changing pandemic. For the past two summers, through work with Dunson on a DOMath project, as well as Professor Jason Xu and Professor Rick Durrett, Huang has used mathematical modeling to assess changes in the spread of COVID-19.
On inclusivity in research
As of 2018, just 28% of graduates in mathematics and statistics at the doctoral level identified as women. Huang will eventually be included in this percentage, seeing as she begins her Ph.D. at MIT’s Department of Electrical Engineering and Computer Science in the fall, working with Professor Tamara Broderick.
“When I was younger, I always thought that successful and smart people in academia were white men,” Huang laughed. But that’s not true, she emphasizes: “it’s just that we don’t have other people in the story.” As one of the few female-presenting people in her research meetings, Huang has often felt pressure to underplay her more, “girly” traits to fit in. But interacting with intelligent, accomplished female-identifying academics in the field (including collaborations with Professor Cynthia Rudin) reaffirms to her that it’s important to be yourself: “there’s a place for everyone in research.”
At the Joint Statistical Meetings Conference in D.C with fellow researcher Gaurav Parikh
Advice for first-years and what the future holds
While she can’t predict where exactly she’ll end up, Huang is interested in taking a proactive role in shaping the impacts of artificial intelligence and machine learning on society. And as the divide between academia and industry is becoming more and more gray, years from now, she sees herself existing somewhere in that space.
Her advice for incoming Duke students and aspiring researchers is threefold. First, Huang emphasizes the importance of mentorship. Having kind and validating mentors throughout her time at Duke made difficult problems in statistics so much more approachable for her, and in research, “we need more of that type of person!”
Second, she says that “when I first approached studying math, my impatience often got in the way of learning.” Slowing down with the material and allowing herself the time to learn things thoroughly helped her improve her academic abilities.
Being around people who have this shared love and a deep commitment for their work is just the human endeavor at its best.
Jenny huang
Lastly, she stresses the importance of collaboration. Sometimes, Huang remarked,“research can feel isolating, when really it is very community-driven.” When faced with a tough problem, there is nothing more rewarding than figuring it out together with the help of peers and professors. And she is routinely inspired by the people she does research with: “being around people who have this shared love and a deep commitment for their work is just the human endeavor at its best.”
Post by Meghna Datta, Class of 2023
(Editor’s note: This is Jenny’s second appearance on the blog. As a senior at NC School of Science and Math, she wrote a post about biochemist Meta Kuehn.)
Geer Cemetary in Durham is one of many burial grounds in America that hold the remains of thousands of Black Americans from the 19th century. There are no records of the people buried there. The process of researching grounds like these as a form of reparations to descendent communities was pioneered by Michael Blakey in the African Burial Ground Project in Lower Manhattan, New York. He is currently the Director of the Institute for Historical Biology at the College of William and Mary.
On April 4, Blakey visited Duke as a guest of the Franklin Institute of Humanities, the Department of Classical Studies, the Department of International Comparative Studies, and Trinity College. In attendance to his lecture were students of Classical Studies 144: Principles of Archaeology with Alicia Jimenez, International Comparative Studies 283: Death, Burial, and Justice in the Americas with Adam Rosenblatt, and several graduate students by invitation (and me). His presence was clearly highly anticipated.
I initially approached Dr. Jimenez with my interest in bioarchaeology in January as I was planning my Program II application. She invited me to this seminar, and to lunch with Blakey and the graduate students beforehand. I came prepped with questions on osteopenia and hypertrophy, as well as a map of Brightleaf Square so I wouldn’t get lost (I still got lost) and a few dollars cash for parking (they only took card).
For those of you who have ever loved the detective fiction heroine Temperance Brennan, Blakey’s work is for you. He is co-chair of the Commission for the Ethical Treatment of Human Remains through the American Anthropological Association. He was claiming the title of bioanthropologist before it was cool. He wrote a guide for the profession called Engaging Descendant Communities, or, more lovingly, The Rubric. Blakey encourages allowing those descendant communities to guide scientists’ research on human remains. He calls us Homo reminiscens, because what makes us “human” may be our affinity for memorializing our dead as much as it may be our large brains (á la Homo sapiens). “Burial is human dignity,” Blakey announced during the seminar, “Dignity is what we do.”
“Ethical code is not law. It is our greatest responsibility.”
Michael Blakey
After all, science has historically been used to justify the unjust. Bioarchaeology is a famous contributor to the field; the pseudoscience of phrenology was upheld until well into the 20th century, and was originally used as “scientific proof” that people of African descent were lesser than Europeans. It was also cited as a justification for displacing Native Americans from their lands.
During lunch, I was struck by Blakey’s cadence. He had a deep, slow voice and spoke with intention. He ordered the giant pretzel. I never asked my questions; instead, I was swept away by the group’s discussion on ethics–a topic I had no open Safari tabs on. I asked instead why a scientist would choose to guide themselves entirely by a non-expert opinion rather than scientific inquiry; would that not hinder discovery?
The scientific method, as you may recall, starts with asking a question. Rather than gracefully including descendent communities after the paper has been written, Blakey urges scientists to only pursue questions about remains that the descendants wish to answer. The science of death should never be self-serving, he noted. There is no purpose to publishing a paper if it is not in the service of the community that provided the subject. A critical reader may notice that The Rubric is not called The Gospel or The Constitution. Rather than a rule of law, it is a guideline. That’s because ethics is based on the respect of self, of craft, and of others. “Ethical code is not law,” Blakey reminds scientists. “It is our greatest responsibility.”
Geer Cemetary has been the subject of Duke research for years now, from a Story+ program to class field trips. Members of ICS, CLST, and FHHI have been in cooperation with Friends of Geer Cemetary to answer such questions about burial conditions–the attempt at dignity granted to Black residents of Durham by their descendants.
Edit: a previous version of this article had incorrectly stated that the Department of African and African American Studies sponsored Michael Blakey’s lecture.
According to a recent NPR/Ipsos poll, nearly 70% of Americans believe that U.S. democracy is “in crisis and at risk of failing.” Two out of every three respondents also agree that U.S. democracy is “more at risk” now than it was a year ago.
These fears are not unfounded. For the past three years, the United Nations Human Development Report has issued increasingly grave warnings for the state of the world. The warnings focus specifically on the Anthropocene, rising inequality, and growing polarization, conveying themes of both uncertainty and hope.
Pictured above: The 2022 Human Development Report.
“People should be able to live their lives at their full potential,” Dr. Conceição began. “When you look at the world and see how people are living their lives compared to how they should be living their lives, you get the need for human development.”
First introduced in 1990, the Human Development Report focuses on improving the quality of human life, rather than just the economy in which human beings live. The report emphasizes three pillars: people, opportunity, and choice. “Living life to your full potential is essentially about human freedom,” Dr. Conceição said. It is these freedoms that are at risk as the conditions in the Human Development Report worsen.
Credit: 2021/22 United Nations Human Development Report.
“We need to dig more deeply into why we aren’t taking action,” Conceição maintains. He explains that current efforts to spark change are too factual. Governments and corporations are focused too heavily on raising awareness and should pivot to trying to take tangible steps.
Political division is also a major source of stagnation, as those who lie on either side of the spectrum tend to be more insecure in their views of the future. Because of these obstacles, it requires a “more complex and unusual way of trying to understand these problems.”
The report has citizens from around the world concerned about potential declines in the quality of well-being. But Dr. Conceição asserts that the reports are meant to communicate hope.
“It’s precisely because we are having this level of uncertainty that this becomes even more relevant,” he said. In fact, it is this uncertainty that the report will build off of for future publications. The literature will dig deeper into novel areas of uncertainty, to figure out the best way forward.
An analysis of the current global uncertainties. Credit: 2021/22 United Nations Human Development Report.
Dr. Conceição urges students to invest in the United Nations and its initiatives, as it is crucial in creating a better outlook on the future. As Abraham Lincoln once expressed, “The most reliable way to predict the future is to create it.”
Want to get involved with the United Nations? Click here!
I recently had the pleasure of attending Professor Janet Malek’s lecture: Only Mostly Dead? The Evolving Ethical Evaluation of Death by Neurologic Criteria, a lecture sponsored by the Trent Center for Bioethics, Humanities & History of Medicine.
Dr. Malek is an associate professor in the Duke Initiative for Science & Society, and at the Baylor College of Medicine Center for Medical Ethics and Health Policy.
Janet Malek Ph.D.
We don’t often talk about death. On the surface, it seems like it would be a straight-forward concept. You’re either dead, or you’re not dead. Right? It turns out that clinically defining death is not so simple.
Popular media has some grasp on the ambiguity of the definition of death. Remember this scene from the popular movie, The Princess Bride? Suspecting that the protagonist is dead, his friends bring him to a miracle-worker and have the following conversation.
Miracle Max: “Whoo-hoo-hoo, look who knows so much. It just so happens that your friend here is only MOSTLY dead. There’s a big difference between mostly dead and all dead. Mostly dead is slightly alive. With all dead, well, with all dead there’s usually only one thing you can do.
Inigo Montoya: What’s that?
Miracle Max: Go through his clothes and look for loose change.
In real life, death used to be determined by cardiopulmonary criteria – when the heart and lungs stop working. In recent decades the idea that death can be determined using neurologic criteria – when the brain stops working – has gained acceptance. As neuroscience and technology has evolved, so too have our definitions. Now that we know more about how the brain works, we know that there may be some brain activity even after a person has met the criteria for death by neurologic criteria (DNC). This leads to philosophically rich and practically relevant questions of ethics – for example, when do we stop providing life-sustaining care? In the field of bioethics and beyond, there is high demand for discussion on this topic.
There has been controversy over defining death since the 1650’s — when a woman named Anne Greene woke up after being hanged. It wasn’t until the 1980’s that a consensus definition of death was first identified. Here is a brief history:
1950s
Widespread availability of ventilators led to the identification of a state described as death of the neurological system.
1960s
Advances in organ transplantation foster discussion on the ethics of defining death.
A committee at Harvard Medical School examined the definition of Brain Death. They created a definition of “Irreversible Coma,” which focused on loss of neurological function.
1980s
The 1980 Uniform Determination of Death Act (UDDA) provided a legal basis for clinically determining death as: an individual who has sustained either 1) irreversible cessation of circulatory and respiratory functions OR 2) irreversible cessation of functions of the entire brain.
1981: President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research report. Findings are centered on questions of functioning of the organism as a whole and the brain’s role in coordinating it.
1990s-2000s
Clinicians arrive at general agreement that a patient in a state of coma or unresponsiveness, without brainstem reflexes and who fails an apnea test is dead by neurologic criteria. Largely it is accepted that “brain death is death” but there is not complete consensus.
2010-late
2013: Case of Jahi McMath. A 13-year old girl was declared “brain dead” in California, and a death certificate was issued. However, the family fought to have her maintained on life support. They moved to New Jersey, the only state which recognized objections to brain death, and the “brain dead” declaration was reversed. Jahi lived there for 4 years before passing away. This famous case caused people to reconsider the concept of brain death.
2020s:
Recent innovations in heart transplantation technology will likely challenge the acceptance of the Dead Donor Rule (DDR) which requires that an individual is clinically declared dead before vital organs are removed for transplantation.
2021: Assembly of the Determination of Death Committee, tasked with updating the Uniform Determination of Death Act (UDDA). Duke faculty (and founding director of Science & Society) Nita Farahany, is involved with this process.
What ethical issues and practical questions challenging Death by Neurologic Criteria (DNC) today? Dr. Malek shared the following case.
Following a tragic car accident, Ms. Jones, a 20-year-old college student, was brought to the hospital, having suffered significant anoxic brain injury. The medical team determined that she met criteria for DNC. However, her family refused to allow for further testing. Several days passed. Ms. Jones was maintained on life support, during which she did not show signs of improvement. After several difficult conversations, the family consented for assessment and Ms. Jones was declared dead — using the criteria associated with DNC.
What is the proper amount of time to continue life-sustaining treatment if a physician suspects the patient will never recover?
Although this may sound like an uncommon occurrence, nearly half of neurologists have been asked to continue neurologic support for patients that may meet criteria for DNC.
Obligating life support for patients suspected of meeting DNC, either through the family’s refusal for testing or by direct request, would likely result in ethical harms such as violation of the dignity of decedent, unjustly using scarce resources, or causing moral distress in caregivers.
However, it may be permissible to maintain life support in these situations. Dr. Malek says that we do not yet have a good ethical framework for this. Reasonable accommodations that are in line with professional guidelines probably have minimal impact, and might provide some psychosocial benefits to families.
Is consent required to test for DNC? Should it be?
These are extremely difficult questions, and there is continuing controversy over what the correct answers should be. Dr. Malek advises medical experts to work with healthcare administrators to develop clear institutional policies.
Post by Victoria Wilson, 2023 MA student in Bioethics & Science Policy
Black-capped chickadees have an incredible ability to remember where they’ve cached food in their environments. They are also small, fast, and able to fly.
So how exactly can a neuroscientist interested in their memories conduct studies on their brains? Dmitriy Aronov, Ph.D., a neuroscientist at the Zuckerman Mind Brain Behavior Institute at Columbia University, visited Duke recently to talk about chickadee memory and the practicalities of studying wild birds in a lab.
Black-capped chickadees, like many other bird species, often store food in hiding places like tree crevices. This behavior is called caching, and the ability to hide food in dozens of places and then relocate it later represents an impressive feat of memory. “The bird doesn’t get to experience this event happening over and over again,” Aronov says. It must instantly form a memory while caching the food, a process that relies on episodic memory. Episodic memory involves recalling specific experiences from the past, and black-capped chickadees are “champions of episodic memory.”
They have to remember not just the location of cached food but also other features of each hiding place, and they often have only moments to memorize all that information before moving on. According to Aronov, individual birds are known to cache up to 5,000 food items per day! But how do they do it?
Chickadees, like humans, rely on the brain’s hippocampus to form episodic memories, and the hippocampus is considerably bigger in food-caching birds than in birds of similar size that aren’t known to cache food. Aronov and his team wanted to investigate how neural activity represents the formation and retrieval of episodic memories in black-capped chickadees.
Step one: find a creative way to study food-caching in a laboratory setting. Marissa Applegate, a graduate student in Aronov’s lab, helped design a caching arena “optimized for chickadee ergonomics,” Aronov says. The arenas included crevices covered by opaque flaps that the chickadees could open with their toes or beaks and cache food in. The chickadees didn’t need any special training to cache food in the arena, Aronov says. They naturally explore crevices and cache surplus food inside.
Once a flap closed over a piece of cached food (sunflower seeds), the bird could no longer see inside—but the floor of each crevice was transparent, and a camera aimed at the arena from below allowed scientists to see exactly where birds were caching seeds. Meanwhile, a microdrive attached to the birds’ tiny heads and connected to a cable enabled live monitoring of their brain activity, down to the scale of individual neurons.
An artistic rendering of one of the cache sites in an arena. “Arenas in my lab have between 64 and 128 of these sites,” Aronov says. Drawing by Julia Kuhl.
Through a series of experiments, Aronov and his team discovered that “the act of caching has a profound effect on hippocampal activity,” with some neurons becoming more active during caching and others being suppressed. About 35% percent of neurons that are active during caching are consistently either enhanced or suppressed during caching—regardless of which site a bird is visiting. But the remaining 65% of variance is site-specific: “every cache is represented by a unique pattern of this excess activity in the hippocampus,” a pattern that holds true even when two sites are just five centimeters apart—close enough for a bird to reach from one to another.
Chickadees could hide food in any of the sites for retrieval at a future time. The delay period between the caching phase (when chickadees could store surplus food in the cache sites) and the retrieval phase (when chickadees were placed back in the arena and allowed to retrieve food they had cached earlier) ranged from a few minutes to an hour. When a bird returned to a cache to retrieve food, the same barcode-like pattern of neural activity reappeared in its brain. That pattern “represents a particular experience in a bird’s life” that is then “reactivated” at a later time.
Aronov said that in addition to caching and retrieving food, birds often “check” caching sites, both before and after storing food in them. Of course, as soon as a bird opens one of the flaps, it can see whether or not there’s food inside. Therefore, measuring a bird’s brain activity after it has lifted a flap makes it impossible to tell whether any changes in brain activity when it checks a site are due to memory or just vision. So the researchers looked specifically at neural activity when the bird first touched a flap—before it had time to open it and see what was inside. That brain activity, as it turns out, starts changing hundreds of milliseconds before the bird can actually see the food, a finding that provides strong evidence for memory.
What about when the chickadees checked empty caches? Were they making a memory error, or were they intentionally checking an empty site—even knowing it was empty—for their own mysterious reasons? On a trial-by-trial basis, it’s impossible to know, but “statistically, we have to invoke memory in order to explain their behavior,” he said.
A single moment of caching, Aronov says, is enough to create a new, lasting, and site-specific pattern. The implications of that are amazing. Chickadees can store thousands of moments across thousands of locations and then retrieve those memories at will whenever they need extra food.
It’s still unclear how the retrieval process works. From Aronov’s study, we know that chickadees can reactivate site-specific brain activity patterns when they see one of their caches (even when they haven’t yet seen what’s inside). But let’s say a chickadee has stored a seed in the bark of a particular tree. Does it need to see that tree in order to remember its cache site there? Or can it be going about its business on the other side of the forest, suddenly decide that it’s hungry for a seed, and then visualize the location of its nearest cache without actually being there? Scientists aren’t sure.
