Barn swallows may indeed have evolved alongside barns, humans

As humans evolved and expanded, so too did barn swallows, new research from CU Boulder suggests

The evolution of barn swallows, a bird ubiquitous to bridges and sheds around the world, might be even more closely tied to humans than previously thought, according to new study from the University of Colorado Boulder.

The research, published this week in Molecular Ecology, offers preliminary insight suggesting that the barn swallow and its subspecies evolved alongside—but independently from—humans. These new results make it one of the only known species, in addition to microscopic organisms like bacteria or viruses, to have developed in such a way, upending previous assumptions that barn swallows evolved prior to human settlement.

“Humans could be a really big part of the story,” said Rebecca Safran, a co-author of the study and an ecology and evolutionary biology (EBIO) associate professor at CU Boulder. “There’s very few studies that can point to the exact influence of humans, and so here, this coincidence of human expansion and permanent settlement and the expansion of a group that relies really, really heavily on humans is compelling.”

Barn swallows are found across the northern hemisphere and are characterized by their mud-cup nests that are built nearly exclusively on human-made structures. Despite their prevalence, however, not much is known about their evolutionary history, the timing of their expansion from northern Africa (where they originated) or how the six subspecies evolved so physically and behaviorally different yet remain almost genetically identical.

Previous studies published in the Proceedings of the Royal Society of London and Molecular Phylogenetics and Evolution looked into these questions and found that the different subspecies split early, well before human settlement.

Humans could be a really big part of the story. … There’s very few studies that can point to the exact influence of humans, and so here, this coincidence of human expansion and permanent settlement and the expansion of a group that relies really, really heavily on humans is compelling.

Rebecca Safran, ecology and evolutionary biology associate professor

This new study, however, gave the topic a fresh look by examining the whole genome of 168 barn swallows from the two sub-species farthest apart on an evolutionary scale: H. r. savignii in Egypt (a non-migratory species that lives along the Nile) and H. r. erythrogaster in North America (a species found throughout North America that migrates seasonally to South America).

These data—which are on the order of 100,000 times bigger than the previous dataset used—were then analyzed with more sophisticated computational resources and methods than previously available. This allowed researchers to get a more complete picture that places the timing of barn swallow differentiation or speciation (i.e., when the barn swallow subspecies separated) closer to that of when humans began to build structures and settlements.

“The previous studies were playing with the idea of potential impact on population sizes due to humans,” said Chris Smith, a graduate student in EBIO and the Interdisciplinary Quantitative Biology program, and the study’s lead author. “Our results suggest a much more substantial link with humans.”

These new preliminary findings also suggest that this evolutionary link may have been forged through a “founder event,” which is when a small number of individuals in a species take over a new environment and are able to expand their new population there thanks to an availability of resources and an absence of competitors. For barn swallows, this event may have occurred rapidly when they moved into a new, relatively empty environment: alongside humans.

“Everyone is always wondering how do you study speciation? It’s been viewed as this long-term, million-year (process), but in barn swallows, we are not talking about differentiation within several thousands of years,” said Safran. “Things are really unfolding rather rapidly.”

Smith concurred: “It’s interesting to study speciation in the beginning steps.”

Republished with permission from the Colorado Arts and Sciences Magazine, where it was published in 2018.

Diversity begets diversity in the alpine

As plant communities become more diverse and complex in the high alpine, so to do soil microorganisms, according to a new CU Boulder study

Increases in plant diversity and complexity above ground leads to a greater soil biodiversity below ground, according to new research from the University of Colorado Boulder.

This study, which is out today in Ecology, looked to the high alpine environment of the Rocky Mountains, where plants are increasingly colonizing new territory due to climate change, and found that as plants move into these new environments, the soil diversity seems to move with them, documenting for the first time in the field this plant-soil diversity relationship.

“We are really excited that this system, being so simple, actually does show this connection,” said Dorota Porazinska, the lead author of the study and a research associate in the Department of Ecology and Evolutionary Biology at CU Boulder. “If there was a place where we would expect to see a relationship between the diversity of plants and microbes, that would be in this system. It’s a nice delivery that, yes, indeed, it’s present.”

It is well established that ecosystems, including plants and soil microbes depend on each other in much the same way as humans rely on their own internal microbiome for health and well-being. What is less known, however, is how the diversity of one affects the diversity of the other. While experimental results have suggested that there is indeed a connection, nothing solid had thus far been observed in nature.

This research, however, found otherwise by looking at an environmental blank slate: the high alpine of Colorado.

Diversity begetting diversity is something that hasn’t really been proven. … And these results really show that it is happening and that the relationship exists in nature, and not just in some laboratory experiments.

Steven Schmidt, Department of Ecology and Evolutionary Biology PROFESSOR

As the climate changes, high alpine environments in Colorado—those zones between 12,000 and 14,000 feet above sea level—have been experiencing significant environmental shifts. Where there were once only barren soils, there are now new mosses, lichens and plant communities fostered by a longer growing season.

For the study, the researchers collected a variety of plant and soil samples along a natural environmental gradient from such an environment in the Front Range of the Rocky Mountains. They then analyzed the soil microbiota (the organisms living within the soil), the carbon and nitrogen in the soil (required nutrients for plant growth) and the soil moisture to see if there were any relationship between the plants, soil diversity and the broader soil environment.

They found that, at least in this high alpine environment, there is a strong connection between plants moving in and the soil undergoing complex changes in response.

“Diversity begetting diversity is something that hasn’t really been proven,” said Steven Schmidt, a co-author and a professor in the Department of Ecology and Evolutionary Biology. “And these results really show that it is happening and that the relationship exists in nature, and not just in some laboratory experiments.”

Republished with permission from the Colorado Arts and Sciences Magazine, where it was published in 2018.

To confront wildfire risk, experts get social

The WiRē team—a group of wildfire practitioners and researchers, including some from the University of Colorado Boulder—is working across Colorado to better understand the human role in local wildfire mitigation

For the community of Mountain Village in southwestern Colorado, it was all about the trees.

Anything that involved cutting down trees was a non-starter for this picturesque community near Telluride, according to the town council’s understanding at the time. Residents just weren’t willing to get rid of them, they argued, even to reduce wildfire risk. A group of researchers and wildfire practitioners—or the Wildfire Research (WiRē) team—however, saw this challenge as an opportunity to do things a little bit different.

The team—which includes sociologists, economists and wildfire mitigation specialists (or wildfire practitioners) with ties both to the University of Colorado Boulder and federal agencies throughout Colorado—surveyed local residents and quickly disproved the conventional wisdom. In fact, 77 percent of Mountain Village respondents reported being willing to remove their trees to reduce wildfire risk and help protect their homes.

With data in hand, a member of the WiRē team and the director of a regional wildfire organization, Lilia Falk (Geog’10) of the West Region Wildfire Council, went to the town council and showed them that not only were a majority of respondents willing to remove trees to reduce wildfire risk, but that they felt there were both perceived barriers and distinct motivations for completing this work.

Mountain Village, much like other mountain communities throughout Colorado, was struggling to reconcile two apparently competing goals: making itself safer from wildfire while also preserving the beauty that draws many of its residents. And it is this tension, that while wildfire is a natural phenomenon, learning to live with wildfire is social—and social solutions are also needed to save lives and property—that the WiRē team hopes to address.

“As a nation, we’re spending a lot of time, money and resources suppressing fires—especially fires that threaten homes and communities. But the human condition is such that humans choose to build in those areas. Humans choose. So, just the concept that, yes, it is a hazardous fuels issue, yes, it is a structure issue, but its first and foremost a social issue that needs to be addressed,” said Falk.

Yes, it is a hazardous fuels issue. Yes, it is a structure issue. But its first and foremost a social issue that needs to be addressed.

Lilia Falk

Learning how to not only prepare for wildfires, but also live alongside them, is a difficult task, and one that the WiRē team hopes to help residents living in the wildland-urban interface—the transitional area between vegetation and homes—overcome through a combination of social science research and on-the-ground work, all to create more wildfire adapted communities.

They accomplish this through the systematic collection of household data via surveys. The team then pairs those data with parcel-by-parcel wildfire risk assessments, which are completed by professional wildfire mitigation specialists. From there, the team’s researchers analyze the findings and generate reports about the community and their relationship to wildfire, including residents’ risk perception, wildfire experience and their opinions of wildfire and mitigation work.

These reports, and the data within them, are then used by the team to craft useful products for the practitioners, including presentations, infographics and story synopses to help facilitate community conversations, and help expand the social science literature around wildfire adaptation and mitigation.

The collaboration, though, doesn’t end there. The researchers and practitioners use this as a jumping off point, continuing to work together to figure out how they can fine tune their research questions and create new programs aimed at improving wildfire preparedness.

Thus far, the team has collected data from roughly 80 communities across Colorado and has garnered about 6,000 risk assessment observations, predominantly in southwest and southcentral Colorado, with no plans of stopping.

One way they’re expanding their work is by creating the WiRē Center—a non-profit outgrowth of the team. The center looks to help garner resources to further the goals of the group and to support more research-practitioner partnerships across Colorado and beyond.

This multi-faceted approach is especially important as wildfires grow in size and intensity, and more people move into the wildland-urban interface.

Wildfires are usually approached in the United States with a focus on mitigation (attempting to reduce the damage or risk of wildfires), and suppression (putting a fire out when it does occur). Homeowners and landowners are often encouraged to take care of their own property to reduce wildfire risk, but often they lack the specific information concerning how to do it, or to what extent they need to take action.

And often, according to Hannah Brenkert-Smith (PhD, Soc’08) of the WiRē team, wildfire management policies try to be a one-size-fits-all approach, which doesn’t necessarily work.

“A common limitation we see is not that homeowners don’t know their homes are at risk of wildfire—they’re often quite aware of that in a general sense—but where some of the information disconnect comes in is that people don’t necessarily know the specifics,” said James Meldrum (PhD, EnvSt’12), a research economist with the U.S. Geological Survey who is a member of the WiRē team, and, formerly, a research associate with the CU Boulder’s Institute of Behavioral Science. “They might be taking action such as creating defensible space around their home, but they might not be doing it to the level that the practitioner would want them to be doing, or that would be as effective as it could be.”

“We’re seeing that providing that information really makes a difference.”

Beyond just a lack of information, another barrier to mitigation efforts is the sheer initial cost of the endeavor. Research shows, however, that for every dollar invested in mitigation before a big wildfire disaster, society saves $4 in suppression costs when the wildfire burns.

We believe that if more investment happens in the upfront side of things, supporting community risk reduction, that we can reduce impacts in local communities from major wildfires,” said Brenkert-Smith, an environmental sociologist and research faculty with the Environment and Society program at the Institute of Behavioral Science. “But at this point in time, the machine to respond to fires is so big and so hungry that there are few dollars left to put on this front-end piece.”

Hannah Brenkert-Smith is an environmental sociologist and research faculty with the Environment and Society program at the Institute of Behavioral Science.

“And so, what we’re trying to do is create a way—a systematic way—of investing dollars so that when wildfire programs and practices are underway, that they’re efficient, they’re tracking what works, and they’re responding to the local context.”

One way that the WiRē team is attempting to create this systematic approach differently is by incorporating wildfire practitioners into their work and research from the very beginning of the process.

The practitioners work directly with homeowners to make sure that they’re informed, their homes are safe, and that any potential destruction on their homes or property is mitigated. These mitigation efforts include creating defensible space (or the buffer between a home and the forest around it), hardening a home (adding building materials that are more fire resistant), and introducing fire-resistant landscaping. But, they can also include outreach and working with the community directly.

Historically, practitioners have worked in their own silos, separate from the research conducted on mitigation and suppression. What the WiRē team provides is a different, data-driven, people-driven approach that improves efficiency.

And the partnership between the researchers and practitioners is something that both groups appreciate.

For the West Region Wildfire Council, a nonprofit group that works with the WiRē team in Gunnison, Hinsdale, Delta, Montrose, Ouray and San Miguel counties, that has definitely been the case.

“Having that information provided by the WiRē approach has absolutely been critical to the evolution and efficacy of our programs,” said Falk, who is also a member of the WiRē team. “We’ve been able to infuse that information into our programs, think critically, modify and change over time.”

That appreciation holds true for the researchers as well: “It’s really been pretty inspiring working with the practitioners so closely,” said Meldrum. “It’s been a pretty incredible opportunity to be able to work with such forward thinking and innovative people who very much care about the problem. Everyone really does give 110 percent.”

This innovative approach, and how well it has worked, has spurred the group to get the message out for other potential researcher-practitioner partnerships, and one way they are doing that is through newly released outreach videos on their website. The videos each emphasize a different aspect of the WiRē team and WiRē Center’s collaborative approach to the social side of wildfire.

The first video, “An Innovative Approach to Understanding Communities,” introduces the WiRē team, and provides an overview of how they’re helping communities adapt.

“Something that we really tried to emphasize in these videos is the process of understanding a community in detail and working to see how to use that understanding to improve the engagement of the community in becoming more fire adapted,” said Meldrum.

“We hope these videos can convey that message and encourage other places to take this approach.”

Brenkert-Smith agrees, “Our intent really was to tell people our story about how research and practice don’t have to live in separate worlds, and how we’ve managed to join together in a collaborative effort that really challenges the way things usually get done.”

“And part of this is try to say, ‘We have something. It’s real. It’s working.'”

The WiRē Center and team are looking to expand beyond just their current areas to Grand County, Colo., and central Washington.

“We directly have data on 80 communities right now, and that’s growing,” commented Brenkert-Smith.

“It’s really exciting because the practitioners that we’ve been working with, and even those we’ve just had conversations with, lament that sometimes they steer their programs to respond to the vocal community members who have really strong opinions about how things should be done or shouldn’t be done. But, what we’ve learned is that sometimes those voices don’t actually represent the majority of the people in their communities.”

“So, there’s a feeling that things can change because of this process.”

Republished with permission from the Colorado Arts and Sciences Magazine, where it was published in 2018.

Smoke from distant fires darken the public health picture

Questions remain about the respiratory risk posed to a fifth of the United States population by increasing wildfires—but a CU Boulder researcher is trying to clear the air

It had already been an exceptional fire season across the American West by the time Montana’s Rice Ridge fire ignited.

It began in July 2017 as many western wildfires do: with a dry lightning strike on a parched patch of plant litter. Immediately it stirred an inferno that stretched for miles and, by September, consumed an area of forest almost twice the size of Denver, producing enough thick smoke to choke half of the country.

“It’s been described to me in apocalyptic terms,” Sarah Coefield, an air quality specialist with the Missoula City-County Health Department, told the Washington Post at the time about the area surrounding the fire.

The orange plumes of ash were so dense that Coefield commented in that same interview that, “Visibility has been down to less than a block.”

Miles away from Montana, that same thick, orange haze, accompanied by the ash of other wildfires in California, Oregon and Washington, heaved its way across the rolling hills of the Midwestern tallgrass prairies—and they weren’t alone in their suffocation.

Before all was said and done, this smoke—accumulated from dozens of wildfires—had hijacked the meandering jet stream, getting a first-class ticket to blanket more than 3,000 miles of middle America. It ultimately traveled as far east as New York and Pennsylvania and as far south as Texas, and illustrated yet another example of a new normal for those in and out of the Smoke Belt.

At the smoke's peak, its plume spread over 3,000 miles across the United States. Photo courtesy of NASA.
At the smoke’s peak, its plume spread over 3,000 miles across the United States. Photo courtesy of NASA.

Wildfire smoke—like wildfire itself—is becoming more common and more powerful due to a changing climate, affecting communities from California to the Pacific Northwest, and from the Pacific Ocean east to the Great Plains. And yet, the documented public health effects of smoke remain relatively unknown, and, for what does exist in the research, inconsistent with a few important exceptions.

But a researcher at the University of Colorado Boulder seeks to change that, particularly for those distant fires that share their smoke.

“When we think about all of the things in the future that might be changing that influence wildfire risk and health impacts, there’s so many things,” said Colleen Reid, an assistant professor of geography at CU Boulder who studies the impact of wildfire smoke on public health. “You can’t keep fire at bay.”

The difficulty in discerning the health effects of smoke stems from the very nature of the plumes, and the U.S. approach to tracking it. Currently, there are air pollution monitors set up by the Environmental Protection Agency across the United States—often near metropolitan areas—with the goal of assessing whether air pollution regulations are working. These monitors, however, don’t always measure every day, meaning that if the wildfire is moving fast or the smoke is only hovering temporarily, they could miss the data from the high levels of smoke altogether.

Reid, though, approached this problem from three perspectives in order to improve understanding of the potential health impacts: She conducted a critical review of all existing literature on the public health impacts of wildfire smoke exposure, she researched the birth weight of babies whose mothers were exposed to smoke while pregnant, and then she specifically examined the 2008 California wildfires and their corresponding respiratory health effects for downwind populations.

At the time, the 2008 California wildfires were one of the largest fire events in the state’s history. Ignited by more than 6,000 lightning strikes, this fire event consisted of thousands of blazes raging across 26 counties in the northern half of the state.

As structures and trees burned, fine particulate matter—or the incredibly small, easily inhalable solid and liquid particles suspended in the air during a high pollution event—coated the state.

These particles—or what makes the “haze” of wildfires—aren’t just the remains of burned trees. They can also be the debris particles of human products like plastics, electrical wires and spray foam insulation, or anything else that may have gotten in the fire’s path. And, while just one of the many hazards that accompany wildfires and air pollution more broadly, it is in many respects the most dangerous for human health.

Particulate Matter is often measured in two forms: Particulate Matter 2.5 (PM2.5) and Particulate Matter 10 (PM10). PM2.5 are the fine inhalable particles that measure particles that are roughly 2.5 micrometers or smaller, while PM10 are roughly 10 micrometers and smaller. These particles—which are roughly the length of an E. coli bacterium and a single fog, mist or cloud water droplet, respectively—are so small that they can easily penetrate the lung’s alveolar sacs, which are partly responsible for exchanging oxygen between the lungs and the blood stream, and corrode its walls.

Particulate Matter's impact on the respiratory system is incredibly complex, but part of its danger is its potential to corrode alveolar walls and enter the bloodstream. Illustration courtesy of LadyofHats/Wikimedia Commons, Cay Leytham-Powell/University of Colorado Boulder.

In other words, they are able to bypass all of the body’s defenses, going straight into the blood.

Given this effect on the body, the World Health Organization has recommended that there be no minimum threshold where humans are safe to breathe in particulate matter from human-caused air pollution, which has been linked to 25 percent of lung cancer deaths, 8 percent of chronic obstructive pulmonary disease (COPD) deaths and 15 percent of heart disease and stroke cases.

And the effects don’t stop there. While sensitive populations—the young, the old, the sick—are much more vulnerable, even perfectly healthy people can feel the impact of high particulate matter through irritation to the lungs, eyes and skin, an increased risk of respiratory tract diseases and cardiovascular diseases, reduced lung function, the development of an irregular heartbeat, nonfatal heart attacks, and even premature death.

With wildfire smoke, there is a widespread consensus among researchers that these plumes do exacerbate respiratory diseases such as asthma and COPD and can cause an increased risk of death for sensitive populations, but in terms of the other effects, there is still a lack of agreement—particularly for those impacted downwind.

Right now, the EPA has the daily limit of all pollution related to fine particulate matter (PM2.5) set at 35 µg/m3 (micrograms per meters cubed). Ideally, with good clean air, the levels would be below 12 µg/m3. But, even at 35 µg/m3, most people (with the exception of sensitive populations) may not notice any sort of change or difficulty to their breathing.

“The fire that I studied, it (the particulate matter) maxed out close to 300 µg/m3. The Napa fires that were just happening… there were values in the 400s. So, it’s really, really bad,” said Reid. “Even San Francisco and Oakland were getting levels that were in the high 100s, low 200s, and that’s an area that tends to have pretty good air quality. So, it’s much higher than they’re used to.”

For Montana, much like California, this was the summer of smoke, with Seeley Lake—near where the Rice Ridge fire took place—experiencing record levels of smoke at 18 times what the EPA deems safe, and even breaking the air monitoring device for five hours because the pollution was simply higher than the device’s limit.

Despite this, the Front Range, and Colorado more broadly, was relatively clear and quiet. For most of the summer, the PM2.5 levels stayed within the healthy limit (normally between 0 and 20 µg/m3), well below the EPA’s limit. When Montana’s smoke begun its thick descent into the Denver metro, though, the levels spiked to between 40 and 50 µg/m3. Boulder’s jump was even more impressive, getting above 50 µg/m3 for the week of exposure.

During that time, health officials at National Jewish Health in Denver told the Denver Post that they had seen an uptick in patients reporting a shortness of breath and coughing episodes, as well as Prednisone prescriptions—all of which are common during high air pollution events, called “Action Days,” along the Front Range.

The possible health effects from those exposed during these Action Days—which are issued by the Colorado Department of Public Health & Environment for any number of air pollution issues, including any days with high particulate matter—are complicated, just like any issue related to public health.

“Severity is more related to the severity of the underlying disease than to the intensity of the exposure,” said Karin Pacheco, an allergist at National Jewish Health and an assistant professor in environmental and occupational health at the University of Colorado Denver.

We’re always going to have wildfires in the West. … So, we need to figure out how to protect health.

Colleen Reid, assistant professor of geography, CU Boulder

Similar to how healthy individuals can have differing reactions to differing levels, those among the sensitive populations—and particularly children who breathe much faster and are much more susceptible—can also have different reactions despite the original source of the pollution.

“It all is equally as horrible for the lungs,” said Lauren Massie, an undergraduate student at CU Boulder in English who suffered from severe, childhood asthma, and still suffers complications if the air pollution is too bad. “I still need to take precautions.”

Those recommended precautions to avoid the pollution, outlined by the CDC, tend to revolve around avoiding particulate matter in particular. They suggest, first and foremost, to check local air quality reports and visibility guides (which can be an indicator as to the level of particulates in the air). And, if there is anything, to stay indoors.

“Unfortunately, keeping safe on high smoke days means avoiding exposure,” commented Pacheco.

Even inside, there are a number of steps that can be taken to keep the air clear, including keeping the fresh-air intake closed, avoiding any activities that might increase indoor pollution (such as using your fireplace or burning any candles) and keeping your HVAC air filter clean.

While thus far there have been no long-term health impacts linked to smoke exposure (like what has been seen with other high-particulate matter events), the reality is that there just isn’t enough information or research yet. And, with the length of the wildfire season projected to triple, and hit closer than ever to major urban corridors due to human interference, a public health crisis of toxic air may be looming for the western United States.

Researchers, including Reid, are working on documenting these health effects for those downwind by improving the literature and watching different fire events closely, but the work is slow, expensive and extensive—and, she said, important.

“We’re always going to have wildfires in the West,” acknowledged Reid. “So, we need to figure out how to protect health.”

Republished with permission from the Colorado Arts and Sciences Magazine, where it was published in 2018.

Parasite* Snippet

Content Warnings: Forced captivity, death reference.



May 1993

When I was a child, I used to dream of a man.

Not just any man. No, he was terrifying, draped in black shadows like someone might wear clothes, the wisps ebbing and flowing across his body like they had a life of their own. And yet, even though I could never make out the features of his face, he seemed familiar. Well, except for his bright red eyes, which glowed like little flames.

Similar red eyes shined all around me from my dark prison, catching what little light existed as it filtered from cracks, snuck behind newspaper peeling from glass. The day must be ending—that was the only time that the others around me awoke, if you could even call them “awake.” Conscious would probably be closer. In this place of nightmares, each day spun in colors, sounds, sensations like a dizzying, confusing whirlpool, edges unraveling, the next fuzzier than the last.

How long had it been since I had tried to escape to the world beyond these walls? I frowned. It hadn’t worked—but I could try again. There was no reason I couldn’t.

I pushed myself from the wall and stumbled on weak legs, my knees slamming into the concrete floors. I sucked in my breath, stars blotting my vision.

Oh yeah, that was right. That was why I hadn’t tried.

I leaned forward, my hands curling in grime. I couldn’t reach the door out. My body was too fragile, too drained without Vivienne’s blood. Too close to death.


Tears welled and spilled from my eyes, droplets mixing with muck on the floor. I curled in on myself. This couldn’t be it. If I died here… Jessica… No, I needed to do something. The world beyond these walls couldn’t be one that existed only in my memories and dreams, like that man.

I had forgotten about the shadow man, who would follow me through dream-worlds, never saying a word. No, I’d catch him in the recesses of the imaginary world, waiting—always waiting. But for what, I never knew.

At some point I decided the figure was the devil.

But that only lasted until I realized that, despite what I had been told, the devil wasn’t real.

But now. Now I wasn’t so sure.

* = This is not the story’s final title

Harpy* Snippet



La Repubblica di Fiorenze, ItaliaLuglio, 1462 Anno Domini

If she can’t be their angel, then she’ll be their devil.

That’s what they decided, huddled in Piero’s room, as the plan to rescue Kilyan.

Shards of multi-colored glass fly everywhere, catching and reflecting the light as it hangs momentarily in the air in front of what remains of the stained-glass window. Francesca unfurls her limbs and lands with a definite thud on the wooden altar of her family church, glass raining around her, coating her in crystal dust.

The faces from the people sitting in the twin sides of the pews, at first shocked, transform into something worse. They scrunch, distort, their eyes widening, lips parting. Francesca smiles with her newly sharpened teeth, letting the discomfort spread. The priest, last seen a few months ago with her father, stands still like a rabbit off to the side.

After some discussion, Francesca, Piero, and Ciano agreed they couldn’t break into the prison where Kilyan was being kept—it was too big, too secure. But they could break out. It just required some theatrics to get caught.

And God, could Francesca do theatrics.

Francesca leans down and grips the edge of the altar with the tips of her fingers, black wings spread wide, blood bubbling from little cuts across across her face. She just needs to be the Francesca from the pond—capture that intoxicating absolute power, that terrifying absolute lack of power. She needs to strike fear, awe. Strands of her black hair cascade over her shoulders as she eyes the crowd. A man near the back dressed in nice, newer fabrics stands up and backs away, the soles of his shoes sliding against the floor. The first to break.

Francesca tilts her head and lifts her index finger, waving it back and forth, tsking.

* = This is not the story’s final title

Delayed Flight* Snippet


— Beth —

May 30, 2022

Sleep and I had always been enemies, but never more so than when I was stuck in the sky.

It was something about being caught in this place of forever maybes, this infinite blue prison amongst the wispy white of clouds and the silver sheen of metal, that kept me wired. And it wasn’t because it was scary—it wasn’t, at least for me; it was more annoying and a necessary evil than anything. No, it was more all of the other things that came with it: The stiff muscles, the manufactured taste of freeze-dried chicken and overly processed Italian dressing on the tongue, the anticipation of what was to come.

My back roiled in protest, and I adjusted, stretching my legs as best I could in the nest of pillows and overstuffed bags that I had created for myself, my ankles obviously swollen. My elbow knocked against mother’s on the narrow armrest. I stiffened, waiting for her inevitable scowl when her sleeping eyes opened. Her breathing remained rhythmic; her wrinkled hand twisted in the green, thread-bare blanket they gave us before takeoff. A thin relieved breath escaped my parted lips, fogging my glasses as it leaked from my face mask.

The screen in front of me flipped, switching from the safety of data to a small white plane in front of the vast expanse of Earth, a dotted line connecting the now from then, Chicago to Dublin. The dark cabin was heavy with the soft hum of an engine and the exhale of slumbering breaths. Someone a few seats away snored loudly as if to say, “See? It’s not so hard.”

I rubbed my itchy eyes. Once upon a time I had promised myself that I would never take sleeping pills, but the more I flew, the more appealing it sounded. Anything to take the edge off.

I grabbed the little travel thing of whiskey from the seat back pocket in front of me and unscrewed the top, pulling down my mask to drip the last few drops into my mouth. The burn slid down my throat, settling warm in my stomach. As if on cue, my mother’s eyes fluttered open, a snore caught in her throat. She didn’t say anything but pushed her lips together, her dark eyes, so much like my own, watching, judging. I sighed and stuck the empty plastic bottle back where I found it, moving my black cloth mask back over my mouth. Mother’s eyes closed again, and I dug out some earbuds from the front pocket of my bag.

The driving chords of a guitar reverberated in my ears. I shut my eyes and rested against the plane’s cold plastic wall, my finger tracing the petite frame, outstretched feathers of a little flying songbird tattoo on the inside of my wrist.

* = Story’s working title

Website Update

Thank you all for your interest in my work! For those just tuning in, my name is Cay Leytham and I’m a science communicator, specializing in topics related to risk and uncertainty. However, I’ve recently had two life updates that I want to update you all with.

First, I accepted a position as the Director of Communications for the Graduate School at the University of Colorado Boulder in January, 2023. That means I’m unfortunately moving away from writing about science topics for the time being and more towards strategic communications work. That said, I plan to update this website every Sunday with pieces that I’ve written over the last five years that I’m especially proud of.

Second, one topic that I haven’t delved into here is that I’m also a fiction writer, specializing in genre fiction (horror, fantasy and thriller). After some deliberation, I decided it was time to reflect that work here. I’ll also be adding snippets and updates as I have them, categorizing them as “fiction.” Eventually I plan to create a newsletter, but that is still very much a work in progress and won’t be a thing that comes about any time soon. If you are interested in receiving it once it is live, please fill out this Google form and I’ll get you on my mailing list.

Thank you for bearing with me as these changes happen! If you have any questions, definitely feel free to reach out to me at and I’ll do my best to respond.

Cannabinoids are easier on the brain than booze, study finds

Marijuana may not be as damaging to the brain as previously thought, according to new research from the University of Colorado Boulder and the CU Change Lab.

The research, which was published in the journal Addiction, examined the brains of more than 1,000 participants of varying ages, and found that long-term alcohol use is much more damaging to the brain than marijuana, contradicting years of research into the effects of marijuana and other cannabinoid products on the brain.

These findings, and other conclusions suggesting the potential public health benefits of marijuana, come amid the recent back-and-forth on federal marijuana policy and the nation’s opioid crisis.

Yet scientists are still hesitant to say that cannabinoid usage, specifically as it pertains to marijuana and its associated products, is beneficial.

“Particularly with marijuana use, there is still so much that we don’t know about how it impacts the brain,” said Rachel Thayer, a graduate student in clinical psychology at CU Boulder and the lead author of the study. “Research is still very limited in terms of whether marijuana use is harmful, or beneficial, to the brain.”

While the negative effects of alcohol on the brain have been known by researchers for years, it has been assumed that cannabinoids are as damaging to long-term brain health—if not more—given the immediate psychoactive effects of the THC (the chemical that gets a person high) in marijuana.

However, this may not necessarily be true.

With alcohol, we’ve known it’s bad for the brain for decades. But for cannabis, we know so little.

“When you look at the research much more closely, you see that a lot of it is probably not accurate,” said study co-author Kent Hutchison, a professor of behavioral neuroscience at CU Boulder and co-director of the CU Change Lab, which explores the factors linked with health and risk behavior.

“When you look at these studies going back years, you see that one study will report that marijuana use is related to a reduction in the volume of the hippocampus. The next study then comes around, and they say that marijuana use is related to changes in the cerebellum or the whatever.”

“The point is that there’s no consistency across all of these studies in terms of the actual brain structures.”

To combat this misconception in the existing literature, the researchers gave a fresh look at some existing neurological imaging data from the MRIs of both adolescents and adults to see how, using the same variables and controls, the influence of cannabinoids on the brain compared to or contrasted with alcohol. 

“With alcohol, we’ve known it’s bad for the brain for decades,” said Hutchison. “But for cannabis, we know so little.”

To see any potential difference, the researchers used the data to examine the most important neurological components: gray matter and white matter.

Gray and white matter are the two main types of tissue that make up the brain and central nervous system. Gray matter is the “stuff”—the cell bodies, dendrites and axon terminals—that enable functionality. White matter, then, is how the grey matter communicates between clusters. Any loss of size or integrity in either can make the brain not work quite like it should.

The study found that alcohol use was significantly associated with a decrease in gray matter size and white matter integrity, particularly for adults who may have decades of exposure. Marijuana and associated cannabinoid products, on the other hand, were not shown to have any long-term impact on the amount of gray matter in the brain or on the integrity of the white matter.

The research demonstrated that, “while marijuana may also have some negative consequences, it definitely is nowhere near the negative consequences of alcohol,” according to Hutchison.

Despite marijuana not being as harmful as once thought, and definitely not as damaging as other legal and illegal products, the research has not yet proved any possible benefits. This is particularly the case as it relates to the different products on the market (both THC and non-THC-containing cannabinoid products), their usage with pain and addiction treatment and the effect on different ages—especially as cannabinoid usage is on the rise among older populations.

“Considering how much is happening in the real world with the legalization movement, we still have a lot of work to do,” Hutchison said.

Republished with permission from the Colorado Arts and Sciences Magazine, where it was published in 2018.

Scholars reveal the changing nature of U.S. cities

Cities are not all the same, or at least their evolution isn’t, according to new research from the University of Colorado Boulder.

These findings, out this week in Nature Communications Earth and Environment and Earth System Science Data, buck the historical view that most cities in the United States developed in similar ways. Using a century’s worth of urban spatial data, the researchers found a long history of urban size (how big a place is) “decoupling” from urban form (the shape and structure of a city), leading to cities not all evolving the same—or even close.

The researchers hope that by providing this look at the past with this unique data set, they’ll be able to glimpse the future, including the impact of population growth on cities or how cities might develop in response to environmental factors like sea level rise or wildfire risk.

“We can learn so much more about our cities about and urban development if we know how to exploit these kinds of new data, and I think this really confirms our approach,” said Stefan Leyk, a geography professor at CU Boulder and one of the authors on the papers.

“It’s not just the volume of data that you take and throw into a washing machine. It’s really the knowing how to make use of the data, how to integrate them, how to get the right and meaningful things out there.”

Its projected that by 2050, more than two-thirds of humans will live in urban areas. What those urban areas will look like, however, is unclear, given limited knowledge of the history of urban areas, broadly speaking, prior to the 1970s.

This work and previous research, however, hopes to fill that gap by studying property-level data from the property management company, Zillow, through a property-share agreement.

This massive dataset, called the Zillow Transaction and Assessment Dataset or ZTRAX, contains about 374 million data records that include the built year of existing buildings going back over 100 years. Previously, the researchers then used these data to create the Historical Settlement Data Compilation for the United States (HISDAC-US), a set of unique time series data set that’s freely available for anyone to use.

For this new research, which were funded by the National Science Foundation, the Institute of Behavioral Sciences and Earth Lab, the researchers applied statistical methods and data mining algorithms to the data, trying to glean all available information on the nature of settlement development, particularly for metropolitan statistical areas, or high-density geographic regions.

What they found is that not only were they able to learn more about how to measure urban size, shape and structure (or form), including the number of built-up locations and their structures, they were also able to see very clear trends in the evolution of these distinct categories of urban development.

“We can learn so much more about our cities about and urban development if we know how to exploit these kinds of new data.”

Stefan Leyk, a geography professor at CU Boulder and one of the authors on the papers

In particular, the researchers found that urban form and urban size do not develop the same as previously thought. While size generally moves in a single direction, especially in large cities, form can ebb and flow depending on constraints, such as the geography of places as well as environmental and technological factors.

“This (the categorization) is something that is really novel about that paper because this could not be done prior to that because these data were just not available,” said Johannes Uhl, the lead author of the paper and a research associate at CU Boulder.

It’s remarkable, according to the researchers, that the two articles are being published by different high-impact journals on the same day. While the Nature Communications Earth and Environment piece discusses the substantive application of the data, the Earth System Science Data discusses the data themselves, the methods to create them, and the limitations with them.

“There’s so much potential in this current data revolution, as we call it,” Leyk commented. “The growth of so-called data journals is a good trend because it’s becoming more and more systematic to publish formal descriptions of the data, to learn where the data can be found, and to inform the community what kind of publications are based on these data products. So, I like this trend and we try and make use of it.”

This research, however, is still far from finished. Next, the researchers hope to further examine the categories, and, in particular, the different groups of cities that emerged in the process of this research to hopefully determine a classification system for urban evolution, while also applying the data approach to more rural settings.

“The findings are interesting, but they can of course be expanded into greater detail,” Uhl said.

The researchers are also working with other researchers in different fields across the university to explore the applications of these data on topics as far reaching as urban fuel models for nuclear war scenarios, the exposure of the built environment to wildfire risk, and settlement vulnerability from sea level rise.

“The context is a little different in each of these fields, but really interesting,” Leyk said. “You realize how important that kind of new data, new information, can become for so many unexpected topics.”

Republished with permission from the Colorado Arts and Sciences Magazine