Without campus leftovers to pick through, the beaks of this bird changed shape during the pandemic

Urban junco bills at UCLA became more like mountain junco bills

University of California - Los Angeles

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Key takeaways

• Dark-eyed juncos, a bird that typically live in mountain forests, have established thriving populations in Southern California cities, where they eat food people leave behind.

• A UCLA biologist studying the biological adaptations that help them survive an urban environment has found that the bill shape of this species became more like that of their non-urban counterparts in the absence of people during the pandemic closures at UCLA.

• After campus re-opened, the bills gradually returned to their previous shape, suggesting that the presence of people and their trash is driving the evolution of bill shape.

Juncos on the UCLA campus evolved a different bill shape during the pandemic closure, before returning to their previous shape once university life returned to normal, UCLA biologists who have been studying this population of birds for a decade reported in a new study. The finding, published in Proceedings of the National Academy of Sciences, shows how quickly traits can evolve when an important selective pressure is altered — in this case, humans making food easier to find.

“We have this idea of evolution as slow, because in general, over evolutionary time, it is slow,” said corresponding author and UCLA professor of ecology and evolutionary biology Pamela Yeh. “But it’s amazing to be able to see evolution happening before your eyes, and to see a clear human effect changing a living population.”

Dark-eyed juncos are a small member of the sparrow family that usually live in mountain forests. But as climate change shrinks their preferred habitat, Southern California’s juncos have surprised biologists by establishing themselves in cities and suburban neighborhoods. Non-urban juncos forage for seeds, but urban juncos have learned to exploit various crumbs, scraps and food waste that people leave lying around. Yeh’s lab has been banding, observing, measuring and taking blood samples from UCLA’s junco population to understand the adaptations that are making it possible for the birds to flourish in their city digs.

The new study found that during the pandemic closure, UCLA’s junco bills evolved to more closely resemble the bills of their forest relatives. Previously, Yeh and her students had seen relatively short, stubby bills. Over nearly two years of minimal human activity on campus, junco parents raised babies with gradually longer, more slender bills, which are typical of non-urban juncos.

“We were quite shocked, to be honest, when we saw just how strong that change was,” said first author Eleanor Diamant, who did the research as a doctoral student at UCLA and is now a visiting assistant professor at Bard College. “We think that that likely happened because when humans are not around, they’re not leaving their trash around and they’re not leaving their food around.”

At UCLA, juncos love to forage on plazas where students gather, patios around dining venues and walkways. When the food they used to find in these places disappeared in the absence of people, the birds were forced to forage in the more challenging landscape of bushes, grass and leaves like their non-urban counterparts. Leaving campus for easier pickings around supermarkets and the handful of other businesses that remained open during the pandemic closure was not a good option for UCLA’s juncos because these birds do not usually venture far from a territory they defend.

“We think that juncos with different bill shapes were more successful when campus was closed. Those with bills that improved their success at foraging for seeds probably got more food and raised more babies,” said Diamant.

But the change didn’t last. Once campus life returned to normal, the bills returned to their previous shape, which drove home the idea that the presence of people is having a strong effect on the evolution of bill shape in urban juncos.

“Wild animals have to work hard to find and get their food. When humans make it that much easier, the parts of their bodies, such as their mouths, that animals use for foraging adapt,” said Yeh. 

Although no one expected to see this change in juncos, the evolution of shorter snouts in other urban wildlife, such as rats and raccoons, has been documented. Given that an estimated 3 billion birds have vanished over the past 50 years — around 168 million of them juncos — their resilience offers hope for their future survival.

Yeh said that other urban birds like house sparrows and pigeons are in some ways pre-adapted to live with people because of their generalist diet, tendency to live in large flocks  and ability to nest off the ground in human structures. But juncos are territorial, ground-nesting birds that don’t usually thrive in cities.

“The fact that juncos are doing very well, popping up in cities all over Southern California, and that we are unintentionally changing them in a way that helps them survive around us is encouraging,” said Yeh. “I don’t feel like we have a lot of success stories when we think about how human behavior affects wildlife. I wouldn’t fully call it a success story yet, but it’s not a disaster story, and that’s no small thing.”

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Journal

Proceedings of the National Academy of Sciences

 

Nearly three-quarters of western US overdue for wildfires

For a decade, nearly four million hectares per year would need to burn just to catch up

American Geophysical Union

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NEW ORLEANS — Wildfires can benefit forests by clearing old debris, leaving behind fertilizer, and more. For over a century, the United States has poured billions of dollars into fire suppression tactics to keep people, homes and critical environments safe, but suppression can deprive landscapes of necessary burns and increase potential fuel for large fires in the future.

New research to be presented at AGU’s 2025 Annual Meeting in New Orleans has found nearly 38 million hectares of land in the western United States is historically behind on its burning, leaving those lands in a “fire deficit.” This acreage has been updated from 59 million in the abstract to the final number of 38 million.

“Conditions are getting so warm and dry that it’s causing huge amounts of fire compared to the historical record,” said Winslow Hansen, director of the Western Fire and Forest Resilience Collaborative and scientist at Cary Institute of Ecosystem Studies. “However, we still are dealing with the legacy of 150 years of fire suppression. Together, drying conditions and overly dense fuels portend a challenging and more fiery future.”

Hansen will present the findings on 18 December at AGU25, joining more than 20,000 scientists discussing the latest Earth and space science research.

To discover which areas were in a fire deficit or a fire surplus, researchers leveraged geospatial data, like pollen records and dirt samples, to determine historical fire return intervals that were then reconstructed by the Landfire program.

Compared to the historical patterns of annual burn area that emerged in the data, 74% of the western U.S. is currently in a fire deficit. To make up that debt, 3.8 million hectares of forest would need to burn each year over a decade. That yearly burn area is three times the amount of forested area that burned in 2020, the current record year for wildfire burn area in the U.S.

That amount of burning is daunting, but Hansen and his team highlight that multiple strategies could be used. Officials must use a combination of prescribed burns, mechanical thinning and even managed wildfire use to erase the deficit.

“There are still lots of wildfires that burn today… that are reducing our fuel loads and revitalizing ecosystems,” said Hansen. “Instead of suppressing those fires and putting them out, we’ve got to let them do good ecological work to help us tackle this challenge when risk is low.”

While much of the west may be behind on its annual fires, the southwest is facing the opposite problem. Human-started wildfires have spurred a fire surplus in shrublands and chapparal ecosystems, especially in Southern California.

“You’re getting more fire than you would have historically, which can even threaten resilience,” Hansen said. “These shrubland ecosystems might not be able to regenerate if the fire is too frequent.”

Parts of Cascadia are also in a fire surplus due to climate change increasing extreme temperatures and droughts, both of which help set the stage for blazes.

“I was a little bit surprised to see these signals of climate change-driven surplus already,” said Hansen. “I’d expected that would be something we would see in the next decade or two instead.”

Contributed by Riley Thompson

 

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Abstract information:

B42C-08 Erasing the western US forest-fire deficit will require approximately 60 million hectares of ecologically beneficial burning over the next decade.

Thursday, 18 December, 11:45 – 11:55 Central Time

Room 265-266 NOLA Convention Center

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AGU’s Annual Meeting (#AGU25) will bring more than 20,000 Earth and space scientists to the Ernest N. Morial Convention Center in New Orleans, LA from 15-19 December. Members of the press and public information officers can request complimentary press registration for the meeting now through the end of the conference. Learn more about the press AGU25 experience in our online Press Center.

 AGU (www.agu.org) is a global community supporting more than half a million professionals and advocates in Earth and space sciences. Through broad and inclusive partnerships, AGU aims to advance discovery and solution science that accelerate knowledge and create solutions that are ethical, unbiased and respectful of communities and their values. Our programs include serving as a scholarly publisher, convening virtual and in-person events and providing career support. We live our values in everything we do, such as our net zero energy renovated building in Washington, D.C. and our Ethics and Equity Center, which fosters a diverse and inclusive geoscience community to ensure responsible conduct.

 

Autumn clock change linked to reduction in certain health conditions

Study contributes to ongoing debate about England’s clock change policy

BMJ Group

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The week after the autumn clock change is associated with a reduction in demand for NHS services for sleep disorders, cardiovascular disease, anxiety, depression, and psychiatric conditions in England, finds a study in the Christmas issue of The BMJ.

However, there is little evidence that the spring clock change has any short term effect on the number of health conditions, say the researchers.

Daylight saving time was introduced during the first world war and involves moving the clocks one hour forward in spring and one hour back in autumn. It operates in around 70 countries and affects a quarter of the world’s population.

Yet some studies (mainly outside the UK) have suggested that the clock changes, particularly the spring clock change, have a detrimental effect on health, leading to calls for them to be abolished.

To obtain a clearer picture, researchers set out to explore the short term (acute) effects of the clock changes on people’s mental and physical health in England. 

Their findings are based on linked primary and secondary care records for 683,809 people with at least one of eight health events in the weeks surrounding the spring or autumn clock changes from 2008 to 2019. 

The health events analysed were anxiety, major acute cardiovascular disease, depression, eating disorder, road traffic injury, self-harm, or sleep disorder in primary or secondary care or a psychiatric condition in accident and emergency. 

The mean daily number of events (per year, per region) in the first week after the clock changes were compared with those in the control period (four weeks before the changes and weeks 2-4 after).

In the week after the autumn clock change, five health conditions had fewer events: anxiety (a 3% reduction from 17.3 events per day to 16.7), acute cardiovascular disease (a 2% reduction from 50 events per day to 48.9), depression (a 4% reduction from 44.6 to 42.7), psychiatric conditions (a 6% reduction from 3.5 to 3.3), and sleep disorders (an 8% reduction from 5.4 to 4.9).

Little evidence was found of reductions in eating disorder diagnoses, road traffic injuries, or self-harm or of changes after the spring clock change.

This is an observational study, so no firm conclusions can be drawn about cause and effect, and the authors note that health records contain only events for which the individual seeks medical help, and the date that a health event is recorded by a clinician, which is not necessarily the date of symptom onset.

However, they say the results are based on 12 years of broadly representative general practice and hospital data, giving a more complete picture of the effect of the clock changes on demand for health services than previous studies.

They suggest that the extra sleep over the Autumn clock change and the abrupt increase in morning sunlight exposure after the transition may be beneficial to health.

And they conclude: “Our study contributes to the ongoing debate about England’s clock change policy. Future research should explore the mechanisms underlying the reduction in health events that we observed after the autumn clock change.”

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Journal

The BMJ

DOI

10.1136/bmj-2024-085962 

Method of Research

Observational study

Subject of Research

People

Article Title

Acute effects of daylight saving time clock changes on mental and physical health in England: population based retrospective cohort study

Article Publication Date

17-Dec-2025

COI Statement

All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: support from the Wellcome Trust for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

 

Where medicine meets melody – how lullabies help babies and parents in intensive care

Music provides respite from an uncertain and stressful situation, says expert

BMJ Group

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Playing soothing live music in intensive care units not only helps parents bond with their baby but also provides a moment’s respite from an uncertain and stressful situation, says a senior doctor in the Christmas issue of The BMJ.

In 2025, Music in Hospitals & Care has delivered more than 90 hours of live music to neonatal intensive care units (NICUs) in the UK, reaching more than 1000 seriously ill babies.

The charity has been providing soothing tunes for babies and parents through its Lullaby Hour sessions since 2017, bringing a sense of calm to intensive medical settings, including adult intensive care units.

Several studies have found a positive effect of music therapy on preterm babies in the NICU - including lowering heart rate and respiratory rate, as well as increasing feeding volume - although a 2021 meta-analysis highlighted the low certainty of the evidence.

Mica Bernard, singer and guitarist, says: “When I’m singing to the baby, I can literally see their heart rate calming down or their oxygen increasing. I think it goes to show just how built in music is for human beings.”

Contrary to some parents’ concerns, research by Music in Hospitals & Care shows that babies are frequently observed falling asleep or staying asleep during the live music. Sometimes it’s played during distressing times such as clinical procedures and nappy changes.

Jay Banerjee, neonatal consultant at the Imperial College Healthcare NHS Trust, says: “These music sessions not only help parents bond with their baby but also provide a moment’s respite from an uncertain and stressful situation. The feedback from families and the clinical team here has been universally positive.”

The bonding element of Lullaby Hour is particularly important for parents who can’t hold their baby who is in an incubator.

Bernard explains: “Often, if it’s the first time I’ve sung to a parent, it’s the perfect outlet for them to be able to cry … The music helps them get in touch with what they’re feeling.”

The music also provides some sense of normality in intensive care wards.

Gail Scott-Spicer, chief executive of Imperial Health Charity, which delivers arts programmes to hospitals, says: “The environment of a neonatal intensive care unit is, of course, quite overwhelming … To be able to bring a bit of ‘normal’ into that situation starts to explain the really positive health outcomes for the babies, and it reduces stress and anxiety for the families.”

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DOI

10.1136/bmj.r2587 

Method of Research

Commentary/editorial

Subject of Research

People

Article Title

Where medicine meets melody—Lullaby Hour brings harmony to the neonatal ICU

Article Publication Date

17-Dec-2025

COI Statement