The changing chorus: How movements and memories influence birdsong evolution

University of Oxford

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Great Tit in Wytham Woods. Credit: David López Idiáquez

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Credit: David López Idiáquez

New research from the University of Oxford has provided fresh insights into how bird songs evolve over time, revealing a significant role for population dynamics in shaping song diversity and change. The findings – based on an analysis of over 100,000 bird songs – have been published today (7 March) in the journal Current Biology. 

The researchers spent three years collecting over twenty thousand hours of sound recordings from a wild population of great tits (Parus major) in Oxfordshire, which has been studied for the past 77 years as part of the Wytham Great Tit study. Their aim was to investigate how the movement, age, and turnover of birds within a population influences the diversity and evolution of their songs – including which songs become locally popular, which fade away, and how varied their song repertoires become. 

To achieve this, they used a new approach involving training an AI model to recognise individual birds based on their songs alone and measure song differences between individuals. This method allowed them to track variations in song repertoires across the population and uncover patterns in song evolution. 

The results showed that birds of similar age tend to have more similar repertoires, with mixed-age neighbourhoods having higher cultural diversity. Furthermore, the pace of song turnover within neighbourhoods is driven by individuals coming and going; when birds leave or die, many song types disappear with them and the young birds that replace them can speed up the adoption of new song types. 

At the same time age serves as a brake on change, as older birds continue to sing song types that are becoming less frequent in the population. In this way, older birds can function as ‘cultural repositories’ of older song types that younger birds may not know, just as grandparents might remember songs that today's teenagers have never heard.

However, age is not the sole factor influencing song change. The study also found that when birds mix more – through increased local dispersal and the arrival of immigrants – they tend to adopt more common songs, which also slows the pace of song evolution. 

Furthermore, ‘homegrown’ songs tend to stay unique: Areas where birds stay close to their birthplace maintain more diverse and unique song cultures, similar to how isolated human communities often develop distinct dialects or musical styles.   

The results also indicated that newcomers tend to adapt but also enrich song diversity. Immigrant birds arriving from elsewhere typically adopt local songs rather than introducing entirely new tunes, however they tend to learn more songs overall, enriching the local ‘musical scene.’   

Lead researcher Dr Nilo Merino Recalde (Department of Biology, University of Oxford) said: “Just as human communities develop distinct dialects and musical traditions, some birds also have local song cultures that evolve over time. Our study shows exactly how population dynamics - the comings and goings of individual birds - affect this cultural learning process, influencing both song diversity and the pace of change." 

The study is the first extensive test of the role of demography in driving cultural diversity and evolution at small scales in a wild animal population, using individual-level data and a very large dataset on song variation. This research not only provides insights into bird behaviour but also offers valuable perspectives on how demographic changes might affect cultural evolution across animal species - with potential implications for conservation efforts. The complete dataset has been made publicly available for other researchers to explore.   

Professor Ben Sheldon (Department of Biology, University of Oxford), who leads the long-term bird study in Wytham Woods, commented: “Our work here shows, once again, that tracking individuals over their lives allows us to understand so much of the way that different processes interact in natural populations. It’s thrilling to think that we can explain the acoustic landscape we hear in the woods each spring in terms of the result of the cumulative combination of individual movements and survival over many years.” 

Notes to editors 

Interviews with Dr Nilo Merino Recalde are available on request: nilo.recalde@biology.ox.ac.uk 

The paper ‘The demographic drivers of cultural evolution in bird song’ will be published in Current Biology at 16:00 GMT / 11:00 ET Friday 7 March 2025. It will be available online when the embargo lifts at DOI 10.1016/j.cub.2025.02.016

To view a copy of the paper before this under embargo, contact nilo.recalde@biology.ox.ac.uk 

About the University of Oxford 

Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the ninth year running, and ​number 3 in the QS World Rankings 2024. At the heart of this success are the twin-pillars of our ground-breaking research and innovation and our distinctive educational offer. 

Oxford is world-famous for research and teaching excellence and home to some of the most talented people from across the globe. Our work helps the lives of millions, solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research alongside our personalised approach to teaching sparks imaginative and inventive insights and solutions. 

Through its research commercialisation arm, Oxford University Innovation, Oxford is the highest university patent filer in the UK and is ranked first in the UK for university spinouts, having created more than 300 new companies since 1988. Over a third of these companies have been created in the past five years. The university is a catalyst for prosperity in Oxfordshire and the United Kingdom, contributing £15.7 billion to the UK economy in 2018/19, and supports more than 28,000 full time jobs. 

The Department of Biology is a University of Oxford department within the Maths, Physical, and Life Sciences Division. It utilises academic strength in a broad range of bioscience disciplines to tackle global challenges such as food security, biodiversity loss, climate change and global pandemics. It also helps to train and equip the biologists of the future through holistic undergraduate and graduate courses. For more information visit www.biology.ox.ac.uk  

Great Tit in Wytham Woods. Credit: David López Idiáquez

Great Tit. Credit: Nilo Merino Recalde.

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Journal

Current Biology

DOI

10.1016/j.cub.2025.02.016 

Article Title

The demographic drivers of cultural evolution in bird song

Article Publication Date

7-Mar-2025

 

Direct exposure to mass shootings among US adults

JAMA Network Open

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About The Study: 

The findings from this survey study of U.S. adults underscore the extensive and often overlooked regular exposure to mass shootings in this country. The demographic disparities in exposure highlight the need for targeted interventions and support for the most affected groups, particularly younger generations and males. Understanding these patterns is essential for addressing the broader impacts of gun violence on public health and community well-being.

Corresponding Author: To contact the corresponding author, David C. Pyrooz, PhD, email david.pyrooz@colorado.edu.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2025.0283)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time https://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2025.0283?guestAccessKey=c0957767-f5eb-4d6d-88a4-15c747418b57&utm_source=for_the_media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=030725

About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication. 

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Journal

JAMA Network Open

One in 15 U.S. adults have been on the scene of a mass shooting

A new study highlights how far-reaching the impacts are and calls for more support for those affected

University of Colorado at Boulder

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About 7% of U.S. adults have been present at the scene of a mass shooting in their lifetime, and more than 2% have been injured during one, according to new University of Colorado Boulder research.

The study, published March 7 in the journal JAMA Network Open, also found that younger generations were significantly more likely to have been exposed than their parents or grandparents were.

Generation Z— adults born after 1996—were at greatest risk.

“This study confirms that mass shootings are not isolated tragedies, but rather a reality that reaches a substantial portion of the population, with profound physical and psychological consequences,” said senior author David Pyrooz, a professor of sociology and criminologist in the Institute for Behavioral Science at CU Boulder. “They also highlight the need for interventions and support for the most affected groups.”   

                                                            
A ripple effect

For the study, Pyrooz and his colleagues surveyed a nationally representative sample of 10,000 adults in January 2024. (The researchers chose January because the month tends to see a lull in mass shootings). They asked them a series of questions, including: “Have you personally ever been physically present on the scene of a mass shooting in your lifetime?”

The group defined “mass shooting” as a gun-related crime where four or more people were shot in a public space. The researchers defined “physically present”  as “in the immediate vicinity of where the shooting occurred at the time it occurred, such that bullets were fired in your direction, you could see the shooter, or you could hear the gunfire.”

Just under 7% of respondents answered yes. Just over 2% of respondents said they had been injured, which not only includes having been shot, but also hit by shrapnel, trampled by people fleeing the scene or other injuries.

“We are talking about one out of every 15 people in the United States,” said Pyrooz. “These are really high numbers for this seemingly unique and small subset of gun violence,” said Pyrooz.

While these numbers might seem high, Pyrooz said he was not surprised by the survey results. A single mass shooting can impact far more people than many realize.

For instance, during the 2017 shooting at the Route 91 Harvest Music festival in Las Vegas, the shooter killed 60 people and wounded 413 others. But another 454 people were injured during the ensuing panic as people fled to safety. In all, there were about 22,000 people at the concert—plus onlookers from surrounding hotels on the Las Vegas strip.

“That translates to about one out of every 11,000 Americans who were on the scene of that shooting alone,” said Pyrooz. “Continue that to other events that have occurred around the country and the numbers, unfortunately, add up.”

The ‘mass shooting generation’

Black people and males were more likely to have witnessed a mass shooting.

More than half of the respondents who had been present during a mass shooting said it happened in the last decade—a finding that reaffirms the notion that younger generations are experiencing a cultural phenomenon their parents didn’t have to deal with.

“Our findings lend credence to the idea of a ‘mass shooting generation,’” said Pyrooz. “People who grew up in the aftermath of Columbine have these unique experiences that are really distinguishable from the older population.”

Three-quarters of the respondents experienced mass shootings in their local communities—in places like bars or restaurants, schools, shopping outlets and synagogues.

The income and education level of respondents had no measurable impact on their chances of being present, or injured, at a mass shooting.

The aftermath

The study did not quantify how mass shootings impact mental health, but Pyrooz and his colleagues are publishing a forthcoming paper that will.

It found that about three-quarters of those who were present at the scene of a mass shooting but uninjured still experienced psychological distress, including fear, anxiety and depression. (For comparison, about 20% of people in the general population report these symptoms.)

Pyrooz hopes the ongoing research will help fill a research gap around the public health impacts of the relatively new, and understudied, phenomenon of mass shootings. He also hopes it will underscore the need to support programs aimed at reducing gun violence, and bolster supporting those suffering lingering effects from exposure.

He can still remember the sound of the sirens from the March 22, 2021 mass shooting at a King Soopers just miles from his office in Boulder.

He wasn’t personally exposed but knows what a toll it took on his own community.

“It’s not a question of if one will occur in your community anymore, but when,” he said. “We need to have stronger systems in place to care for people in the aftermath of this tragic violence.”

 

 

 

 

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DOI

10.1001/jamanetworkopen.2025.0283 

Method of Research

Survey

Subject of Research

People

Article Title

Direct Exposure to Mass Shootings Among US Adults

Article Publication Date

7-Mar-2025

 

KTU scientists develop advanced forest monitoring systems: Will forests monitor themselves in the future?

 Climate change, pests, and human activity are transforming forests faster than we can track them – some changes become apparent only when the damage is already irreversible.

Kaunas University of Technology

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image: 

For example, Figure 1 displays a normalized sound waveform of bird sounds recorded in an urban forest
under windy conditions. Of course, this waveform is a mixture of the signals present there. However,
the signals at work can be seen using signal processing and reviewing the time and frequency domains (as
represented in Figure 2). Bird chirpings, which tend to be at high frequencies, and the sound of the wind
passing through the forest were seen in different groups.

view more 

Credit: KTU

“Forests are among the most important ecosystems in nature, constantly evolving, yet their monitoring is often delayed,” says Rytis Maskeliūnas, a professor at Kaunas University of Technology (KTU). Climate change, pests, and human activity are transforming forests faster than we can track them – some changes become apparent only when the damage is already irreversible.

KTU researchers are proposing innovative technological solutions: an innovative forest regeneration model and a sound analysis system that can predict forest conditions and detect environmental changes in real time.

Forest management today is increasingly challenged by environmental changes that have intensified in recent years. “Forests, especially in regions like Lithuania, are highly sensitive to rising winter temperatures. A combination of factors is causing trees to weaken, making them more vulnerable to pests,” says Maskeliūnas.

According to the scientist, traditional monitoring methods such as foresters’ visual inspections or trap-based monitoring are no longer sufficient. “We will never have enough people to continuously observe what is happening in forests,” he explains.

To improve forest protection, KTU researchers have employed artificial intelligence (AI) and data analysis. These technologies enable not only real-time forest monitoring but also predictive analysis, allowing early intervention in response to environmental changes.

Spruce trees are particularly affected by climate change

One key solution is the forest regeneration dynamics model, which forecasts how forests will grow and change over time. The model tracks tree age groups and calculates probabilities for tree transitions from one age group to another by analysing growth and mortality rates.

Head of the Real time computer center (RLKSC), data analysis expert, Prof. Robertas Damaševičius, identifies core advantages of the model: it can identify which tree species are best suited to different environments and where they should be planted.

“It can assist in planning mixed forest replanting to enhance resilience against climate change, as well as predict where and when certain species might become more vulnerable to pests, enabling preventive measures. This tool supports forest conservation, biodiversity maintenance, and ecosystem services by optimising funding allocation and compensation for forest owners,” says Maskeliūnas.

The model is based on advanced statistical methods. The Markov chain model calculates how a forest transitions from one state to another, based on current conditions and probabilistic growth and mortality rates. “This allows us to predict how many young trees will survive or die due to diseases or pests, helping to make more informed forest management decisions,” explains KTU’s Faculty of Informatics professor.

Additionally, a multidirectional time series decomposition distinguishes long-term trends in forest growth from seasonal changes or unexpected environmental factors such as droughts or pest outbreaks. Combining these methods provides a more comprehensive view of forest ecosystems, allowing for more accurate forecasting under different environmental conditions.

The model has also been applied to assess Lithuania’s forest situation, revealing that spruce trees are particularly affected by climate change, becoming increasingly vulnerable due to longer dry periods in summer and warmer winters. “Spruce trees, although they grow rapidly in young forests, experience higher mortality rates in later life stages. This is linked to reduced resistance to environmental stress,” says Maskeliūnas.

Forest sounds reveal ecosystem health

Another tool developed by the researchers is a sound analysis system that can identify natural forest sounds and detect anomalies that may indicate ecosystem disturbances or human activity. Sound analysis is becoming an important part of forest digitisation, allowing real-time environmental monitoring and faster response to potential threats.

The model, proposed by KTU RLKSC PhD student Ahmad Qurthobi, is innovative in combining a convolutional neural network (CNN) with a bi-directional long short-term memory (BiLSTM) model.

“CNN recognises and provides features that describe sound, yet it is not enough to understand how sounds change over time. That’s why we use BiLSTM, which analyses temporal sequences,” explains Maskeliūnas.

This hybrid model not only accurately detects static sounds, such as the constant chirping of birds, but also identifies dynamic changes, such as sudden deforestation noises or shifts in wind intensity.

“For example, bird songs help monitor their activity, species diversity and seasonal changes in migration. A sudden decrease or significant increase in bird sounds can signal ecological problems,” says Maskeliūnas.

Even tree-generated sounds, such as those caused by wind, leaf movement, or breaking branches, can indicate wind strength or structural changes in trees due to drought or other stressors.

Researchers agree that the model could also be adapted for monitoring other environmental changes: “Our model could detect animal sounds such as wolf howls, deer mating calls, or wild boar activity, helping to monitor their movement and behaviour patterns. In urban areas, it could be used to track noise pollution or intensity”.

The solution itself is not just an innovation on paper. The sound analysis system easily integrates into the KTU developed smart forest Internet of Things (IoT) – Forest 4.0.

“The Forest 4.0 IoT devices are like silent guardians of tomorrow’s ecosystems, analysing the heartbeat of our forests in real time and fostering a world where technology listens to nature,” KTU IoT expert Prof. Egidijus Kazanavičius explains.

Currently, some of the models used by foresters tend to oversimplify complex ecological dynamics and fail to consider species competition, environmental feedback loops, and climate variability. As a result, accurately predicting how forests will respond to different factors remains a challenge.

“This is why these advanced technologies represent the future of forest management,” concludes Prof. Maskeliūnas.

The above-described studies are explained in detail in the following publications: Modeling Forest Regeneration Dynamics: Estimating Regeneration, Growth, and Mortality Rates in Lithuanian Forests, which can be accessed here and Robust Forest Sound Classification Using Pareto-Mordukhovich Optimized MFCC in Environmental Monitoring, which can be accessed here.

Figure 2 – Spectrogram of bird sound (IMAGE)

Kaunas University of Technology

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For example, Figure 1 displays a normalized sound waveform of bird sounds recorded in an urban forest
under windy conditions. Of course, this waveform is a mixture of the signals present there. However,
the signals at work can be seen using signal processing and reviewing the time and frequency domains (as
represented in Figure 2). Bird chirpings, which tend to be at high frequencies, and the sound of the wind
passing through the forest were seen in different groups.

Rytis Maskeliūnas, a professor at Kaunas University of Technology (KTU)

Credit

KTU

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Journal

Forests

DOI

10.3390/f16020192 

Article Title

Modeling Forest Regeneration Dynamics: Estimating Regeneration, Growth, and Mortality Rates in Lithuanian Forests