Fire provides long-lasting benefits to bird populations in Sierra Nevada National Parks
Low to moderate-severity fires boost bird populations for decades
image:
The photo was taken in early May of 2023, about 10 years after this patch of forest in Yosemite National Park burned in the 2013 Rim Fire. Photo by Robert Wilkerson.
view moreCredit: Robert Wilkerson
Researchers have found that low to moderate-severity fires not only benefit many bird species in the Sierra Nevada, but these benefits may persist for decades. In addition to a handful of bird species already known to be “post-fire specialists”, a broad variety of other more generalist species, like Dark-eyed Juncos and Mountain Chickadees, clearly benefited from wildfire. This research will help land managers make decisions about how to manage forests and fires as they face a changing fire regime.
In the study, published October 9, 2025 in the journal Fire Ecology, researchers from The Institute for Bird Populations, the National Park Service, and UCLA examined bird monitoring data spanning two decades from Yosemite, Sequoia, and Kings Canyon National Parks for 42 species, and high-resolution fire history data for up to 35 years before the collection of the bird data. They found that 28 of the 42 bird species had higher population densities in areas that had been burned, and for most of these species, population densities remained higher for decades after the fire. The positive effect of fire lasted for at least 35 years for 11 species. Only 5 of the 42 species showed a negative (1 species) or mixed effects (4 species) of fire on population density.
In the last few decades, the fire regime in the Sierra Nevada has been changing. Historically, fires in the region were more frequent, low and mixed-severity fires often managed by Indigenous people. These fires helped maintain forests dominated by larger, older trees with more open understories. After the 1870s, settlers ended Indigenous cultural burning practices and began suppressing naturally occurring fires. More recently, a warmer climate, increased drought, and the accumulation of fuel due to this fire suppression have increased the extent and frequency of high-severity fire on the Sierra landscape. Now, forest managers throughout much of the region are using controlled burns and other fuel reduction techniques to try to stall the current trend towards large, high-severity fires, sometimes referred to as “megafires.”
The benefits of certain types of fire for wildlife are increasingly recognized, but lead author Dr. Chris Ray, of The Institute for Bird Populations, said the researchers were most surprised by how long fire affected bird abundance. “Given the effects of fire on the nature and structure of bird habitats, and the long post-fire process of vegetative succession, maybe it's not too surprising that birds are responding to fires for so long,” says Ray. “But even low-severity burns had lasting effects on some species: for example, Western Tanager and Hermit Warbler were much more abundant at points that had experienced a low-severity burn 35 years ago than at points that never burned in the previous 35 years.”
Ray emphasizes that 97.5% of the study’s sampling locations in burned areas were in low to moderate severity burns. “Our results don't necessarily apply to the very large and high-severity fires that have been occurring more often in these landscapes in recent years,” she notes. Likewise, the 42 bird species included in this study were relatively common ones, so “these results don't necessarily apply to some of the species that are rare in these landscapes, because we couldn't apply our data-hungry statistical models to species that we didn't observe very often.”
These results suggest that managing forests to create a mosaic of fire return intervals and burn severities, also known as “pyrodiversity,” should benefit the majority of the birds in the forest. Ray notes that there was a strong trend toward more positive effects in burns of moderate severity, compared with burns of low severity. “Land managers might be heartened to hear that many birds might benefit even from burns that aren't all low-severity,” says Ray.
This study would not have been possible without the National Park Service’s Inventory and Monitoring (I & M) Program. The bird population density data used in this study were collected as part of the program, which conducts long-term ecological monitoring within the parks. Since 1998, the I & M Program has gathered information that helps park managers make sound, data-backed decisions. I & M data is also a valuable resource for scientists studying ecological processes, like fire, in the National Parks, which can serve as natural laboratories that are relatively undisturbed by human activities. Unfortunately, funding for The Institute for Bird Populations to conduct the bird monitoring portion of the Inventory and Monitoring Program in the Sierra Nevada parks was cut following the 2025 field season.
A male Western Tanager perches on a burned branch. Western Tanagers were one of many species in the study that appeared to benefit from fire. Photo by Julio Mulero.
A male Hermit Warbler. Hermit Warblers were one of several species in this study that appeared to benefit from fire. Photo by Frank D. Lospalluto.
A Mountain Chickadee. Photo by Daniel Arndt. Mountain Chickadees were one of several species in the study that appeared to benefit from fire.
Journal
Fire Ecology
Method of Research
Data/statistical analysis
Subject of Research
Animals
Article Title
Fire gives avian populations a rapid and enduring boost in protected forests of California
Article Publication Date
9-Oct-2025
Total solar eclipse triggers dawn behavior in birds
Summary author: Walter Beckwith
When the April 2024 “Great American Eclipse” plunged midday into near-night, the daily rhythms and vocal behaviors of many bird species shifted dramatically; some fell silent, others burst into song, and many erupted into a “false dawn chorus” after the Sun returned, singing as if a new day had begun. In a new study, merging citizen science, machine learning, and a continent-wide natural experiment, researchers reveal the immediate effects of light disruption on bird behavior. The daily and seasonal rhythms of birds are tightly governed by shifts between light and dark. But what happens when those cycles are suddenly interrupted, such as during a total solar eclipse? Although past studies have sought to understand the effects of solar eclipses on animal behavior, most have offered only scattered or anecdotal glimpses of how animals respond. Liz Aguilar and colleagues saw the April 2024 total eclipse, which cast nearly 4 minutes of daytime darkness across a large swath of the central and eastern United States, as a rare opportunity to investigate, providing an unprecedented natural experiment in how birds react to abrupt changes in light.
In anticipation of the April 2024 total eclipse, which cast nearly 4 minutes of daytime darkness across a large swath of the central , Aguilar et al. created SolarBird, a smartphone app that allowed users to record bird behavior during the eclipse in real time. Its use by citizen scientists generated nearly 10,000 observations spanning 5,000 kilometers of the eclipse’s path. At the same time, Aguiilar et al. deployed autonomous recording units at sites across southern Indiana, which captured ~100,000 bird vocalizations before, during, and after totality. These recordings were analyzed with BirdNET, an AI system capable of identifying species calls and quantifying vocal activity. According to the findings, of 52 species detected, 29 showed significant changes in their vocal behavior at some point during the event, yet the eclipse did not affect all species equally. In the minutes leading up to totality, 11 species sang more than usual as the sky darkened. During the four minutes of darkness, 12 species responded, with some falling silent while others grew more active. The strongest reactions came after the Sun returned, when 19 species changed their songs in what resembled a false dawn chorus. Barred owls called four times more often than usual, while robins – who are well known for their pre-dawn songs – sang at six times their usual rate. According to Aguilar et al., these patterns suggest that the eclipse temporarily reset some birds’ biological clocks, prompting them to behave as though a new day had just begun.
For reporters interested in trends, an August 2025 Science Research Article shows how light pollution has affected the vocal behavior of birds. According to the findings of Brent Pease et al., birds were generally vocal for nearly an hour longer when in the presence of light pollution, particularly for species with large eyes, open nests, migratory habits, and large ranges and during the breeding season.
Podcast: A segment of Science's weekly podcast with Liz Aguilar and Kimberly Rosvall, related to this research, will be available on the Science.org podcast landing page after the embargo lifts. Reporters are free to make use of the segments for broadcast purposes and/or quote from them – with appropriate attribution (i.e., cite "Science podcast"). Please note that the file itself should not be posted to any other Web site.
Journal
Science
Article Title
The importance of light for bird behavior, as revealed by community science and the 2024 eclipse
Article Publication Date
9-Oct-2025
Research conducted during 2024 eclipse reveals importance of light on bird behavior
Indiana University scientists and the public joined forces during the 2024 solar eclipse to understand the effect of total eclipse on wild birds
Indiana University
image:
From left, Paul Macklin, Liz Aguilar, Ryan Jacobson and Sean Dixit collaborate on the Solar Bird app design at Indiana University. Photo by James Brosher, Indiana University
view moreCredit: James Brosher, Indiana University
Total solar eclipses only happen in the same spot once every 300 or 400 years, so it’s no surprise that a team of researchers at Indiana University jumped on the opportunity to use this natural experiment to better understand how light affects wild birds.
Their study, led by Liz Aguilar, was published in the latest edition of Science. Aguilar is a Ph.D. student in Kimberly Rosvall’s lab in the Evolution, Ecology and Behavior program at the College of Arts and Sciences at IU Bloomington.
In a large collaboration spanning the continent, including the Luddy School of Informatics, Computing, and Engineering, researchers discovered that even when night comes at the wrong time of day and only lasts for about four minutes, many bird species sing as if it were dawn.
The paper showcases their findings from the April 8, 2024 total solar eclipse, when the moon’s shadow raced across North America, from Mazatlán to Newfoundland in just a couple of hours. In Bloomington, the eclipse lasted four minutes and 15 seconds.
The team’s unique collaboration all started when Jo Anne Tracy, College of Arts and Sciences Assistant Dean for Research and Director for Science Outreach, brought together educators to brainstorm how to enhance public engagement in science during the eclipse. This ultimately led Aguilar to partner with Paul Macklin, professor of Intelligent Systems Engineering at the Luddy School of Informatics, Computing and Engineering at IU Bloomington.
Their goal was to create a free smartphone app, SolarBird, to engage the public actively in data collection, while staying true to the very best of animal behavior science. “Scientists can’t be in a thousand places at once,” Aguilar said. “The app gets around this problem by leveraging the public as scientists. It also encourages people to look around and listen, adding to the show in the sky.”
SolarBird users were asked to find a bird and observe it for 30 seconds before, during and after totality. They documented the bird’s behavior by clicking up to 10 boxes on the app, such as singing, eating or flying.
“A main theme was how we could make data collection easy for newcomers, and minimize any distractions from the day’s event,” Macklin said. “We used the smartphone’s GPS coordinates and known formulas to determine the eclipse phase, which is the percentage of sun obscured by the moon.”
Aguilar lights up when recalling the moment she saw the initial SolarBird results. “We got nearly 11,000 observations from more than 1,700 users, concentrated along the path of totality across the continent. It was important to us to publish their names in our paper.”
“It was wonderful,” Macklin said. “The app worked. And as we looked at the database that night, we saw the community had also worked its magic.”
While the app team worked feverishly to get the app deployed and approved on the Android and Apple stores, Rosvall led a separate team using automated recorders to listen to bird vocalizations in Bloomington and surrounding rural areas in the week leading up to the eclipse. These recording units – about the size of a tissue box – collected massive amounts of information.
Dustin Reichard, an alumni of the Evolution, Ecology and Behavior graduate program, helped deploy the recorders and analyze the data. Now faculty at Ohio Wesleyan University, Reichard studies animal communication, including the songs that birds use to attract mates or secure territories in the spring.
Reichard said the team used an artificial neural network called BirdNET – the same AI network used by the Merlin app that many people have on their phones – to scan many hours of recordings and identify which birds were singing before, during, and after totality. The team was able to analyze almost 100,000 bird vocalizations in record time.
Coupled with validations by the team’s expert birder, a data science specialist and more on-the-ground support, they focused on 52 abundant species, with 29 species showing a clear change in how much they vocalized before, during or after the total solar eclipse.
“Even a very brief disruption in light – just over four minutes in this case – can cause large changes in behavior, especially for species that naturally produce a burst of song around dawn,” Reichard said.
A year and a half later, you can still hear the wonder in Rosvall’s voice as she describes the project. “It’s crazy that you can turn off the Sun, even briefly, and birds’ physiology is so tuned to those changes that they act like it’s morning. This has important implications on the impact of urbanization or artificial light at night, which are much more widespread.”
“A lot had to align for this to work: that the eclipse would peak in this area at this time of year; that IU is a center of animal behavior research known internationally; and that we had the people, the tools, and the public’s interest,” Reichard said. “Everything came together.”
The team’s combination of passive sound recording, AI-supported analysis and community science opens exciting possibilities for the future, Rosvall said.
She hopes their success will encourage more scientists to engage in projects that combine AI and community science so that the public can see themselves as scientists to learn more about the world. “It was clear that engaging in this research project enhanced people’s joy in this experience,” she said. “It did for me and those who reached out.”
Rosvall, Reichard and Macklin said it was one of the most rewarding projects they have ever done. Aguilar agreed, calling it “the work she’s most proud of.”
“It shows that sometimes a creative idea and a willingness to go all in is what you need to accomplish high-impact work,” Rosvall said.
This project was supported by grants from the Indiana Space Grant Consortium and the National Science Foundation.
Indiana University Ph.D. student Liz Aguilar and associate professor Kim Rosvall in the College of Arts and Sciences connected with experts at the Luddy School of Informatics, Computing and Engineering in Bloomington through the Office of Science Outreach to develop the Solar Bird app. Photo by James Brosher, Indiana University
Credit
James Brosher, Indiana University
Journal
Science
Method of Research
Observational study
Subject of Research
Animals
Article Title
The importance of light for bird behavior, as revealed by community science and the 2024 eclipse
Article Publication Date
9-Oct-2025
These songbirds learn more from siblings than from parents
When parental care is limited, siblings and others step up
University of California - Davis
image:
A European great tit flies off with a mealworm after solving a sliding door foraging puzzle.
view moreCredit: Sonja Wild, UC Davis
Siblings are special. Be they protector or tormentor, friend or foe, the relationship between siblings is like no other. They witness each other’s childhoods — sharing parents, history, secrets and advice.
Even among some bird species, siblings can be powerful role models — eclipsing even their parents’ influence — according to a study from the University of California, Davis, and the Max Planck Institute of Animal Behavior.
The study, published in the journal PLOS Biology, is the first to examine social learning strategies in juveniles in the wild where the species has some, but not extensive, parental care.
“Much of our knowledge about social learning in juveniles stems from species with extended periods of parental care, including humans,” said lead author Sonja Wild, who was a postdoctoral research associate with UC Davis and the Max Planck Institute when the study was conducted. “A lot of learning occurs from parents because offspring and parents spend so much time together. But what happens with knowledge transfer when parental care is limited?”
Learning life skills
Using the songbird Parus major, commonly known as the great tit, as a model species, the researchers found that siblings and other adults can be key sources for learning life skills when parents are rarely present. This alternative pathway helps explain behavioral similarities in families with limited parental input.
“When they leave the nest, they know nothing,” Wild said of the species. “They can’t feed themselves or find shelter. All they have is about 10 days of parental care to figure everything out. The offspring would like to extend that time. They follow their parents around and keep begging, but the parents are exhausted and start pulling back. So the selection pressures are really strong for offspring to quickly figure out how to find food themselves.”
Puzzling behavior
To understand the social learning strategies of the young birds, the authors presented 51 breeding pairs and their 229 newly fledged offspring with feeding puzzles for 10 weeks. The birds could solve the puzzles by sliding a door to the left or right to reach a tray of mealworms.
“Fully automated puzzle boxes allowed us to collect high-resolution data on hundreds of microchipped birds,” Wild said. “This produced tens of thousands of solves that helped disentangle the pathways of learning and the decision-making strategies the juveniles employed during their transition to independence.”
After tracking the birds’ solving behavior for 10 weeks, they found the birds were more likely to learn to solve the puzzle if their parents were skilled at solving it. However, the young birds’ solution strategies were much more strongly influenced by how their siblings and non-parent adults solved the puzzle.
Of the first learners of each sibling group, nearly 75% learned from adults who were not their parents, while about 25% learned from their parents. Of the subsequent learners in each group, about 94% learned to solve the puzzle from their siblings.
Resilience and conservation
Understanding animal behavior can be valuable for biodiversity and wildlife conservation.
“The more diverse animal cultures are, the more resilient populations are to extinction and able to deal with environmental fluctuations,” Wild said. “Such species are less vulnerable because they have many different role models from which to get cultural and socially learned information.”
The study’s additional coauthors include Gustavo Alarcón-Nieto from the Max Planck Institute and Lucy Aplin from the Australian National University, Max Planck Institute and University of Zurich.
The study was funded by German Research Foundation and a Max Planck Society Group Leader Fellowship.
Journal
PLOS Biology
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Siblings and non-parental adults provide alternative pathways to cultural inheritance in juvenile great tits
Article Publication Date
9-Oct-2025
Young birds learn life skills from their older siblings and flock mates
European great tits learn puzzle-solving technique not only from their parents, but from other birds
PLOS
image:
A juvenile great tit solves a foraging puzzle by pushing a sliding door to the left while being observed by two other juvenile birds.
view moreCredit: Sonja Wild (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
Newly hatched European great tits learn life skills less from their parents and more from siblings and other flock mates, according to a study published October 9th in the open-access journal PLOS Biology by Sonja Wild of the Max Planck Institute of Animal Behavior, Germany, and colleagues.
In many species, young individuals learn essential life skills by observing or interacting with their parents. But less is known about early learning habits in species with limited parental interactions. In this study, Wild and colleagues observe learning patterns in young European great tits, which spend only a few weeks being dependent on their parents.
51 breeding pairs of birds and their 229 offspring were presented with two-solution feeding puzzles which could be solved by sliding a door either to the left or right. The authors found that young birds were more likely to learn to solve the puzzle if they had parents who were skilled at solving it, suggesting that offspring learned from their parents. However, young birds were most likely to learn from already knowledgeable siblings and non-parental adults with only limited input from parents. In fact, young birds who were not the oldest of their cohort appear to have learned solutions almost entirely (>90%) from their older siblings.
These results provide an example of multi-generational knowledge that does not rely primarily on transmission from parents to offspring, highlighting the importance of siblings and flock mates in the learning process of great tits. The authors suggest that future studies might investigate how learning is influenced by other factors such as environmental conditions and developmental stress.
The authors add, “In many animal species, juveniles rely on their parents for learning behaviors, a process called cultural inheritance that leads to behavioral similarities within family units. Using songbirds as a study system, we show that in species with limited parental care, siblings can be key sources for learning new behaviors, which provides an alternative pathway to cultural inheritance that can explain behavioral similarities in families even with minimal parental input.
“Our fully automated puzzle boxes allowed us to collect high-resolution data on hundreds of micro-chipped birds producing tens of thousands of solves to really disentangle the pathways of learning and the decision-making strategies the juveniles employed during transition to independence.
“Great tits have become a model organism for questions revolving around sociality and learning, but very few studies have focused on the juvenile period even though it is under strong selection and juveniles need to acquire new knowledge efficiently. Accordingly, we did not really know whether juvenile birds would even learn to solve the puzzle but were soon amazed to see how eagerly they participated in our experiments. They went through 33 kg of mealworms in just a few weeks!”
In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: https://plos.io/4mti8zz
Citation: Wild S, Alarcón-Nieto G, Aplin LM (2025) Siblings and nonparental adults provide alternative pathways to cultural inheritance in juvenile great tits. PLoS Biol 23(10): e3003401. https://doi.org/10.1371/journal.pbio.3003401
Author countries: Germany, United States, Switzerland, Australia
Funding: This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation - https://www.dfg.de/en/research-funding/funding-initiative/excellence-strategy) under Germany’s Excellence Strategy (grant number EXC 2117—422037984) and a Max Planck Society Group Leader Fellowship (https://www.mpg.de/max-planck-research-groups) to LMA. LMA is currently supported by the Swiss State Secretariat for Education, Research and Innovation (SERI—https://www.sbfi.admin.ch/en) under contract number MB22.00056. SW was supported by a Swiss National Science Foundation postdoc mobility fellowship (https://www.snf.ch/en/XIZpfY3iVS5KRRoD/funding/careers/postdoc-mobility) during preparation of this manuscript (grant number P500PB_210994). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Journal
PLOS Biology
Method of Research
Experimental study
Subject of Research
Animals
COI Statement
Competing interests: The authors have declared that no competing interests exist.
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