The study, led by Cristian Pérez-Granados and an international team of ornithologists, set out to do something rarely attempted: compare how songs and calls, the two main categories of bird vocalizations, respond to individual, population, and geographic factors within the same species. Songs are typically complex, learned, and tied to sexual selection, while calls tend to be shorter, more innate, and used for immediate communication such as territorial defense. Because these signals follow different developmental pathways, the team reasoned they might respond differently to habitat fragmentation, population size, and social isolation, providing complementary windows into population health.

Dupont’s lark proved an ideal model. Males sing and give territorial calls at high rates during the hour before dawn, and the species’ communication system is already known to be shaped by landscape structure. Songs are learned after juveniles disperse from their natal areas, by copying nearby adult males, and typically consist of three to eight discrete types. Territorial calls, by contrast, are learned before dispersal during a short learning phase in summer, likely from parents and neighbors in the natal patch, and consist of just one to three short whistles repeated regularly. This difference in timing means that songs and calls should carry information about movement and social interaction at different life stages.

Between March and June of 2024 and 2025, the researchers surveyed 27 habitat patches spanning the two main strongholds of the species in Spain, the Ebro Valley and the Iberian System. Patch areas ranged from 14 to 1,903 hectares and local male abundance from three to 77 individuals. Working in the pre-dawn darkness, they recorded 188 singing males with directional microphones and high-resolution digital recorders, capturing at least two minutes of song per male, sufficient to document the complete individual repertoire. For calls, they recorded a minimum of three calls per individual, ultimately sampling 74 calling males across 11 populations. When no birds were detected during repeated visits, autonomous recorders were deployed to confirm genuine absence.

The acoustic analysis was meticulous. A single expert scanned all recordings through spectrogram inspection in Raven Pro, delineating each vocalization and classifying it into types based on morphology, temporal patterns, frequency characteristics, and note structure. When classifications were uncertain or types appeared across populations, additional experienced ornithologists reviewed the material, and types were only confirmed when at least two researchers agreed. The final catalog contained 396 distinct song types drawn from 4,208 annotated songs, and 60 call types from 634 annotated calls. These were converted into presence-absence matrices allowing the team to compute repertoire sizes at both individual and population levels, and to quantify acoustic similarity between every pair of males using the Jaccard index.

The results revealed a striking divergence between the two vocalization types. Individual song repertoire size did not depend on population size, but varied significantly between regions, with Ebro Valley males singing larger repertoires than those in the Iberian System. At the population level, however, song repertoire size increased significantly with the number of territories, likely because larger patches host multiple local dialects among neighboring groups of males. Call repertoires, whether measured per individual or per population, showed no relationship with population size, geography, or sampling effort. Songs, in short, behave as flexible cultural traits molded by social environment, while calls remain remarkably conservative and spatially stable.

The spatial analysis sharpened this contrast. Acoustic similarity between males declined steeply with distance for both signal types, but calls were always more similar than songs at every scale examined. Neighboring males within 500 meters shared substantial portions of both repertoires, with mean song similarity of 0.48 and call similarity of 0.60, both far above random expectations. Between populations, similarity collapsed to almost nothing. Fine-scale analysis in 100-meter distance classes uncovered a telling threshold: song similarity declined steadily and leveled off beyond roughly 500 meters, while call similarity remained relatively constant up to a kilometer. Because adults disperse only about 100 to 150 meters, the wider coherence of calls hints that juveniles move at least a kilometer within their natal patches before dispersing, offering a rare behavioral clue about a life stage that has remained almost entirely invisible to researchers.

The most consequential result came from a two-decade natural experiment. The team revisited 50 populations originally monitored between 2004 and 2007, spanning most of the European range, and asked whether historical mean song repertoire size predicted population fate in 2025. A binomial logistic regression delivered a clear answer: populations with larger individual song repertoires had significantly higher persistence probabilities. Extinct populations had averaged 4.9 song types per male, compared with 5.7 in those that survived. Only one extinct population, five percent, had exceeded a mean repertoire size of 6.0, whereas 43 percent of surviving populations did, and not one of the nine populations with means above 6.25 was lost over the following twenty years. This threshold, the authors suggest, may mark the point below which extinction risk rises markedly.

The researchers are careful to note that population persistence depends on many interacting pressures, from wind farm development and grazing regimes to genetic erosion, habitat quality, and extreme weather events. Yet the strength of the acoustic signal is hard to ignore, and it validates, on a far broader geographic scale and a much longer timescale, an idea first proposed in 2008: that a cultural trait can serve as a predictor of population viability. Because vocal repertoire size can be measured non-invasively from field recordings, even with autonomous units, it offers managers a practical, low-cost indicator for tracking population health before declines become irreversible.

Beyond its conservation implications, the study fills a fundamental gap in behavioral ecology. Most research on avian vocal behavior has focused on songs and alarm calls, rarely comparing multiple signal types within the same species. By showing that songs and calls follow partially independent ecological rules, shaped by different learning schedules, dispersal stages, and social contexts, the work demonstrates how much information is layered into a dawn chorus. For a species clinging to fragmented fragments of Spanish steppe, those layers may now determine whether conservationists hear its song for decades to come, or only its echo.

Subject of Research: Acoustic communication, vocal repertoire size, and population viability of the endangered Dupont's lark

Article Title: Singing and Calling Behavior of a Threatened Passerine With Spatially Variable Vocalizations: Individual, Population and Geographic Patterns

Article References: Pérez‐Granados, C., Alonso‐Moya, C. D., Barrero, A., Sáez‐Gómez, P., Bota, G., Lahoz‐Monfort, J. J., Laiolo, P., Méndez, M., Serrano, D., Tella, J. L., Vögeli, M., & Traba, J. (2026). Singing and Calling Behavior of a Threatened Passerine With Spatially Variable Vocalizations: Individual, Population and Geographic Patterns. Ecology and Evolution, 16(9), Article e74380. https://doi.org/10.1002/ece3.74380

Image Credits: AI Generated

DOI: 10.1002/ece3.74380

Keywords: Dupont's lark, birdsong, vocal repertoire, bioacoustics, habitat fragmentation, population viability, conservation, cultural transmission, acoustic similarity, dialects, steppe birds, early-warning signal

The Florida scrub-jay, the only bird species endemic to Florida, has become an icon of the state’s vanishing oak scrub habitats. Decades of habitat loss and fragmentation have left remaining populations isolated in small patches, where inbreeding and lost genetic variation can erode fertility, survival and resilience to disease. Deaner’s project builds on regional recovery efforts that began in the late 1990s through mitigation work led by the Mosaic Company, with early guidance from the late Reed Bowman, a prominent Florida avian biologist. Today, Raoul Boughton, senior manager of ecology and wildlife at the Mosaic Company, leads the recovery effort, with Deaner and Sahas Barve, program director of avian ecology at Archbold Biological Station, serving as co-principal investigators. Their collaboration spans wildlife managers, academic geneticists and field ecologists, reflecting the interdisciplinary scope that modern species recovery demands.

The scale of this translocation sets it apart. Previous scrub-jay relocations typically involved moving small numbers of birds over several years, producing gradual, hard-to-interpret changes. This time, researchers translocated 48 Florida scrub-jays to a new recipient site in one coordinated effort, enough birds to fill the site to its estimated carrying capacity. Every one of the 48 birds hatched in 2025, a deliberate design choice that eliminated age-related competitive advantages and allowed the team to observe how a cohort of young birds establishes itself from a level starting point. The result is essentially a controlled experiment in population establishment, replicated at a landscape scale that no previous scrub-jay study has attempted.

What happened next surprised even the researchers. Florida scrub-jays typically delay breeding, usually not becoming breeders until they are 2 or 3 years old, and younger birds instead remain on their parents’ territories as helpers, feeding nestlings and defending the family group. Across six decades of monitoring at Archbold Biological Station and two decades of data from the local population, fewer than 0.25 percent of recorded nesting attempts involved pairs of one-year-old birds. Yet at the recipient site, just six months after the translocation, four of the 10 newly formed pairs of one-year-old birds attempted to nest, a rate of 40 percent. The team had expected roughly half of the groups to include young birds serving as helpers; instead, most of the translocated jays sought their own breeding territories almost immediately.

That precocious breeding behavior matters far beyond its novelty. Genetic rescue ultimately works only if translocated individuals survive, find mates, reproduce and pass their genetic variation into the recipient population. The nesting attempts signal that the founding birds are not merely persisting but actively claiming territories and pairing up, giving researchers an early window into whether and how genetic integration will occur. While it remains too soon to measure the translocation’s long-term effects, the speed of establishment suggests the young birds detected something unusual about their circumstances, whether the absence of older competitors, the availability of vacant habitat, or some combination of social and ecological cues, and responded by accelerating their life histories.

The scientific machinery behind the project combines two powerful data streams. Genomic sequencing allows the team to examine patterns of genetic variation among source populations, identifying how different lineages have diverged and which combinations of breeding might maximize heterozygosity and minimize inbreeding in the next generation. Meanwhile, long-term field monitoring, the kind of painstaking, bird-by-bird observation that Deaner and her colleagues have honed over decades, provides the demographic reality check: survival rates, reproductive output, territory establishment, dispersal distances and population growth. The team integrates both streams using Vortex, a population viability analysis software that models how genetic, environmental and demographic factors interact to affect a species’ probability of persistence. By running scenarios with and without genetic rescue, the researchers can quantify how much a single large translocation might shift the population’s trajectory decades into the future.

Innovative tracking technology adds another layer of precision. Each translocated jay carries an RFID tag, and the team established feeding stations where a bird must stand on an antenna to access peanuts. Every visit is automatically recorded, giving Deaner a continuous, individual-level log of presence and social feeding behavior. Those visitation patterns do more than confirm survival; they may reveal the subtle early signatures of pair formation, as two birds begin appearing at the same stations at overlapping times. Identifying emerging pairs quickly allows the researchers to target those birds for intensive reproductive monitoring, locating nests, confirming clutch sizes and, eventually, sampling chicks for genetic analysis to confirm which parents contributed which alleles to the next generation.

Deaner’s path to this project runs directly through the species itself. Between earning her undergraduate degree at the University of Delaware and her master’s degree at Georgia Southern University, she spent six years conducting early translocations involving the very same Florida scrub-jay population she studies today. Collecting those field data, she says, and knowing that so many answers lie just beneath the surface of each spreadsheet, is what first inspired her to pursue graduate school. After completing her master’s degree, she returned to the scrub-jay recovery project, where the experience reinforced her conviction that genetic recovery is essential to the population’s long-term persistence. At UCF, she found an academic home that could match her field experience with analytical firepower. She conducts her research in the Conservation Genomics Lab of Eric Hoffman, chair and professor in the UCF Department of Biology, working alongside students tackling parallel conservation questions. Her dissertation weaves together conservation genomics, population ecology, behavioral ecology, spatial analysis and population modeling, an integration she credits to the university’s collaborative and interdisciplinary approach to biology.

The implications of the work extend well beyond a single species. If the scrub-jay translocation demonstrates that a one-time, carrying-capacity introduction of young, genetically diverse individuals can jump-start population recovery, it could reshape how managers design rescue programs for other imperiled species, potentially achieving results faster and with fewer resources than incremental translocations spread over many years. Deaner hopes the research will ultimately help conservationists recover imperiled species more quickly and more efficiently, turning genetics from a diagnostic tool into an active lever for restoration. In September, she will present preliminary findings at the International Conservation Translocation Conference in Edinburgh, Scotland, sharing early results with a global community of translocation practitioners.

For Deaner, the project is also a testament to a philosophy of curiosity-driven science. It is not the taxon that matters, she says, but the questions; as long as the questions are the ones that trigger your curiosity, you are heading in the right direction. With 48 young jays establishing territories, pairing up and attempting nests in habitat where their genes have never flowed before, the questions she has pursued for nearly twenty years are finally being answered in real time, one banded bird and one RFID log entry at a time, in the scrublands of central Florida.

Subject of Research: Conservation genomics of genetic rescue in the Florida scrub-jay

Article Title: UCF researcher uses conservation genomics to advance Florida scrub-jay recovery

Article References: UCF researcher uses conservation genomics to advance Florida scrub-jay recovery. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Florida scrub-jay, conservation genomics, genetic rescue, translocation, population viability, RFID tracking, mate choice, University of Central Florida, Archbold Biological Station, endangered species recovery, population genetics, wildlife conservation