Journal of Avian Biology最新文献

{"title":"Female biased offspring sex ratios of eastern wild turkeys across the southeastern United States","authors":"Erin E. Ulrey,&nbsp;Paige E. Goodman,&nbsp;Sara A. Watkins,&nbsp;Nicholas W. Bakner,&nbsp;Patrick H. Wightman,&nbsp;Chad M. Argabright,&nbsp;Philip Lavretsky,&nbsp;John C. Kilgo,&nbsp;Helen M. Bothwell,&nbsp;Bret A. Collier,&nbsp;Michael J. Chamberlain","doi":"10.1002/jav.03515","DOIUrl":"https://doi.org/10.1002/jav.03515","url":null,"abstract":"<p>Prevailing theory suggests that sex ratios of offspring at birth should not differ from parity if costs of producing offspring of both sexes are similar. However, offspring sex ratios may deviate from parity when there is sex specific variation in fitness returns. We assessed offspring sex ratios of eastern wild turkeys (<i>Meleagris gallopavo silvestris</i>) across the southeastern United States by molecular determination of sex from eggshell membranes of hatched clutches. Our objective was to evaluate whether offspring sex ratios differed from parity and to examine potential drivers of variation in offspring sex ratios across and within our study sites. We sexed 724 offspring from 83 nests using molecular markers and identified 278 males and 446 females, with a sex ratio of 38% male. We found that offspring sex ratios were biased towards females on three hunted study sites but did not differ from parity at our remaining non-hunted site. Specifically, on sites with spring hunting, where male mortality was increased due to harvest, the probability of producing male offspring was 47% lower than on our non-hunted site. Our findings suggest that female wild turkeys may adaptively adjust the sex ratio of their offspring based on predictable, sex specific mortality, favoring the sex with higher survival, thereby enhancing their lifetime fitness. Our results provide insights into reproductive strategies of wild turkeys and the influence of hunting on sex ratios in Galliform offspring.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 5","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03515","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impacts of sleep disturbance on birds: a review of the knowledge gaps","authors":"Kamya Patel,&nbsp;Juliane Gaviraghi Mussoi,&nbsp;Margaret C. Stanley,&nbsp;Kristal E. Cain","doi":"10.1002/jav.03454","DOIUrl":"https://doi.org/10.1002/jav.03454","url":null,"abstract":"<p>Sleep is an evolutionarily conserved behaviour critical to animal function. While the exact functions of sleep are still unclear, the ubiquity of sleep behaviour and its potential high costs (e.g. reduction in foraging time, increased vulnerability to predators) suggest sleep serves a critical role for animals. Animals that share environments with humans, such as urban birds, face numerous anthropogenic stimuli that are likely to fragment or alter their sleep. In this literature review, we synthesise the current research available on sleep disturbance in birds and provide suggestions for future research to address key gaps. Our analysis revealed that knowledge on how sleep disturbance affects birds is currently fragmented, is often inferred rather than explicitly measured, and fails to connect causal mechanisms to ecologically relevant outcomes. To address these critical knowledge gaps, we suggest that future research on sleep should: 1) incorporate both the effect of stimuli on sleep and the resulting consequences of this sleep loss on the behaviour and fitness of the study species; 2) broaden to include contexts other than migration and seasonal change; 3) include juvenile birds that are still in the development phase; and 4) explore a greater range of the potential functional consequences of disrupted sleep. Understanding the fitness-related consequences of sleep disturbance from anthropogenic stimuli will provide critical insights into the impact of these stimuli on birds, and how to mitigate the impacts of sleep disturbance in urban environments.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 5","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03454","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sequencing method matters: differential performance of DNA methylation data acquisition in epigenetic clock calibration","authors":"Livia Gerber,&nbsp;Aaron W. Schrey,&nbsp;Susan C. Anderson,&nbsp;Erena Jain,&nbsp;Andrea L. Liebl","doi":"10.1002/jav.03498","DOIUrl":"https://doi.org/10.1002/jav.03498","url":null,"abstract":"<p>Age is an important trait, influencing an individual's physiology, behavior, and survival probability. Unfortunately, the ages of wild animals are often unknown, impeding behavioral and ecological studies requiring life history information and impacting conservation efforts for threatened species. Epigenetic clocks offer a solution by generating accurate age estimates based on DNA methylation at particular CpG sites, which changes in a predictable manner over lifespan. The CpG sites correlating with age vary across species, requiring species-specific epigenetic clock calibration using DNA methylation measured at CpG sites across the genome. Here, we compared the efficacy of two DNA methylation sequencing methods, whole genome enzymatic methyl sequencing (WGEM-seq) and epiRADseq, in calibrating epigenetic clocks for chestnut-crowned babbler <i>Pomatostomus ruficeps</i> nestlings (n = 56, aged 0–19 days). We found that epigenetic clocks using WGEM-seq data outperformed clocks using epiRADseq data (MAE = 1.6 versus MAE = 5.9; r = 0.95 versus r = 0.41 for 10-fold cross-validation). Notably, WGEM-seq achieved superior performance despite utilizing fewer loci in the input data than epiRADseq, indicating that the lower resolution of epiRADseq does not allow for accurate clock calibration. Using WGEM-seq data collected throughout a small fraction of the lifespan of chestnut-crowned babblers, we successfully calibrated a highly accurate epigenetic clock. These results open promising avenues for investigating the impact of early life environments and developmental stressors on aging. The insights gained from such studies can improve conservation and management strategies while deepening our understanding of avian life history strategies, ecology, and behavior.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 5","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03498","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperatures inside little penguin Eudyptula minor artificial nest habitats exceed upper thermal limits in a range edge population","authors":"Erin K. Clitheroe,&nbsp;Belinda L. Cannell,&nbsp;Kathy L. Murray,&nbsp;Joseph B. Fontaine","doi":"10.1002/jav.03382","DOIUrl":"https://doi.org/10.1002/jav.03382","url":null,"abstract":"<p>Rising global temperatures will have profound impacts on species and ecosystem functioning. Species existing near their thermal thresholds will be particularly vulnerable to these changes, and those species that rely on, or preferentially use, artificial structures may face pronounced effects. Gaining insights into the anticipated climate changes, both present and future, is crucial for informing conservation practices and the utilisation of artificial structures in conservation efforts. Using three years of data, we quantified and compared temperature of artificial nest boxes installed between 1986 and 2006 and natural nest burrows of a fringing population of little penguins existing at the northwestern limit of their range. Nest boxes were ineffective at replicating conditions of natural nests, exhibiting consistently higher daily maximum temperature (~ 2˚C) and exceeded upper thermoneutral limits for longer than natural nests. Fine scale biotic and abiotic nest characteristics influenced maximum nest temperature and time exposed to temperatures ≥ 35˚C. Simulated temperature increase of 2˚C predicted an increase in the number of days exceeding thermally stressful conditions (≥ 35°C) by up to 49%. Such increases will expose penguins to potentially fatal thermal conditions, particularly during the late breeding and moulting phases of their annual cycle. This study revealed that current and future thermal environments of little penguin terrestrial habitat on Penguin Island can exceed physiological limits for this species. Intervention to improve artificial nests and better quantify consequences is urgently needed given recent estimates of a declining population and increasing risk of local extinction.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144905456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LiDAR-derived high resolution vegetation structure and selection patterns of the common nightingale Luscinia megarhynchos in riparian habitats","authors":"Jean-Nicolas Pradervand,&nbsp;Florian Zellweger,&nbsp;Jérémy Gremion,&nbsp;Aristide Parisod,&nbsp;Bertrand Posse,&nbsp;Emmanuel Revaz,&nbsp;Alain Jacot","doi":"10.1002/jav.03350","DOIUrl":"https://doi.org/10.1002/jav.03350","url":null,"abstract":"<p>Human-induced alterations in natural water flow have seriously impaired the integrity of riverine ecosystems. Nonetheless, even in human-altered riverine and adjacent terrestrial habitats, there is considerable potential for the protection of rare species if management practices prioritize biodiversity conservation. However, the management of such areas often presents complex challenges. On the one hand, efforts to mitigate natural hazards frequently overshadow biodiversity conservation objectives. On the other hand, high-resolution maps of forest structures are often lacking but could be very useful for spatial prioritization of conservation efforts, especially as vegetation structure can be directly managed through local restoration activities. Here, we used an airborne LiDAR-derived vegetation structure along an 80 km stretch of the Rhône River (Valais, Switzerland) to assess the habitat characteristics that best explain the presence of a flagship species, the common nightingale <i>Luscinia megarhynchos</i>, a species that historically thrived along this river system but has experienced a drastic population decline over the past decades. Nightingales showed a preference for dense vegetation in the lower strata above ground (3–6 m), as opposed to an open and sparsely vegetated ground level (0–1 m). The preferred habitats were predominantly located within forested regions, as indicated by a preference for taller canopies. These findings align surprisingly well with prior field research on the species, demonstrating the capability of high-resolution LiDAR to upscale locally derived habitat preferences across very large areas. Based on LiDAR outputs, we proposed management recommendations for the whole river. Such spatially detailed information furthers our understanding of local habitat preferences of endangered species, thus facilitating the formulation of conservation recommendations at the scale of entire populations.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144905399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New insights on the effects of human-induced environmental change on avian reproduction","authors":"Judith Morales,&nbsp;Elisa P. Badás,&nbsp;Juan Diego Ibáñez-Álamo","doi":"10.1002/jav.03558","DOIUrl":"https://doi.org/10.1002/jav.03558","url":null,"abstract":"&lt;p&gt;Human-induced global change currently represents the greatest threat to global biodiversity (IPPC &lt;span&gt;2023&lt;/span&gt;, Keck et al. &lt;span&gt;2025&lt;/span&gt;). In this context, ever since formal efforts to connect behavioural ecology to conservation began at the end of the 20th century, avian research has provided crucial evidence on how anthropogenic impacts modify animal behaviour (reviews by Gil and Brumm &lt;span&gt;2013&lt;/span&gt;, Murgui and Hedblom &lt;span&gt;2017&lt;/span&gt;, Matuoka et al. &lt;span&gt;2020&lt;/span&gt;). Still, we need a clearer understanding of behavioural responses to such perturbations, their mechanisms and adaptive value to improve predictions of how human-driven global change will affect species and biodiversity.&lt;/p&gt;&lt;p&gt;The goal of this special issue was to provide an updated overview of how human-induced environmental pressures specifically affect avian reproductive behaviour, in order to identify key challenges and potential future directions in this field. The thematic issue features eleven papers: nine field-based studies (one of them based on open-access databases), which span a diverse range of ecological contexts, reproductive traits and species, along with a mini-review and a viewpoint article. In field-based studies, Passerines are the most represented taxonomic group, although one work focusses on a shorebird and another one on a bird of prey. In addition, the article based on open data sources includes almost 300 migratory bird species.&lt;/p&gt;&lt;p&gt;The work of Wheeler and colleagues (&lt;span&gt;2025&lt;/span&gt;) investigated a wild zebra finch &lt;i&gt;Taeniopygia castanotis&lt;/i&gt; population nesting in New South Wales (Australia). The authors found that parents reduced their hourly rate of parental visits to the nest by 0.91% following each increase of 1°C in daytime temperature. This interesting finding offers a proximate behavioural mechanism for coping with increasing temperatures, which can help to explain body size declines observed in other bird species in response to climate change.&lt;/p&gt;&lt;p&gt;Four studies in this special issue explored direct human disturbances, urbanization and landscape alterations as primary drivers of environmental change, and these were commonly linked to detrimental effects on avian reproductive traits. The long-term study on a population of great tits &lt;i&gt;Parus major&lt;/i&gt; breeding in the Netherlands, reported that non-motorized recreational activities such as hiking, biking, pet walking or horseback were associated with reduced reproductive success (i.e. smaller clutch size and reduced nestling body size), the relationship being independent of habitat quality (Urhan et al. &lt;span&gt;2025&lt;/span&gt;). Similarly, in a four-year study, Zhang and colleagues (&lt;span&gt;2025&lt;/span&gt;) showed that Chinese blackbirds &lt;i&gt;Turdus mandarinus&lt;/i&gt; experienced constrained extra-pair paternity (EPP) in highly urbanized cities of southern China, while low EPP was in turn negatively associated with fitness-related traits. In addition, Lane and colleagues (&lt;span&gt;202&lt;/span&gt;) pr","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03558","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144881273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Startling ravens Corvus corax at foraging: differences in anti-predator behaviour can be explained by age rather than personality","authors":"Janina Anna Elisabeth Weißenborn,&nbsp;Petra Sumasgutner,&nbsp;Vedrana Šlipogor,&nbsp;Thomas Bugnyar","doi":"10.1002/jav.03437","DOIUrl":"https://doi.org/10.1002/jav.03437","url":null,"abstract":"<p>When individuals of the same population do not respond uniformly to the same situation, they might experience divergent fitness outcomes, such as different survival rates when facing danger. When these behavioural differences between individuals are consistent across time and contexts, they are referred to as ‘animal personality'. We here explored the response to a risky situation as a potential personality trait in free-ranging common ravens <i>Corvus corax</i>. We experimentally tested the repeatability of behavioural variables along the boldness–shyness axis of 12 individually marked ravens belonging to a large non-breeder population in the northern Alps. We played different audio cues of natural (i.e. calls of birds of prey) and human-induced (i.e. gunshots) threats during a predictable feeding situation and scored startle reactions of individual ravens. Results revealed age-specific differences in behavioural responses, but no consistency across time. Young ravens had shorter latencies to feed after our playback stimuli and all ravens reacted with more anti-predator behaviour towards birds of prey calls than gunshots. The missing affirmation of repeatability along the boldness–shyness axis is partly in line with previous findings on the exploration axis in captive ravens, and fits with the reports of high behavioural flexibility in this species. Nevertheless, it is conceivable that our present methodology for assessing boldness–shyness does not fully align with the situational strength and relevance required for foraging ravens, and/or that consistent inter-individual differences become pronounced at specific life stages (i.e. during breeding).</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03437","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144869766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perceived eggshell luminance does not predict rejection of experimental egg models in eastern bluebirds","authors":"Javeria Sirhandi,&nbsp;Raeshia M. Walker,&nbsp;Mark T. Stanback,&nbsp;Mark E. Hauber,&nbsp;Daniel Hanley","doi":"10.1002/jav.03462","DOIUrl":"https://doi.org/10.1002/jav.03462","url":null,"abstract":"<p>Obligate avian brood parasites lay their eggs in other bird species' nests, leaving these hosts to rear the parasitic young. To eliminate or reduce the costs of parasitism, many hosts have evolved the ability to recognize and reject parasitic eggs, and most use eggshell color for recognition; however, color discrimination should be more challenging in the low-light conditions facing cavity-nesting hosts. Therefore, we hypothesized that instead of color, cavity-nesting birds could rely on perceived differences in brightness (i.e. luminance) and on light levels in their nests for egg recognition. Specifically, we expected that rejection rates would be higher when foreign eggs are lighter or darker than the hosts' own eggs or when nest light levels are higher. To investigate this hypothesis, we experimentally altered the luminance of 413 similarly colored (blue) experimental model eggs and added these experimental eggs to the nests of cavity-nesting eastern bluebirds <i>Sialia sialis</i> that typically lay immaculate blue eggs. Contrary to our expectations, neither the perceived luminance of the eggs nor the amount of light in the nest cavity predicted host responses. Therefore, it is unlikely that bluebirds base their antiparasitic decisions on perceived differences in eggshell luminance. Our work provides a foundation for future studies that can inform us about how cavity-nesting birds perceive salient visual stimuli in the dim light conditions of their nests.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03462","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144832753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature drives inter-annual variation in badger Meles meles predation of lapwing Vanellus vanellus on Scottish hill-edge farmland","authors":"Bryony A. Tolhurst,&nbsp;Max A. Wright,&nbsp;David M. B. Parish,&nbsp;Marlies K. Nicolai,&nbsp;Nicholas J. Aebischer,&nbsp;A. Louise de Raad","doi":"10.1002/jav.03436","DOIUrl":"https://doi.org/10.1002/jav.03436","url":null,"abstract":"<p>Wading birds have declined globally, with particularly pronounced declines in western Europe. Multiple species are now on the IUCN Red List, with northern lapwing <i>Vanellus vanellus</i> near-threatened and declining. Historically, habitat degradation, including that from wetland drainage and agricultural intensification, has contributed to population declines. More recently, declines have been attributed to poor breeding success due to unsustainably high rates of predation on eggs and chicks by avian and mammalian predators. In the UK, the red fox <i>Vulpes vulpes</i> is a major mammalian predator of waders. However, the Eurasian badger <i>Meles meles</i> has increased in range and abundance, and can occur at high densities, with potential for acute localised predation impacts on vulnerable wader populations. Factors affecting rates of badger predation on wader nests remain unexplored. We investigated what these factors might be, analysing data from six years of lapwing nest monitoring at a breeding site in northeast Scotland. A negative impact of temperature was detected, where the overall probability of badger predation was above 0.1 when the mean daily temperature was below 4°C during the preceding 7 days, dropping close to zero when above 10°C. Badger predation on lapwing clutches also increased with earthworm availability, and inter-annual effects were observed matching variations in temperature, whereby intense badger predation in 2021 coincided with unseasonably cold temperatures and low lapwing breeding productivity. This highlights the potential for weather forecasting to be used to deploy pre-emptive non-lethal management strategies to mitigate badger predation impacts on lapwing nests.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03436","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144725645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nest mass in forest tits increases with elevation and decreasing body mass, promoting reproductive success","authors":"Clara Wild,&nbsp;Roland Brandl,&nbsp;Orsi Decker,&nbsp;Sophia Hochrein,&nbsp;Andrea Ingrosso,&nbsp;Soumen Mallick,&nbsp;Oliver Mitesser,&nbsp;Julia Rothacher,&nbsp;Simon Thorn,&nbsp;Jörg Müller","doi":"10.1002/jav.03407","DOIUrl":"https://doi.org/10.1002/jav.03407","url":null,"abstract":"<p>Based on the concept of the extended phenotype, bird nest characteristics can serve as indicators for adaptations to changing environmental conditions. We examined how the nest mass of three cavity-nesting tit species Paridae varied across 22 mixed forests in Germany in response to elevation, canopy openness, and species body mass. We predicted that nest mass should increase with elevation and canopy openness, due to thermoregulation being more demanding in colder or warmer climatic conditions, and decrease with body mass, as larger species have greater thermoregulatory capabilities. To test these predictions and to assess the consequences of nest mass variation for reproductive success, we recorded nest mass, clutch size, and pre-fledging brood size in 576 standardized nest boxes. Nest boxes were installed along an elevational gradient of approximately 1000 m a.s.l., either in forest gaps with fluctuating microclimatic conditions or in closed forests with buffered microclimates. We found that nest mass increased by ~ 60% along the elevational gradient, but the effect of canopy openness on nest mass was not significant, while nest mass decreased along the ranked species from the smallest <i>Periparus ater</i> to the medium-sized <i>Cyanistes caeruleus</i> and the largest <i>Parus major</i>. Structural equation modeling revealed that heavier nests were associated with larger clutch sizes, which in turn resulted in larger pre-fledging brood sizes. Altogether, our results suggest that forest tits adjust nest construction in response to macroclimatic conditions, thereby compensating for the thermoregulatory challenges posed at higher elevations and their small body size. This strategy may be critical for maintaining reproductive success in changing environments.</p>","PeriodicalId":15278,"journal":{"name":"Journal of Avian Biology","volume":"2025 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jav.03407","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}