Diego Rubolini

Point counts are a fundamental tool in avian ecology, yet the consequences of changing count duration remain poorly quantified, particularly across seasons and spatial scales. Using 660 time‐partitioned point‐count visits at 220 points in six Italian cities during the breeding and wintering seasons, we assessed the effect of reducing count duration from 10 to 5 min on per‐visit ( α ) and city‐wide ( γ ) species‐richness and on abundance, and tested whether losses were predicted by species traits. Five‐minute counts captured 81% of point‐level richness during breeding and 77% in winter, and missed up to 20% of the species recorded city‐wide by 10‐min counts in winter; winter losses were concentrated in migratory and small‐bodied species, whereas abundance retention (c. 81%) did not differ between seasons. Five‐minute counts may therefore suffice for abundance indices of common species, but not for describing community composition.

Each year, migratory birds move thousands of kilometres across international borders to track optimal environmental conditions. How tightly annual-cycle events are linked and how much flexibility exists in migration schedules will determine how vulnerable migratory birds are to environmental change. Using a global tracking database, we reconstructed full annual-cycle schedules of 2,324 individuals from 83 species. We found strong temporal links during autumn and spring migrations: departure from the breeding grounds predicted arrival at the non-breeding grounds and vice versa. During both migration periods, late-departing individuals shortened migration duration, but still arrived later than early-departing individuals. By contrast, arrival at and departure from the non-breeding grounds were not correlated, suggesting a temporal reset that buffered earlier delays. Despite resetting during the non-breeding period, migratory schedules remain globally interconnected, such that disruptions in one season can propagate to subsequent stages of the annual cycle, with consequences for migratory species and the ecosystem functions they support.

Countries have committed to expanding the marine protected area (MPA) network to 30% of the world's ocean by 2030, more than tripling current coverage, and focusing on areas important for biodiversity. For such expansion to translate into effective conservation of marine biodiversity, it must rely on the best available knowledge. Here, we analyze tracking data on > 13,000 individuals (44 species, eight families) to map the distribution of highly mobile seabirds in the Atlantic Ocean and adjacent seas throughout the year. We identify regions important year‐round or seasonally. The High Seas are as important as national waters for highly mobile seabirds but are even less protected. Current Atlantic MPAs hold < 14% of tracked species density, but their expansion to 30% of the ocean could protect up to two thirds. We share this new knowledge layer to support national and international efforts and policies to strategically expand the Atlantic MPA network.

Parental decisions on breeding, such as brood size and timing of reproduction, influence the early‐life environment of the offspring, exposing them to variable levels of stressors, which in turn may affect their fitness. In this context, telomeres, conserved DNA sequences at chromosome ends that shorten with age and stress exposure, are relevant because telomere length may predict survival and act as a biomarker reflecting inherited and stress‐induced variation in somatic state, thereby linking early‐life conditions to future fitness. However, studies examining whether early‐life conditions are associated with telomere length and whether telomere length predicts subsequent survival remain limited and provide contrasting results. We examined the effects of parental decisions (brood size and hatching date), as well as parental age and quality (i.e., outermost tail feather length), on telomere length of male barn swallow ( Hirundo rustica ) nestlings that recruited in their natal site as breeding adults in the following years. We also investigated whether nestling telomere length predicted long‐term survival. Telomeres were shorter with increasing brood size, suggesting a detrimental effect of a stressful developmental environment on telomere length. In addition, nestlings raised by older fathers (but not mothers) had shorter telomeres, indicating a possible father aging effect on telomere length. Furthermore, individuals with longer telomeres at the nestling stage showed a higher likelihood of surviving beyond the first year of life. Overall, our results suggest that early‐life telomere length may link parental decisions and age to fitness prospects and may thus be a target of selection even in short‐lived species.

Epigenetic clocks are powerful tools for estimating both chronological and biological age, enabling the integration of age information into population monitoring, demographic modelling, and research on the ecophysiology and evolution of ageing. Most epigenetic clocks so far have been developed for mammals: here, we present the Bird Epigenetic Ageing Clock (BEAC) for estimating chronological age in avian species. BEAC was established based on genome-wide enzymatic methylation sequencing data of known-age king penguins (Aptenodytes patagonicus), and validated in nine other bird species. The BEAC collects age-informative signals into a bisulfite amplicon sequencing panel of 24 primer pairs, providing a highly accurate and cost-effective alternative to sequencing-intensive approaches. It achieved strong predictive performance in independent king penguin training (R2=0.88; MAE=1.7 years, n=78) and testing data (R2=0.79; MAE=2.3 years, n=41), with negligible batch effects, high longitudinal consistency, and resilience to reduced sample size or missing loci. Importantly, cross-species validation across 180 samples showed that BEAC reliably captures age-associated methylation signals in nine additional bird species across seven clades, demonstrating that a single set of loci can be predictive of ageing across multiple different bird species. BEAC offers a flexible, empirically validated tool and a transferable framework for developing epigenetic clocks in avian species, providing a highly valuable resource for eco-evolutionary studies of ageing in wild species.

Identifying molecular mechanisms linked to variation in lifespan, reproductive output and sexually selected traits is key to understanding life‐history evolution in wild populations. Telomere length (TL) and attrition (ΔTL) have been proposed as biomarkers of somatic state and maintenance (survival). Yet evidence linking telomeres to lifetime fitness and ornament expression remains limited. We quantified age‐related variation in TL and annual ΔTL between the year of recruitment (1‐year‐old) and death, as well as tested whether TL at recruitment predicts realized lifespan and lifetime reproductive success in a short‐lived migratory passerine, the barn swallow ( Hirundo rustica ). We also examined associations between TL/ΔTL and two sexual ornaments (outermost tail feathers length and ventral plumage colouration). TL constantly declined with age, and longer TL as yearling was linked to increased lifespan and higher number of fledglings during the entire life, indicating that TL captures considerable variation in individual quality. Moreover, longer tail feathers and a larger increase in tail length between consecutive years were associated, respectively, with shorter TL and faster ΔTL among females. Additionally, plumage darkening between consecutive years was associated with reduced ΔTL in both sexes, indicating that telomeres covary with secondary sexual traits in a sex‐ and trait‐specific manner and may be involved in sexual selection processes. Overall, even in a species with high annual mortality, TL positively predicted major fitness components, supporting TL as a biomarker of individual quality and suggesting that longer telomeres at the onset of adulthood may be favoured by natural selection in wild populations.

The reference genome of the Eurasian Woodcock ( Scolopax rusticola) is an important resource to investigate population structure across the wide breeding range of this iconic game species and the conservation status of specific management units, such as the isolated Macaronesian populations. The genome sequence was assembled into 45 contiguous chromosomal pseudomolecules and 2 sex chromosomes (W and Z). This chromosome-level assembly encompasses 1.2 Gb, composed of 1,613 contigs and 935 scaffolds, with contig and scaffold N50 values of 5.9 Mb and 34.2 Mb, respectively.