Passive acoustic monitoring (PAM) provides new opportunities for assessing bird abundance and habitat preferences, yet its performance relative to traditional point-count surveys (PCO) remains insufficiently tested, especially for quiet and inconspicuous forest passerines. We compared the vocal activity and habitat associations of the Goldcrest Regulus regulus and Firecrest Regulus ignicapilla in a temperate forest ecosystem using PAM-derived and PCO-based indices. Across 30 monitoring points in the Romincka Forest (Poland), PAM yielded >33,000 recorded songs and revealed strong spatial variation in both species. Vocal activity measures obtained from PAM correlated positively with PCO detections and territories, confirming the reliability of PAM as a complementary abundance indicator. Goldcrest vocal activity showed a strong positive association with the proportion of coniferous trees—especially spruce—and with local tree-species richness, reflecting the species’ affinity for structurally diverse conifer-dominated stands. In contrast, Firecrest abundance was unrelated to forest structure in PAM data, while PCO detections indicated avoidance of pine and lower activity in species-rich stands. No significant relationship with stand age was observed for either species. The weak interspecific correlations in activity parameters highlight their distinct ecological niches despite overlapping ranges. Based on PCO Goldcrests proved to be more abundant, with a territorial ratio of 3:2 compared to Firecrests. Our study demonstrates that PAM effectively captures variation in abundance and habitat selectivity of both Regulus species and provides a scalable, efficient complement to traditional surveys in temperate forest ecosystems.

The Carpathian Mountains have one of the largest remaining primeval and natural forests in the European Union and have been little studied in terms of biogeography. In this paper, we consider the elevational distributions of bird assemblages in the Western Carpathians and the environmental factors that drive them. We used censuses performed by territory mapping methods and explanatory data from 38 study sites (139-year samples) along an elevational gradient from lowland to subalpine zones. We analysed these data matrices with bootstrapped cluster analyses and indirect and direct correspondence analyses (DCA, CCA, CO-CA). Cluster analyses of Euclidean distances from the presence/absence, density, and dominance matrices produced differing numbers of significant clusters (8, 6, 7) corresponding to six, four and five elevational belts. Only three elevational zones—lowland, mountain, and subalpine—were consistent in all classifications. Explanatory variables, i.e. floristics, precipitation, temperature and productivity, had the overall highest rank in explaining the variance in canonical correspondence analysis (CCA) ordinations. Floristics and woody plant species dominance were strong predictors of the elevational pattern of bird assemblages in co-correspondence analyses (CO-CA). Our results support the Clementsian concept of significant and discrete assemblages, not tied to fine habitat types, yet rather defined along wide habitat scales.

The Common Myna (Acridotheres tristis) is a globally recognized invasive alien species with documented ecological and social impacts. This study employed a citizen science approach to investigate the distribution and perceived ecological and economic effects of the Common Myna in Jordan. An online questionnaire yielded 201 valid responses from all 12 governorates, of which only 50.2% of respondents who recognized the species were included in the subsequent data analysis. Reports from 113 localities indicated that the species is concentrated in urbanized areas of northwestern Jordan. Increased sightings since 2019 suggest population growth and continued expansion across human-modified landscapes. Increased occurrences near protected and in agricultural areas raise ecological concerns. Respondents identified competition with native birds as the main impact, while effects on crops and human health (e.g., noise) were perceived as minor. Urban expansion and food waste were viewed as key drivers of the spread. Beyond data collection, the survey also functioned as an awareness tool, highlighting the dual value of citizen science for both monitoring and education. Overall, the study highlights the importance of implementing coordinated management measures that integrate regulation, waste management, and public awareness.

Apodids (Swifts and Swiftlets) are among the under-studied bird species. They are hard to identify, and their breeding habitats are inaccessible, making studying their population estimation and related dynamics challenging. In this study, we aimed to estimate the populations using the capture-mark-recapture (CMR) and nest count methods. Conducted at the Baratang cave complex in the Andaman Islands, our study used stratified sampling to choose 12 study caves based on the breeding population for capture and recapture in all possible caves occupied by Edible-nest Swiftlet (Aerodramus fuciphagus). The use of the Lincoln Index to estimate the populations of the Edible-nest Swiftlet in each cave by analyzing the capture-mark-recapture data and using the program MARK with the Live Recaptures. The Lincoln Index and total population count estimated 486 and 505 birds, respectively, with no significant difference (p > 0.05). The best-fit model indicates that the annual survival rate was consistent throughout the study period (0.97–1.00), and the capture probability was 0.35 ± 0.02. The study evidently showed that using only one method is inadequate for accurately estimating the Edible-nest Swiftlet populations. The CMR method is recommended as an alternative when it is necessary to understand related population dynamics, and the nest and roost count methods are not feasible. The study confirms the effectiveness of the CMR method when used in combination with other traditional methods.

Birds often return to the same locations where they have previously bred successfully or survived the winter, demonstrating site fidelity. This behaviour extends beyond breeding sites to include roosting and feeding areas, with individuals frequently recaptured at the same locations across years. In this study, we investigated the winter site fidelity of Great Tits and analysed how various factors (winter temperature, sex, age, site, date of first capture, and winter season) influence recaptures within and between winters. We monitored individuals roosting in nest boxes at two sites within Bratislava city, western Slovakia. Within-winter site fidelity was observed in 45.89% of birds (N = 146), meaning these individuals were recaptured at least once during the same winter at the same site. Among the tested variables, age and date of first capture in the season significantly influenced within-winter site fidelity. Older birds and those captured earlier in the season were more likely to be recaptured in the same winter. Between-winter site fidelity, defined as birds ringed and later recaptured in a different winter, was observed in 12.92% of 178 Great Tits. Age was a significant factor, with older individuals being more likely to be recaptured in subsequent winters. Furthermore, birds that were recaptured more often during their first winter had a higher likelihood of being recaptured in later winters, suggesting consistent long-term site use.

The Crested Tit (Lophophanes cristatus) is a relatively common species in Finland but is declining likely due to increasing anthropogenic pressures and habitat degradation. Here, we study habitat preferences of Crested Tits in Southwest Finland. We conducted a passive acoustic survey of the species’ presence and absence just prior to breeding in spring 2020 based on 1-week recordings made in 285 forested sites that were about 1 km from each other. We found that Crested Tits prefer a higher amount of pine foliage within a 100-meter radius but not at 400-meter radius. Contrary to our expectation, Crested Tit occurrences showed no preference for mature forests. Additionally, we found that Crested Tits avoid proximity to houses. No habitat preference was evident at the scale of 400-meter radius, probably because a significant proportion of habitat types are not used by the species at this scale. Lastly, despite the overall decline in the Crested Tit population in Finland, we found Crested Tits to be present in 68% of our sites, emphasizing the robustness of passive acoustic surveys as a valuable tool for studying avian habitat preferences and population monitoring. The findings contribute to our understanding of Crested Tit ecology in the face of habitat degradation and declining populations, offering insights for conservation measures in this region.

In many migratory birds, arrival at breeding grounds is sexually asynchronous. This pattern is often explained by the idea that early arrival benefits the sex under stronger sexual selection by improving access to mates through territoriality. However, in species where females arrive first and are non-territorial, this explanation falls short. One alternative is that early-arriving females are simply in better condition. Here we report, for the first time, evidence of migratory protogyny in the Icelandic population of Red-necked Phalaropes (Phalaropus lobatus), a shorebird with reversed sexual dimorphism. We also present the first direct test of the condition-dependent hypothesis in a protogynous species, using arrival data, morphometric measurements, and leukocyte profiles. Although females arrived significantly earlier than males, we found no evidence that early arrival was linked to superior body condition. Leukocyte profiles did not suggest marked sex differences either, although we had insufficient statistical power to test this. Our results point instead to the role of sex-specific migratory strategies and intrasexual competition in shaping arrival timing. With its unique life history, P. lobatus offers a powerful model for studying the evolution of sex-biased migration. We encourage further research integrating fine-scale tracking, reproductive monitoring, and physiological data to better understand ...

Bird hunting, with deep historical and cultural significance, faces sustainability challenges, particularly for migratory species. In Poland, the calibration of annual harvest ceilings (quotas) relative to realized harvest and current abundance is debated. This study: (i) examined the Słupsk Hunting District by comparing district annual quotas (plans) with realized harvest, (ii) examined alignment between nationwide mid-winter (January) goose counts and season-long district harvest totals (Sep–Jan), and (iii) surveyed hunter demographics and preferences. Results showed significant discrepancies, with realized harvest totals well below planned levels (median = 11%). Goose abundance correlated moderately with harvests (r = 0.647, p < 0.0001), though phenological (mid-winter vs season-long) and effort mismatches limit interpretations. Among the hunters surveyed, more than one-third were over 45 years of age (36.2%). Most of these hunters chiefly targeted ducks (ca. 80% of respondents) and, to a lesser extent, geese (ca. 40%). These findings highlight that the maximum set quotas (ceilings) often exceed locally attainable harvest and emphasize the need for standardized monitoring, transparent quota recalibration and adaptive harvest strategies, and policy reforms to align hunting practices with ecological realities (current abundance and seasonal availability under observed effort), ensuring viable and sustainable wildlife management in Poland.

Partial migrants have populations consisting of both migratory and resident individuals. These migrants and residents experience unequal ecological conditions during winter and the underlying factors driving their decision to stay on their breeding grounds or to migrate remain debated—both from the viewpoint of populations and individuals. Here, we studied partial migration in a small raptor, the Eurasian Sparrowhawk (Accipiter nisus), from two different but interconnected perspectives: 1) explaining the patterns and variation in the ratio of migrants to residents (migratoriness) at the population level and 2) revealing how age and sex may affect the individual decision to be migratory or resident. We used citizen observation data over four decades to explore the temporal and spatial variation in the age and sex ratio of wintering resident sparrowhawks in Sweden. We found that the migratoriness unexpectedly increased with higher annual temperatures and showed long-term trend across the study period. Also, this migrant-to-resident ratio increased with smaller winter prey abundance. The average winter sex ratio was male-biased and became increasingly so over the years. We suggest that residency benefits territory-establishing males as early presence gives a competitive advantage in obtaining high-quality territories. Moreover, the distribution of overwintering individuals (regardless of sex) moved gradually northwards as the winter progressed, suggesting that smaller-scale migration occurs among the resident fraction of the population. These results provide suggestions for the underlying drivers and regulation of partial migration.

The newly released textbook, Ecology and Conservation of Mountain Birds (edited by Chamberlain, Lehikoinen & Martin), provides a comprehensive review of the latest knowledge in alpine ornithology. It summarizes the combined knowledge of over 50 subject experts and serves as an excellent reference guide for professionals and students. Here, the layout and contents of the book are reviewed and an unbiased general assesment of the contents are provided. As the global environment continues to see unprecedented changes, this work should serve as a groundbreaking benchmark describing the state of our mountain birds.