Birds, Volume 7, Issue 3 (September 2026) – 9 articles

The effects of urbanization on woodland insectivorous mixed-species flocks have been little studied, and no seasonal studies have been conducted. This study aimed to describe the structure and seasonal dynamics of insectivorous mixed flocks in urban green areas of Buenos Aires City, Argentina. A total of 82 visits were conducted from April 2025 to March 2026. The potential effects of temperature, precipitation, humidity, and Julian day on flock occurrence were analyzed. The most frequent and abundant bird species in flocks were the White-crested Tyrannulet (Serpophaga subcristata), the Greyish Baywing (Agelaioides badius), the Masked Gnatcatcher (Polioptila dumicola), and the Tropical Parula (Setophaga pitiayumi). Serpophaga subcristata, Polioptila dumicola, and Setophaga pitiayumi tended to occur together in flocks. Flocks were observed in both native and exotic tree species. Flock occurrence was significantly associated with Julian day and peaked in autumn and during the early winter, coinciding with the non-breeding season. These results align with other studies conducted in subtropical and temperate regions. The significant relationship between flock occurrence and Julian day during the non-breeding season suggests that mixed flocking behavior helps individuals and pairs of different bird species by likely improving access to food and reducing predation risk as they move outside their breeding territories. A better understanding of the effects of urbanization on mixed flocks would be gained by comparing the spatial and temporal dynamics of flocking behavior in insectivorous birds in urban green areas with those in the region’s native woodlands. Full article

To feed a growing population, humanity will need to see an increased global agricultural output in crop production. One key strategy for achieving this goal is to reduce herbivory by insect pests, which is one of the leading causes of crop loss. Although there have been many strategies for combating insect herbivores, biological control may be the most sustainable in the long term. Birds in particular are potentially powerful biocontrol agents, but how avian predation varies within individual agricultural settings remains largely unknown. Here, we analyzed temporal and spatial variations in putative avian predation potential on insect pests in a small-scale agricultural setting. Our results show that the spatial distribution of predation potential is nearly uniform across a small field, indicating that birds with their vagility may be particularly well suited for applying constant, uniform coverage, at least across smaller landscapes. We also found that predation potential by birds varied significantly between seasons, with the fall showing the highest rate of predation. We discuss the applications of our findings for further studies investigating the biocontrol potential of natural bird populations and for leveraging such avian predation to help improve food production systems. Full article

Strelitzia reginae (Bird of Paradise) is a South African ornamental plant widely cultivated in tropical and subtropical regions. While naturalized populations have been reported outside its native range, no such cases have been documented for Australia. Drawing on the first known occurrence of a bird-dispersed S. reginae growing epiphytically in a Moreton Bay fig (Ficus macrophylla) in Manly, New South Wales, this paper examines the nature of birds pollinating and dispersing the plant in an alien ecological setting. Crowd-sourced data from social media and citizen science platforms identified 14 bird species visiting S. reginae flowers, with various honeyeaters acting as effective pollinators. Seven bird species were observed feeding on or transporting seeds, suggesting viable mechanisms of dispersal. The study highlights the ecological significance of spontaneous establishment, the role of native birds in facilitating reproduction and dispersal, and the value of leveraging citizen-sourced observations to detect emerging naturalized species. Full article

We compiled records of Sturnus vulgaris (European Starling) in Brazil over the ten years following its first documented occurrence in the country. The dataset included field campaigns and summarized data from citizen science platforms, field data, and reports from researchers and birdwatchers. A total of 2618 abundance records were compiled across 219 occurrences, with only five additional records distributed across the states of São Paulo, Rio de Janeiro, and Minas Gerais, while all others 97.7% came from Rio Grande do Sul state, the southern border of Brazil. In just one decade, the species has expanded across a considerable portion of the Brazilian Pampa, with a mean expansion rate ranging between 19.2 and 25.5 km²/year, with higher abundance along the border with Uruguay. We identified 55 nesting sites, most of which were located in cavities previously excavated by woodpeckers (Picidae), primarily in Eucalyptus trees. Breeding begins in September, peaks between October and November, and extends until the end of December. The data from this study indicates a high degree of behavioral plasticity in the species, facilitating its rapid adaptation and expansion within the Pampa biome. Full article

This study evaluated social media platforms as complementary tools for monitoring threatened and rare bird species in Morocco from 2015 to 2025. Records were extracted from groups, pages, videos, photographs, and ornithological publications based on Facebook, Instagram, TikTok, X, LinkedIn, Telegram platforms. Multi-language and validation criteria were used to standardize records, and then data were analyzed and mapped to assess spatio-temporal dynamics, habitat preferences, and threatening factors. Results revealed significant interspecific differences (p < 0.001), with dominance of Streptopelia turtur arenicola (250 ± 48.35 records), followed by Geronticus eremita and Chersophilus duponti (222.15 ± 26.58 and 222 ± 59.31 records), Acrocephalus paludicola, and Chlamydotis undulata. Adults dominated records (851.54 ± 364.70 records), while eggs and chicks were weakly recorded. Records were mostly photographs and were from Facebook. Digital records were higher in March and April. Spatial records highlighted ecological specialization, G. eremita in Souss Massa and C. undulata in southeastern desert ecosystems. Results showed associations with steppes, riparian, agricultural, and semi-desert mosaics depending on recorded species. Predation (50 ± 3.54 records) and hunting (49 ± 13.44 records) were the main affecting factors, particularly in S. t. turtur (22.22% and 52.38% of records) and C. undulata (31.25% and 62.5%). The identified habitats and threats provide actionable indicators for prioritizing protection, monitoring, and targeted mitigation measures. These findings show that social media can support passive citizen-science and contribute to conservation planning and large-scale ecological monitoring of threatened avifauna. However, future research needs to combine field and digital investigations to reduce biases and present a more comprehensive picture of threatened birds. Full article

The Oriental Magpie Pica serica invaded Hokkaido, Japan, in the 1980s, but little is known about its current population status or potential for further range expansion. Here, we compile records on the distribution of magpies from 2012 to 2016 and estimate potential suitable habitats. Field surveys and citizen science reports revealed that breeding and individual birds occurred in 28 municipalities located in western Hokkaido. Although dozens or more birds have become established in three of these municipalities on the Pacific coast, populations in the other 25 appear not self-sustaining. Suitable habitats for magpies were almost exclusively limited to urban residential areas, presumably due to the availability of anthropogenic food resources. While these apparently suitable habitats occur throughout Hokkaido Island, no sightings have been recorded in eastern Hokkaido, suggesting that magpies have not crossed the forest area that runs north–south through the central part of the island. Suitable habitats, estimated based on the habitat selection by the largest population in Tomakomai, are concentrated near the centers of each municipality, separated by agricultural land, which may have slowed down the range expansion of the magpie through the Allee effect. The island-like fragmentation of suitable habitats is advantageous for comparative studies of magpie populations, food resources, predators, and competitors. Furthermore, the magpie has a distinctive black-and-white coloration and a unique, loud call, making it well-suited for citizen science surveys. Continuous monitoring of Hokkaido’s magpie population by experts and citizens will provide excellent opportunities to ask ecological questions involving bird distributions and the establishment of invasive species. Full article

Diet diversity of owls has traditionally been studied using prey taxonomic composition, but species identities alone do not necessarily capture ecological roles, energetic dominance, or evolutionary breadth of prey. Here we quantified diversity across taxonomic, functional, and phylogenetic dimensions of prey of nine European owl species: Aegolius funereus, Asio otus, Athene noctua, Bubo bubo, Glaucidium passerinum, Otus scops, Strix uralensis, Strix aluco, and Tyto alba. Using a unified Hill-number framework we estimated richness- and evenness-sensitive diversity and evaluated prey assemblage structures using standardized effect sizes from richness-controlled null models. Prey diversity varied strikingly among owls. Diet strongly relied on a limited set of functionally and phylogenetically similar prey. Bubo bubo showed high richness but low evenness, Otus scops specialization, Glaucidium passerinum high evenness, and Athene noctua high phylogenetic breadth. Large differences in taxonomic richness were frequently decoupled from functional or evolutionary breadth, for example in Bubo bubo and Athene noctua. Structural analyses revealed phylogenetic overdispersion in Athene noctua and Otus scops, clustering in Glaucidium passerinum, and extreme functional clustering in Tyto alba and Asio otus. Together, these results show that owl diets are structured along multiple, partially independent axes, best revealed by combining Hill-number profiles with null-model analyses. Full article

Tit species (Paridae) are an important part of urban settlements during winter. We counted wintering tit species from 31 urban settlements along a 920 km latitudinal gradient in Finland during four winters between 1991 and 2020. We observed a total of five tit species, the Great Tit (Parus major), Eurasian Blue Tit (Cyanistes caeruleus), Coal Tit (Periparus ater), Willow Tit (Poecile montanus), and Crested Tit (Lophophanes cristatus) during the surveys. The most common and abundant species were the deciduous forest preferring Great Tit and Eurasian Blue Tit, whereas the coniferous forest preferring species exhibiting a hoarding behavior, the Coal Tit, Willow Tit, and the Crested Tit, were seldom observed, and no Siberian Tits were detected. These results indicated that food-hording coniferous preferring tit species avoided urban areas. The numbers of Great Tit and Eurasian Blue Tit were greater at the end of the study period than in the first two winters studied. The average growth rate (λ) of the Great Tit and Eurasian Blue Tit increased during the winters studied. Our data indicated a greater increase rate of the Great Tit and Eurasian Blue Tit than the Finnish winter bird monitoring work, probably because we only surveyed tits within human settlements. There was a positive correlation between the average growth rate of the Great Tit and the latitude. There was a negative correlation between the changes in average growth rate (λ) of the Eurasian Blue Tit and the changes in built-up area cover within the study areas between winters 1991/1992 and 2019/2020, and vice versa, indicating that the Eurasian Blue Tit population suffered from the increase in built-up area cover. Despite the fact that the total number of winter-feeding sites decreased during the study period, changes in their numbers were not associated with the growth rates of any tit species. The abundance of the Great Tit was negatively associated with building cover and positively associated with winter temperature. The abundance of the Eurasian Blue Tit was negatively associated with building cover and negatively associated with latitude. When controlling for the latitude, the growth rate of the Great Tit increased with the temperature in winter months, indicating that the Great Tit populations have increased in colder study sites. Our results indicated that population trends of tit species may differ regionally, and that changes in urban settlements may modify the abundance of tit species during winter. We did not detect any correlation in population growth rates between species. We recommend conducting more long-term tit research both during the winter and breeding seasons to understand the population dynamics and population trends of tit species across diverse types of habitats in more detail. Full article

Petronia petronia is a highly adaptable passerine bird in the western Palearctic region. Its mitochondrial genome characteristics and intraspecific genetic variation have been poorly studied. This study sequenced and annotated the complete mitochondrial genome of P. petronia. The newly obtained mitochondrial genome was 16,895 bp in length, with an A + T content of 54.50%. By comparing this sequence with another published mitochondrial genome from a different individual of the same species, which differed in elevation by approximately 210 m. The results identified 30 nucleotide variation sites across the 13 protein-coding genes. Among these, ND5 showed the highest number of variations, while COXII and ND6 contained non-synonymous mutations. The similarity between the two control regions was only 70.60%, indicating intraspecific sequence divergence. Divergence time analysis revealed that the genus Petronia diverged from other passerine lineages around 16.5 million years ago, whereas the two haplotypes of P. petronia diverged approximately 0.26 million years ago. This study reports the complete mitochondrial genome of P. petronia and provides a preliminary description of the differences among individuals in mitochondrial sequences and structure, laying a foundation for future population genetics and comparative genomics research on this species. Full article