Leszek Jerzak

This study investigates the changes in population size, distribution, and habitat preferences of the Eurasian magpie Pica pica in Zielona Góra over 23 years, emphasising the effects of urbanisation and habitat transformation. A comprehensive survey conducted in 2022 identified 953 magpie pairs, with an average density of 8.8 pairs/km² across the current administrative boundaries of Zielona Góra (without forests), and 27.7 pairs/km² in strictly urbanised zones. The highest densities were observed in the old town (36.5 pairs/km²) and residential blocks (34.5 pairs/km²), while peripheral areas, like allotment gardens and industrial zones, showed significantly lower densities. The nests were predominantly located in coniferous trees, especially spruces, marking a shift from the previously favoured poplars. The mean nest height was 11.8 m, varying by habitat type, with the highest nests found in the old town and parks. Environmental factors, such as proximity to trash bins, water sources, and tall trees, were significant predictors of nest density and placement. These findings underscore the magpie’s adaptability to urban environments, influenced by the availability of anthropogenic resources, habitat structure, and surrounding urban features.

Insects, like many organisms, face widespread human‐driven habitat transformations which are major threats to biodiversity. However, at the same time, transformed areas including cities are increasingly being colonised by wildlife, sometimes serving as important refuges for vulnerable species. Most studies on traits that enable insects to thrive in urban environments have focused on morphology, physiology, and feeding or reproductive strategies, often overlooking behavioural traits, despite evidence from vertebrates showing that tolerance towards humans is key for wildlife to successfully colonise cities. In this study, we tested the effects of urbanisation, along with a range of life‐history, environmental and contextual traits, on tolerance towards humans—measured by flight initiation distance—in 14 Odonata (dragonflies and damselflies) species in western Poland. We found that escape distances were moderately repeatable within species. Urbanisation had a generally weak effect on Odonata escape behaviour; however, odonates delayed their escape at sites with high human presence. We also found that escape distances tended to increase with the observer’ starting distance and species‐specific body size and decrease with perch height. Additionally, male odonates were more likely to escape earlier than females. These results suggest that odonates can sense levels of anthropogenic disturbance and adjust their escape behaviour accordingly. Furthermore, our findings indicate that some basic patterns and principles commonly reported in vertebrates, such as the ability to tolerate human presence and the effect of starting distance and body mass, may also apply to invertebrates. This may have important implications for understanding the ecology and evolution of antipredator strategies in insects and their conservation.

Due to the extensive use of green urban areas as recreation places, city residents are exposed to tick-borne pathogens. The objectives of our study were (i) to determine the occurrence of ticks in urban green areas, focussing on areas used by humans such as parks, schools and kindergartens, and urban forests, and (ii) to assess the prevalence of Borrelia infections in ticks in Zielona Góra, a medium-sized city in western Poland. A total of 161 ticks representing the two species Ixodes ricinus (34 males, 51 females, 30 nymphs) and Dermacentor reticulatus (20 males, 26 females) were collected from 29 of 72 (40.3%) study sites. In total, 26.1% of the ticks (85.7% of I. ricinus and 14.3% of D. reticulatus) yielded DNA of Borrelia. The difference in the infection rate between I. ricinus and D. reticulatus was significant. Among infected ticks, the most frequent spirochete species were B. lusitaniae (50.0%) and B. afzelii (26.2%), followed by B. spielmanii (9.5%), B. valaisiana (7.1%), B. burgdorferi sensu stricto, (4.8%) and B. miyamotoi (2.4%). No co-infections were found. We did not observe a correlation in the occurrence of Borrelia spirochetes in ticks found in individual study sites that differed in terms of habitat type and height of vegetation. Our findings demonstrate that the Borrelia transmission cycles are active within urban habitats, pointing the need for monitoring of tick-borne pathogens in public green areas. They could serve as guidelines for authorities for the proper management of urban green spaces in a way that may limit tick populations and the potential health risks posed by tick-borne pathogens.

The white stork, Ciconia ciconia, is both a species familiar and charismatic to the public and a subject of extensive scientific research. Poland harbours a substantial breeding population of this species, characterized by behaviours typical of long-distance migrants. To chart a future course for research on Poland's white stork population, to deepen our understanding of its biology as well as advance conservation efforts, consultations were held with 41 Polish researchers engaged with this species. Collectively, these experts proposed 208 research queries, which were subsequently refined and condensed to 60, and each was categorized into one of 12 thematic groups identified throughout the process. An examination of the barriers to realizing these research topics (n = 60) was also undertaken. Identified impediments encompass e.g. financial limitations (12%), labour intensity (13%), and the lack of clarity in methodological directives (20%). Notably, a significant portion of these issues (42%) were deemed less appealing for scientific exploration, particularly when the anticipated impact of publication—gauged by the prestige of the scientific journal—does not align proportionately with the required time and financial investment. Nonetheless, we anticipate shifts in the priorities and practicability of these research topics, owing to substantial technological advancements in both field data acquisition and subsequent analysis. Consequently, we advocate for a continuous review process, such as a re-evaluation every 5 to 10 years, to reassess the relevancy of these topics, incorporating new ideas or potentially discarding some. Additionally, AI Chat GPT 4.0 was employed to perform similar analyses as those conducted by the authorial team. These data, which are challenging to interpret unambiguously, may also be utilized in the future for comparisons between the usefulness of topics proposed by experts and the language model.

Summary: The natural reservoirs of the nosocomial pathogen Acinetobacter baumannii are not well defined. We previously identified white storks as a model system to study the ecology of A. baumannii . Having screened more than 1,300 white stork nestlings over a period of six years across different regions of Poland and Germany (overall isolation rate of ∼29.5%), including food chain analyses and environmental samplings, we come up with a detailed picture of the dynamics and diversity of A. baumannii in their natural habitats. Adult storks, rather than being stably colonized with strains of A. baumannii which are successively transferred to their offspring, instead initially encounter these bacteria while foraging. Among their common food sources, consisting of earthworms, small mammals, and insects, we identified earthworms as a potential source of A. baumannii , but more so the associated soil as well as plant roots. Through this, hotspot soil and compost habitats were identified which enable population dynamics to be studied over the course of the year. We demonstrate that sterilized plant material is rapidly colonized by airborne A. baumannii suggesting they patrol to search for novel habitats, being opportunist by nature. The prevalence of A. baumannii exhibited a strong seasonality and peaked during summer. The strains we collected in Poland and Germany represent more than 50% of the worldwide known diversity in terms of the intrinsic OXA-51-like β-lactamase. A set of ∼400 genomes was determined and compared to a diverse set of publicly available genomes. Our pan-genome estimate of the species (∼51,000 unique genes) more than doubles the amount proposed by previous studies. Core-genome based phylogenetic analyses illustrated numerous links between wildlife isolates and hospital strains, including ancient as well as recent intercontinental transfer. Our data further suggest massive radiation within the species early after its emergence, matching with human activity during the Neolithic. Deforestation in particular seemed to set the stage for this bloom as we found that forests do not provide conducive conditions for the proliferation of A. baumannii . In contrast, wet and nutrient-rich soil alongside rivers sampled during the summer can yield an isolation rate of ∼30%. Linking published work on the interaction between A. baumannii and fungi and on aspergillosis as a major cause of mortality in white stork nestlings to our findings, we hypothesized that fungi and A. baumannii share a long history of coevolution. Interaction studies revealed the capability of A. baumannii to adhere to fungal spores and to suppress spore germination. Taken together, the intrinsic resistance endowment and potential to acquire antibiotic resistance can be explained by coevolution with antibiotic-producing fungi and other microorganisms within soil, and resistance to desiccation stress and radiation can be interpreted in the light of intercontinental hitchhiking through fungal spores. Originality - Significance: The ecology of the nosocomial pathogen Acinetobacter baumannii remains poorly understood outside the hospital. Here, we present the most comprehensive study on its environmental biology to date, after having collected more than 1,450 independent isolates of which around 400 were whole genome-sequenced. This study more than doubles the size of the pan-genome of the species, illustrating both the diversity of our collection and the bias of previous work, but also the bottleneck for the establishment of lineages within the hospital environment. We reached isolation rates of about 30% both in white stork ( Ciconia ciconia ) nestlings and in soil samples when considering for sampling all preferences of A. baumannii we uncovered. Thus, it is now possible to study the ecology and evolution of A. baumannii in nature at an unprecedented temporal and spatial resolution. We describe the worldwide spread of A. baumannii lineages in nature as an ancient phenomenon that even surpasses that of human-associated bacteria in magnitude. This is likely due to airborne spread, putatively facilitated by association with fungal spores. We propose that A. baumannii is an opportunist by nature, using airborne patrolling to rapidly enter new suitable habitats consisting of organic matter in early stages of decomposition. Our collective data suggest that A. baumannii , early after its speciation, went through massive radiation during the Neolithic, likely due to deforestation, settlement and farming producing numerous favorable habitats. Their natural lifestyle, which requires rapid adaptability to various habitats as well as tolerance to desiccation, radiation and antibiotic stress, perfectly predispose these opportunistic pathogens to establish within the hospital setting. Comparison of genomes from environmental and clinical isolates will now enable studies of the adaptive evolution of environmental bacteria towards multidrug-resistant opportunistic pathogens.

Pollution by anthropogenic litter is a major threat to global ecosystems. Seabirds are frequently used as environmental monitors of litter ingestion, but similar research is rare for terrestrial birds. Here, we focused on pellet analysis from 117 nests of an iconic bird of the Western Palearctic, the white stork (Ciconia ciconia), breeding in southern and southwestern Poland in a farmland landscape, far away from large dumps and landfills. We found that most prey items in the diet of white storks were invertebrates (particularly from orders Coleoptera, Orthoptera, and Hymenoptera) but vertebrate prey comprised most of the biomass. Further analysis revealed that anthropogenic litter was found in 22.7% of pellets (34.2% of breeding pairs) with plastic (8.4%) and cigarette filters (6.9%) being most prevalent. This study represents the first assessment through pellet analysis of the ingestion of anthropogenic litter by live wild storks in Poland and also by a migratory population of white storks. Our study indicates a potentially significant transfer of plastic and other anthropogenic material through terrestrial food webs.

Understanding habitat and spatial overlap in sympatric species of urban areas would aid in predicting species and community modifications in response to global change. Habitat overlap has been widely investigated for specialist species but neglected for generalists living in urban settings. Many corvid species are generalists and are adapted to urban areas. This work aimed to determine the urban habitat requirements and spatial overlap of five corvid species in sixteen European cities during the breeding season. All five studied corvid species had high overlap in their habitat selection while still having particular tendencies. We found three species, the Carrion/Hooded Crow, Rook, and Eurasian Magpie, selected open habitats. The Western Jackdaw avoided areas with bare soil cover, and the Eurasian Jay chose more forested areas. The species with similar habitat selection also had congruent spatial distributions. Our results indicate that although the corvids had some tendencies regarding habitat selection, as generalists, they still tolerated a wide range of urban habitats, which resulted in high overlap in their habitat niches and spatial distributions.

Incubation behaviour is essential for understanding the reproductive success in birds. For example, the orientation of the bird is important for reducing incubation costs associated with wind or sun, but on the other hand can be modified by the perceived risk of predation. We studied the body position of incubating White Stork Ciconia ciconia in eastern Poland using a small unmanned aerial vehicle (drone). The head and body orientation of the incubating storks was non-random and modified by natural factors, mainly wind direction and speed, but also by the presence of an apex predator, the White-tailed Eagle Haliaeetus albicilla. However, head orientation during incubation in nests located on electricity poles was also modified by the presence of the power lines, probably due to disturbance in the magnetic field detected by birds. Surprisingly, although the positioning of incubating birds (mainly females) is very important for the detection of predators and for reducing energy costs, these have not previously been studied. New technologies, such as drones, make it possible to collect new, extensive information on the incubation behaviour of birds.

The Magpie Pica pica occurs all over open agricultural areas in Poland, especially near human settlements (particularly in western Poland). The aim of this study was to estimate the size of the local Magpie population and characterize, in detail, nest site selection in a medium size city Górzów Wlkp. in the XXI century. For this study, the whole city was divided into a total of 114 squares of 1 × 1 km. Data were collected in spring 2014. A total of 474 Magpie pairs were recorded. The average density was 5.5 pairs/km² (min = 0, max = 22 nests/square), in the non-urbanized habitat type—3.7 p/km², and in the urbanized habitat type—13.5 p/km². Magpie nests were found most often on Spruces Picea sp. and Poplars Populus sp. The mean height of the nest site was 11.5 m, while the mean height of trees used for nesting was 13.4 m. The type of tree arrangement most frequently used for nesting was tree rows (26.3%), followed by single trees (24.6%) and clusters of 4–10 trees (20.1%). The results for the Magpie’s environmental preferences do not differ from the general patterns described earlier. The study shows that magpies can adapt to changing urbanization factors, and changes in the choice of conifers help the species to adapt to highly anthropogenic habitats.

Access to food is crucial in the life of birds and affects reproduction, survival and, consequently, population size. In the case of bird species inhabiting villages, poorer food conditions now exist, mainly because of changes in the lifestyle of rural residents and a reduction in the number of farm animals traditionally housed in backyards. Recent changes have also affected dog populations in villages, and the majority of them are no longer kept outside as guard dogs, but rather inside houses as pets. We investigated how traditional care of dogs impacted rural birds and other animal populations. The study was carried out at the end of winter and early spring in 29 farmsteads in western Poland. Using camera traps, it was found that the food fed to dogs was also taken by seven species of birds and at least three species of mammals. The most numerous species taking dog food was the house sparrow, Passer domesticus, which is declining in Europe. In the case of this species, females were more likely than males to use food given to dogs, with a clear preference for food prepared in the human kitchen. We conclude that the food provided to domestic pets can be an important component of the diet of wild birds and mammals living close to humans.