Intensive forestry management, particularly clearcutting, threatens boreal biodiversity by reducing critical habitat for specialist species such as resident forest birds. Research on clearcutting often emphasizes the breeding season, primarily reflecting migratory birds, while year-round resident birds-more exposed to local disturbances-remain understudied. Moreover, cross-sectional studies dominate, limiting our ability to detect the clearcutting's true impact. Using a Before-After Control-Impact (BACI) design coupled with Passive Acoustic Monitoring (PAM), we investigated how clearcutting affects 12 resident forest birds in Southwest Finland. Acoustic data were collected before (2020) and after (2024) clearcutting across 60 sites: 30 control (uncut) and 30 impact (clearcut) sites. Impact sites were further categorized into low-impact (6.45-<33.87%) and high-impact (>33.87-100%) areas based on the proportion of forest removed within a 100-meter radius. Total vocal activity declined significantly at high-impact sites, whereas species richness showed no clear response. Species-specific analyses revealed negative responses for Crested Tit, Eurasian Treecreeper, and Goldcrest, with Eurasian Treecreeper particularly sensitive, declining at even low-impact sites. In contrast, the Black Woodpecker vocal activity increased at high-impact sites. Our results demonstrate that observed changes stemmed from clearcutting rather than natural variation. Our findings highlight that intensive clearcutting substantially reduces resident bird activity in boreal forests, emphasizing the need for sustainable forest management practices, including tree retention strategies, selective harvesting, and species-specific conservation measures. The present study represents one of the first applications of BACI design with PAM for assessing the clearcutting impacts on resident forest birds, providing valuable insights for evidence-based forest management and biodiversity conservation.

Successful conservation and management actions to safeguard migratory huntable waterbirds require knowledge of their spatio-temporal distributions and migration patterns throughout the annual cycle. Such actions are challenging, because migration patterns within a population can vary, for example, due to migratory barriers and sex-specific factors. We studied individual migratory patterns of East Atlantic flyway Eurasian wigeon (Mareca penelope), using GPS-tracking data from birds caught during spring in central and northern Europe. We found complex migratory patterns and differences in the spring migration of wigeon captured in central and northern Europe. These wigeon migrated south and north of the Baltic Sea, respectively, despite the Baltic Sea presenting no barrier to the population. Wigeon captured in central Europe moved northeast towards northern Russia, differing from movements of the birds captured in northern Europe, which were more varied and tended to migrate toward the northeast and northwest. Autumn migration orientation of birds from both capture areas was towards the southwest, resulting in Scandinavian breeding birds undertaking loop migration. Moult migrating males moved further during the summer than females, reducing migratory connectivity among males and reflecting sex-specific differences in the migratory behaviour of Eurasian wigeon. Our results confirm that individual migratory patterns of Eurasian wigeon show more diversity than expected from ring recovery data, suggesting that successful management at flyway-population level needs more detailed information to support management planning.

Over the past few decades, Europe has made significant efforts to restore and construct wetlands to halt the ongoing habitat and biodiversity losses. These endeavours require considerable time, investment, and effort, making it crucial to ensure that they are highly effective in achieving their objectives, one of which is biodiversity conservation, including waterbirds. We monitored waterfowl communities at 146 constructed wetlands in unprotected landscapes across Finland. We studied the effects of habitat and landscape (at two spatial scales) variables on four breeding waterfowl metrics - species richness, pair abundance, brood abundance, and mean brood size. We also investigated how these metrics vary as wetlands age over time, and depending on gull populations. We found that wetlands with larger perimeters, more islands, and greater gull abundance supported higher species richness and more breeding pairs and broods. However, mean brood size was unexpectedly lower at wetlands with more islands. Pair and brood abundance peaked seven and four years after establishment, respectively, while species richness declined linearly with age. At the local scale (200 m), wetlands surrounded by more peat-associated elements and built-up cover had lower species richness and mean brood size, respectively. Brood abundance was higher in wetlands surrounded by broad-leaved forest at both the local and regional (2 km) scale, while regional marsh cover positively influenced species richness and pair abundance. Such findings provide valuable feedback on wetland construction and restoration projects, helping to ensure that future initiatives can improve their biodiversity conservation outcomes.

Widespread forestry operations have simplified and fragmented boreal forest structure across Europe, reducing key features such as deadwood and peatlands that support forest specialist species. The Willow Tit (Poecile montanus), a declining boreal passerine, is highly sensitive to such changes. While its breeding-season habitat associations are relatively well studied, much less is known about its habitat use during the pre-breeding period, a critical phase of territory establishment that may influence reproductive success. We used passive acoustic monitoring (PAM) at 285 forest sites across a managed boreal landscape in southern Finland to investigate earlyseason Willow Tit occurrence in relation to forest structure. Species presence was modeled as a function of habitat structure (e.g., modeled deadwood potential, peatland type, foliage biomass, forest age), biotic interactions (presence of Pygmy Owl (Glaucidium passerinum) and Crested Tit (Lophophanes cristatus)), and proximity to human settlements, at two spatial scales (100 m and 400 m buffers). Willow Tit presence was consistently and positively associated with the area of pine mires, highlighting the ecological value of these pinedominated peatlands during territory settlement. In contrast, mature forest area and modeled deadwood potential showed no positive effects; the latter exhibited a weak negative association at the landscape scale. This pattern may indicate that modeled deadwood estimates do not fully capture the fine-scale characteristics relevant for Willow Tits during the pre-breeding period, or that decaying wood plays a more limited role in habitat selection at this stage than at later stages of breeding. Detection probability declined with Julian date, likely reflecting seasonal changes in vocal activity. These findings emphasize the ecological and management importance of preserving pine mires and suggest that widely used forest inventory models may overlook key habitat features essential for declining species. We recommend integrating peatland preservation into forestry planning to enhance habitat suitability and resilience under intensive forest management and climate change.

Understanding the demographic mechanisms underlying population decline or recovery is critical for conservation and management, yet similar population trends may arise from very different underlying processes. Comparing populations of vulnerable species groups like long-lived raptors in different environments can reveal how species respond to change. Here, we explore the demographic drivers of population recovery in two white-tailed eagle Haliaeetus albicilla populations, for which we have comprehensive data available: a mainly coastal population in the Baltic Sea region and an Arctic inland freshwater population primarily in Lapland. We analysed over 50 years of data, including breeding pair counts, productivity, ringing records, visual resightings, and genetic identification of individuals at natal nests and breeding sites. These data were combined in a Bayesian age-structured integrated population model to estimate key demographic parameters, population trends, and conduct prospective and retrospective analyses. Both populations experienced similar growth rates (Baltic Sea: 8.7% (CRI = -1.1%-16.8%), Lapland: 8.8% (CRI = -7.0-28.0%)) primarily supported by high adult survival typical for long-lived species. Despite these similar growth rates, demographic pathways differed markedly between populations: subadult survival being higher in the Baltic Sea, whereas adult survival was higher in Lapland. Both populations showed evidence of negative density dependence, and in the Baltic Sea population this appeared to operate primarily through delayed recruitment. This was associated with an increase in the non-breeding floater cohorts, suggesting increasing constraints on recruitment into the breeding population. Our results demonstrate that comparable population growth can be sustained by contrasting demographic structures, implying that monitoring and management strategies should account for population-specific processes rather than relying on trends alone. More broadly, this study highlights the value of long-term, multi-source data and integrated demographic modelling for identifying density-dependent mechanisms and understanding recovery dynamics in long-lived species.

Animal movements contribute to the spread of infectious diseases and are driven in part by environmental conditions. We investigated the links among the environment, animal movement, and infectious disease dynamics in waterfowl, which are among the primary wildlife hosts of avian influenza viruses. By combining telemetry data on 4606 individuals from 26 waterfowl species with data on land cover, weather, and vegetation, we found that waterfowl moved less in areas of higher land cover heterogeneity and higher human population density. Moreover, predicted waterfowl movement distances were weakly but positively correlated with distances between detections of H5N1 highly pathogenic avian influenza in wild waterfowl, suggesting that environmental conditions might contribute to the spread of this disease via their effects on bird movements. By considering wildlife movements alongside other drivers of infectious disease dynamics, such as livestock production and human mobility, we move closer to predicting outbreaks and informing interventions.

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.

The use of predator control as a conservation tool, for example to protect ground-nesting bird populations, remains a subject of ongoing debate. To justify the control or eradication of a predator, managers need to provide evidence on the success of the program. We evaluated the effectiveness of a raccoon dog control program (2021–2024) organized by governmental bodies around wetlands important for waterfowl conservation in Finland. The raccoon dog is an invasive species and a nest predator of waterfowl. We assessed control effectiveness by analysing how hunting methods and effort influenced catch and how varying hunting intensity across wetlands affected raccoon dog abundance measured with camera-traps. There was a moderate negative relationship between previous hunting efforts and monthly catch, indicating diminishing returns, but full eradication was not achieved. Among the four used hunting methods, hunting from dens proved the most efficient hunting method in relation to time used. The impact of catch on the subsequent number of camera-trap observations varied. Winter camera-trap data from feeding sites showed no decline in raccoon dog presence, potentially due to autumn immigration. However, hunting success showed a negative effect on raccoon dog camera-trap observations in spring (waterfowl breeding season), suggesting a substantial, but incomplete, raccoon dog population reduction. Consistent with this, raccoon dog predation of artificial nests decreased, without compensatory increases by other predator species, resulting overall in reduced nest predation. We conclude that control efforts reduce raccoon dog numbers and potentially benefit wetland bird species, but long-term success requires substantial and sustained effort.

The hoarding behaviour of animals has evolved to reduce starvation risk when food resources are scarce, but effects of food limitation on survival of hoarding animals is poorly understood. Eurasian pygmy owls (Glaucidium passerinum) hoard small mammals and birds in natural cavities and nest boxes in late autumn for later use in the following winter. We studied the relative influence of the food biomass in hoards of pygmy owls on their over-winter and over-summer apparent survival. We also tested whether this influence is modulated by intrinsic (age, sex) traits or extrinsic factors (winter temperature, snow depth). We measured biomass of prey items in pygmy owl food-hoards during autumns 2003-2023 in west-central Finland. We individually marked and recaptured pygmy owls both at nests in the breeding season and at food-hoards. Our dataset included a total of 407 pygmy owls, which were all captured from a food-hoard at least once during their capture history. The mean biomass of the annual food-hoards associated with one individual was 443 g (SD = 523 g, range from 3.5 to 4505 g) and was markedly higher in autumns of vole abundance than in those of vole scarcity. Hoard size had a positive effect on apparent survival of owls over consecutive winter, whereas it did not affect apparent survival over next summer. Hoard size was a better predictor of apparent survival than vole abundance (main food of pygmy owls) in the field. Male owls had higher overall apparent survival rates than female owls, particularly when food-hoards were small. That hoard size was a better predictor of apparent survival than vole abundance indicates that the hoards are critical for pygmy owls during winter, likely because they are unable to hunt voles below deep snow cover. The positive relationship between apparent survival of owl individuals and their hoard size during winter (when the hoard is being consumed), but not summer, indicates that the hoard size has a true positive effect on survival, and does not only reflect latent inter-individual differences and/or dissimilarities in their environments. We conclude that food limitation during hoarding essentially regulates apparent over-winter survival of pygmy owl individuals.

Sustainable aquaculture requires consideration of its interactions with wildlife. Human–wildlife conflicts arise when piscivorous birds, such as cormorants and herons, depredate in fish farms. By surveillance cameras, we quantified the depredation pressure of birds at fish farms along the Finnish coast. The pressure varied considerably between farms, from no bird visits to daily losses of hundreds of fish. Grey herons were most numerous and depredated 2–5 times more fish than cormorants, which are commonly regarded bigger threats. Depredation rates decreased with the increasing fish size even though cormorants also took large fish. Piscivorous raptors seldom foraged in farms but were interested in larger fish. Proximity to bird breeding colonies did not affect the predation pressure. Protective nets were effective against raptors and cormorants, but grey herons used them as depredation platforms. Knowledge on factors explaining depredation rates is valuable for science-based planning of measures to mitigate the human–wildlife conflict.

The population size of great cormorants, Phalacrocorax carbo sinensis, has risen steeply in the Baltic Sea over the past 40 years. The growing population has resulted in polarized conflicts between conservation and coastal fisheries due to the losses cormorants may inflict on fisheries. Mitigation of the conflicts requires objective estimates of true losses to fisheries, but quantitative research on losses has been scarce. We used continuous videorecordings to systematically quantify cormorant visits and their activity at 15 fyke nets during the 2022-2023 breeding and post breeding seasons. More than 2400 h of video footage were recorded, in which cormorants were found for 664 h. We also quantified the frequency of fish injured by birds in coastal fishing catches using data from the EU Fisheries Data Collection Program including data from fyke nets and gill nets. Our results show that cormorants frequently foraged in open, floating fyke nets but relatively rarely in submerged nets, leading to significantly higher losses in the former. Monitoring data from fyke and gill net catches covering the entire Finnish coast revealed that the proportion of bird-injured fish in catches is very modest (0.5 %) but can be considerable in individual catches. Finally, results indicate that cormorant visits and the proportion of injured fish in the catch tend to increase when distance to the nearest cormorant colony decreases. We conclude that the losses caused by birds are generally modest, except in open fyke nets where cormorants may conduct hundreds of dives and catch dozens of fish a day. Our study shows that cormorant depredation is highly variable in time and space, but also partly manageable by selecting gear that conforms to local cormorant pressures. We underline the importance of systematic scientific research when measuring damage caused by cormorants and ask for evidencebased political strategies to mitigate perceived cormorant problems.

The recovery of some apex predators has led to concerns for endangered prey that may have developed risky habitat selection tactics during predator-free eras. Environmental heterogeneity affects predator–prey coexistence, but spatial redistribution of prey has rarely been studied. A predator–prey system with white-tailed eagles and common eiders provides a unique opportunity to study the effect of returning predators on an abundant but declining prey population. Our objective was to investigate how the physical environment affects predator–prey relationships and subsequently the spatial redistribution of the prey population over time, and to perform a large-scale assessment of the population status and distribution of eiders in the North-Eastern Baltic Sea. Using extensive survey data from the Finnish coast from 1997 to 2020 on predator and prey breeding numbers, we constructed a spatiotemporal model explaining the distribution of eiders on > 3600 islands across highly variable coastal regions. We assessed how the proximity of nesting eagles affected eider abundance, mediated by properties related to physical nest shelter (archipelago type and island forest cover). Breeding eider numbers decreased on exposed islands particularly near eagle nests, while they increased near eagle nests in the sheltered archipelago. We observed population-scale predator-induced shifts in the breeding distribution, likely reflecting both excess mortality on exposed islands and a shift of the population core to low-risk habitats. We show that a returning predator can affect the distribution and density of its prey in a habitat-specific manner, which is important to consider in parallel with effects of human-induced ecosystem changes during conservation planning.

The recovery of threatened species after conservation measures can lead to human-wildlife conflicts. One example of such is the recent population growth of the Barnacle Goose Branta leucopsis, a large herbivorous bird. During migration, geese stage in large numbers on agricultural fields in range countries and cause substantial damage to farms. A combination of repelling fields, where geese were chased off by humans, and accommodation fields, which provide refuge sites for foraging geese, has been suggested as an effective management tool to mitigate conflicts. Using high-resolution satellite tracking data, we investigated habitat selection of 41 barnacle geese staging in Northern Karelia, Finland, during spring 2021. We estimated relative habitat use by these geese and conducted a fine-scale analysis of their use of different fields by employing Hidden Markov Models and integrated step-selection analysis. Fields included normal crop (no goose management), project and other (private and Nature 2000 area) accommodation fields and repelling fields. Project accommodation and repelling fields were established on areas known to have a long history of high grazing pressure by barnacle geese. We found that behavioural data of geese can be categorized into three different states (static, slow and fast movement). Static and slow states were used for local field selection, fast state for field selection in the regional area, and all states for field selection after leaving a repelling field. Overall, relative habitat use indicated that geese utilize accommodation fields more than expected by their availability. Integrated step-selection analyses revealed that geese avoided normal and repelling versus project accommodation fields at the regional scale. At the local scale, they preferred project accommodation fields over all other fields. After leaving a repelling field, geese did not show preference for any accommodation over repelling fields. Synthesis and application. Geese show individual selection for accommodation fields compared to normal or repelling fields across several scales. Our results suggest that the accommodation field concept-consisting of refuge areas and no-go areas where geese are repelled from-can help to mitigate the human-wildlife conflict using local stakeholders' knowledge. Uhanalaisten lajien suojelutoimien onnistuminen voi johtaa ihmisen ja villiel & auml;inten v & auml;lisiin konflikteihin. Yksi esimerkki t & auml;st & auml; on valkoposkihanhien (Branta leucopsis) populaation kasvu. Muuttoaikoina hanhet ker & auml;& auml;ntyv & auml;t suurina joukkoina viljelyspelloille ja voivat aiheuttaa merkitt & auml;v & auml;& auml; vahinkoa viljelykasveille ja taloudellisia menetyksi & auml; maanviljelij & ouml;ille. Hanhipeltokonseptia, joka koostuu hanhipelloista-joissa hanhet saavat ruokailla ja lev & auml;t & auml; rauhassa-ja karkotuspelloista-joista hanhet karkotetaan-on ehdotettu tehokkaaksi hallintakeinoksi konfliktien lievent & auml;miseksi. Tutkimme hanhipeltokonseptin toimivuutta Pohjois-Karjalassa kev & auml;& auml;ll & auml; 2021 tutkimalla 41 satelliittiseurannassa olleen valkoposkihanhen elinymp & auml;rist & ouml;valintaa. Arvioimme n & auml;iden hanhien suhteellista peltojen ja elinymp & auml;rist & ouml;n k & auml;ytt & ouml;& auml; k & auml;ytt & auml;m & auml;ll & auml; integroitua askelvalinta-analyysi & auml;. Pellot sis & auml;lsiv & auml;t normaalia viljelyaluetta (ei aktiivista hanhien hallintaa), hankkeen ja muiden (yksityisten ja Natura 2000 -alueiden) hanhipeltoja sek & auml; karkotuspeltoja. Hanhi- ja karkotuspellot perustettiin alueille, joita hanhien tiedettiin suosivan ruokailualueina. Hanhien k & auml;ytt & auml;ytyminen voitiin luokitella kolmeen eri tilaan (staattinen, hidas ja nopea liike). Staattista ja hidasta tilaa k & auml;ytettiin paikalliseen peltovalintaan, nopeaa tilaa alueelliseen peltovalintaan, ja kaikkia tiloja k & auml;ytettiin peltovalintaan karkotuspellolta poistumisen j & auml;lkeen. Suhteellinen elinymp & auml;rist & ouml;n k & auml;ytt & ouml; osoitti, ett & auml; hanhet k & auml;yttiv & auml;t hanhipeltoja enemm & auml;n kuin niiden saatavuuden perusteella voisi odottaa. Askelvalinta-analyysit osoittivat, ett & auml; hanhet v & auml;lttiv & auml;t normaaleja ja karkotuspeltoja hankkeen perustamiin hanhipeltoihin verrattuna alueellisella tasolla. Paikallisella tasolla ne suosivat hankkeen hanhipeltoja kaikkiin muihin peltoihin verrattuna. Karkotuspellon j & auml;tt & auml;misen j & auml;lkeen hanhet eiv & auml;t tehneet eroa hanhi- ja karkotuspeltojen v & auml;lill & auml;. Synteesi ja sovellus: Hanhet suosivat paikanvalinnassaan hanhipeltoja verrattuna normaaleihin ja karkotuspeltoihin useilla tasoilla. Tuloksemme viittaavat siihen, ett & auml; hanhipeltokonsepti voi auttaa lievent & auml;m & auml;& auml;n ihmisen ja villiel & auml;inten v & auml;list & auml; konfliktia hy & ouml;dynt & auml;en paikallisten sidosryhmien tiet & auml;myst & auml;.

Habitat imprinting is the phenomenon where exposure to cues in the natal habitat increases the probability of choosing a habitat with similar cues later in life. It is considered a key behavioural mechanism that decreases the costs associated with habitat selection. The similarity of breeding to natal habitats can be especially beneficial when choosing the first breeding site and when the choice has long‐term consequences due to high site fidelity. Habitat imprinting in breeding habitat selection has rarely been documented in wild animals living in unmanipulated environments and is challenging to study in long‐lived species with delayed maturity. We used a combination of genetic and visual identification to identify 354 white‐tailed eagles Haliaeetus albicilla hatched between 1991 and 2015 that were subsequently documented breeding between 2001 and 2023 along the Baltic Sea coast or in the inland environments. We examined (a) the similarity of natal and breeding habitats and (b) the effects of natal dispersal distance on this similarity. Furthermore, (c) we were interested in breeding habitat selection and tested whether eagles showed a preference for natal‐like habitats among suitable territories that were at the time still unoccupied. We found that breeding habitats were similar to natal habitats, independent of natal dispersal distance. Eagles were also more likely to choose a natal‐like breeding site among available alternative sites. These results indicate that habitat imprinting is a possible driving mechanism in the habitat selection of long‐lived animals with delayed maturity and has important implications for conservation actions such as eagle reintroduction programmes.

Migratory waterfowl are a harvested resource shared among multiple European countries, exposing them to potential overexploitation. Management of take is challenging since the life cycle of migratory waterfowl consists of several stages distributed among several locations, with possible spatio-temporal overlap among populations with differing population trends. Successful harvest management in such situations requires knowledge about the connections between breeding and non-breeding locations, and where birds are harvested. Breeding populations of Eurasian wigeon (Mareca penelope) are declining in Finland, underlining the need for more effective harvest management. Relative proportions and temporal distribution of local breeding birds and migrants from a larger Russian breeding population within the Finnish hunting bag has been unknown to date. We studied spatio-temporal origins of Finnish harvested wigeon by measuring stable-hydrogen (δ2H) isotope values from legally harvested birds. We modelled the changes in δ2H values of the feather samples within the hunting season using Gaussian processes and found that the origin of harvested wigeon in Finland changed during the hunting season and differed by age and sex. In juveniles and adult females but not in adult males, origin of harvested birds shifted from local and possibly western Russian birds to more long-distance migratory birds during the harvest season. These patterns likely reflected sex- and age-specific differences in migratory behaviour of Eurasian wigeon in the East Atlantic flyway, which can be used to guide future management and conservation of this species through the implementation of spatio-temporal harvest regulation.

Sensitivity of bird species to environmental metal pollution varies but there is currently no general framework to predict species-specific sensitivity. Such information would be valuable from a conservation point-of-view. Calcium (Ca) has antagonistic effects on metal toxicity and studies with some common model species show that low dietary and circulating calcium (Ca) levels indicate higher sensitivity to harmful effects of toxic metals. Here we measured fecal Ca and five other macroelement (Potassium K, Magnesium Mg, Sodium Na, Phosphorus P, Sulphur S) concentrations as proxies for dietary levels in 66 bird species to better understand their interspecific variation and potential use as an indicator of metal sensitivity in a wider range of species (the main analyses include 39 species). We found marked interspecific differences in fecal Ca concentration, which correlated positively with Mg and negatively with Na, P and S levels. Lowest Ca concentrations were found in insectivorous species and especially aerial foragers, such as swifts (Apodidae) and swallows (Hirundinidae). Instead, ground foraging species like starlings (Sturnidae), sparrows (Passeridae), cranes (Gruidae) and larks (Alaudidae) showed relatively high fecal Ca levels. Independent of phylogeny, insectivorous diet and aerial foraging seem to indicate low Ca levels and potential sensitivity to toxic metals. Our results, together with information published on fecal Ca levels and toxic metal impacts, suggest that fecal Ca levels are a promising new tool to evaluate potential metal-sensitivity of birds, and we encourage gathering such information in other bird species. Information on the effects of metals on breeding parameters in a wider range of bird species would also help in ranking species by their sensitivity to metal pollution.

Wind power plays a vital role in global climate action and plans for new turbines in the Baltic Sea region are underway. However, it is crucial not to overlook the environmental impact on wildlife, which can be difficult to quantify, especially in elusive and hard-to-track species. One of these species is the white-tailed eagle, a conservation success story that faces a significant collision risk with rotor blades, particularly as turbines are being constructed in its coastal habitats. To assess the effect of wind turbines on survival of territorial adults, we genotyped DNA from adult feathers collected at nests between 2010 and 2022. By tracking individuals across years, we measured survival and breeding dispersal in relation to wind turbine presence. Turbines within a 5 km radius of nests were found to reduce annual survival rates by 7.6 %, while resighting probability and breeding dispersal probability were unaffected. The proportion of territories exposed to wind turbines is currently low (4-5 %), mainly because recent construction sites have been further inland. However, future projections suggest an increase in territory exposure, indicating potential for population-level risks. This highlights the need for substantial safety buffers around nest sites (preferably >5 km) to protect the breeding white-tailed eagle population. Currently, a comprehensive understanding of the large-scale impact on the Baltic Sea white-tailed eagle population is lacking. As wind power expands, it is necessary to consider its impact on wildlife and we recommend conducting ongoing environmental assessments to monitor and adapt conservation measures.

Background Natal dispersal, the distance between site of birth and site of first breeding, has a fundamental role in population dynamics and species’ responses to environmental changes. Population density is considered a key driver of natal dispersal. However, few studies have been able to examine densities at both the natal and the settlement site, which is critical for understanding the role of density in dispersal. Additionally, the role of density on natal dispersal remains poorly understood in long-lived and slowly reproducing species, due to their prolonged dispersal periods and often elusive nature. We studied the natal dispersal of the white-tailed eagle ( Haliaeetus albicilla ) in response to local breeder densities. We investigated the effects of the number of active territories around the natal site on (a) natal dispersal distance and (b) the difference between natal and settlement site breeder density. We were interested in whether eagles showed tendencies of conspecific attraction (positive density-dependence) or intraspecific competition (negative density-dependence) and how this related to settlement site breeder density. Methods We used a combination of long-term visual and genotypic identification to match individuals from their breeding site to their natal nest. We identified natal dispersal events for 355 individuals hatched between 1984 and 2015 in the Baltic Sea coast and Arctic areas of Finland. Of those, 251 were identified by their genotype. Results Individuals born in high-density areas dispersed shorter distances than those born in low-density areas, but settled at lower density breeding sites in comparison to their natal site. Eagles born in low natal area densities dispersed farther but settled in higher density breeding sites compared to their natal site. Conclusions We show that eagles might be attracted by conspecifics (positive density-dependence) to identify high-quality habitats or find mates, but do not settle in the most densely populated areas. This indicates that natal dispersal is affected by an interplay of conspecific attraction and intraspecific competition, which has implications for population dynamics of white-tailed eagles, but also other top predators. Furthermore, our study demonstrates the value of long-term collection of both nestling and (non-invasive) adult DNA samples, and thereafter using genotype matching to identify individuals in long-lived and elusive species.

Habitat preferences of invasive predators determine where and for which prey species they pose a threat upon. This is crucial information for the conservation of endangered prey species because invasive predators pose additional predation on top of that caused by natural predators. In large parts of Europe, the most common invasive mesopredator is the raccoon dog (Nyctereutes procyonoides). To understand the risk that the raccoon dog poses for wetland-associated species, we collected information about its habitat preferences near these habitats. We used data on 24 GPS-collared raccoon dogs from three landscape types in Finland, to study their spatial and temporal habitat preferences. We first determined their home ranges, within which we then examined habitat use and preferences. Raccoon dogs showed generalist habitat use, which was evident in their wide range of used habitats. However, in spring and summer, during the breeding seasons of waterfowl and amphibians, they preferred wetlands and peatlands. They also preferred shorelines and the edges of forests and agricultural fields. During autumn and winter, raccoon dogs did not prefer wetlands. These findings support the conclusion that the raccoon dog’s habitat preferences pose a particular threat to wetland-associated species, such as nesting waterfowl and amphibians. The species’ habitat preferences coupled with high numbers of this invasive mesopredator pose additional predation for endangered wetland-associated species on top of that of native predators.

AbstractFor many aquatic and semiaquatic mammal, amphibian and fish species, environmental DNA (eDNA) methods are employed to detect species distribution and to monitor their presence, but eDNA is much less employed for avian species. Here, we developed primers for the detection of true geese and swan species using eDNA and optimised a PCR protocol for eDNA. We selected taiga bean goose (Anser fabalis fabalis) as our focal (sub)species and sampled water from lakes, from which the presence of taiga bean goose was visually confirmed. To test, if taiga bean goose DNA could be detected among DNA of other goose species, we similarly sampled eDNA from a zoo pond housing several Anatidae species. We were able to detect taiga bean goose DNA in all but one of the tested lakes, including the zoo pond. The primers developed are not species‐specific, but rather specific to the genus Anser, due to the close relatedness of Anser species, which prevented the development of species‐specific primers and the use of, for example, quantitative PCR. We also developed eDNA primers for Branta species and Cygnus species and tested these primers using the same samples. Canada goose (B. canadensis) and barnacle goose (B. leucopsis) DNA were only detected in the zoo pond (in which they were present), as the sampled natural lakes fall outside the range of these species. We detected whooper swan (C. cygnus) DNA in three lakes and the zoo pond (in which the species was present). The eDNA method presented here provides a potential means to monitor elusive goose species and to study the co‐occurrence of large waterfowl.