Great cormorants and grey herons depredating at finfish aquaculture: Factors affecting the human-wildlife conflict.

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.

Winter survival of a small predator is determined by the amount of food in hoards.

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.

The habitat preferences of invasive raccoon dog imply elevated risks for wetland-associated prey 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).

Winter-ground microhabitat use by differently coloured phenotypes affects return rate in a long-distance migratory bird.

Migratory bird populations are declining globally at alarming rates. Non-breeding site conditions affect breeding populations, but generalising non-breeding habitat conditions over large spatial regions cannot address potential fine-scale differences across landscapes or local populations. Plumage characteristics can mediate the effects of environmental conditions on individual fitness.

Optimised PCR assays for detecting elusive waterfowl from environmental DNA.

For 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 () as our focal (sub)species and sampled water from lakes, from which the presence of taiga bean goose was visually confirmed.

Anthropogenic bottom-up and top-down impacts on boreal breeding waterbirds.

Wetland habitats are changing under multiple anthropogenic pressures. Nutrient leakage and pollution modify physico-chemical state of wetlands and affect the ecosystem through bottom-up processes, while alien predators affect the ecosystems in a top-down manner. Boreal wetlands are important breeding areas for several waterbird species, the abundances of which potentially reflect both bottom-up and top-down ecosystem processes.

Large-scale genotypic identification reveals density-dependent natal dispersal patterns in an elusive bird of prey.

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.

A gradual migratory divide determines not only the direction of migration but also migration strategy of a social migrant bird.

Migratory divides separate populations of migratory animals, facilitating the evolution of intraspecific differences in migration strategies. Migration strategies are expected to be different for birds using different flyways and environments, but the knowledge regarding the impact of the flyway on individual migration strategies is scarce. By using satellite tracking and neckband resightings, we reveal the existence and structure of a gradual migratory divide between two European flyway populations of greylag geese .

Early-life diet specificity is associated with long-lasting differences in apparent survival in a generalist predator.

Early-life conditions can have long-term fitness consequences. However, it is still unclear what optimal rearing conditions are, especially for long-lived carnivores. A more diverse diet ('balanced diet') might optimize nutrient availability and allow young to make experiences with a larger diversity of prey, whereas a narrow diet breadth ('specialized diet') might result in overall higher energy net gain.

Species-specific song responses emerge as a by-product of tuning to the local dialect.

Oscine birds preferentially respond to certain sounds over others from an early age, which focuses subsequent learning onto sexually relevant songs. Songs vary both across species and, due to cultural evolution, among populations of the same species. As a result, early song responses are expected to be shaped by selection both to avoid the fitness costs of cross-species learning and to promote learning of population-typical songs.

Trophic Dynamics of Mercury in the Baltic Archipelago Sea Food Web: The Impact of Ecological and Ecophysiological Traits.

We investigated trophic dynamics of Hg in the polluted Baltic Archipelago Sea using established trophic magnification (TMFs) and biomagnification factors (BMFs) on a comprehensive set of bird, fish, and invertebrate species. As different ecological and ecophysiological species traits may affect trophic dynamics, we explored the effect of food chain (benthic, pelagic, benthopelagic) and thermoregulatory strategy on trophic total Hg (THg) dynamics, using different approaches to accommodate benthopelagic species and normalize for trophic position (TP). We observed TMFs and most BMFs greater than 1, indicating overall THg biomagnification.

Maternally transferred thyroid hormones and life-history variation in birds.

In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype.

Population differences in the length and early-life dynamics of telomeres among European pied flycatchers.

Telomere length and shortening rate are increasingly being used as biomarkers for long-term costs in ecological and evolutionary studies because of their relationships with survival and fitness. Both early-life conditions and growth, and later-life stressors can create variation in telomere shortening rate. Studies on between-population telomere length and dynamics are scarce, despite the expectation that populations exposed to varying environmental constraints would present divergent telomere length patterns.

Major population splits coincide with episodes of rapid climate change in a forest-dependent bird.

Climate change influences population demography by altering patterns of gene flow and reproductive isolation. Direct mutation rates offer the possibility for accurate dating on the within-species level but are currently only available for a handful of vertebrate species. Here, we use the first directly estimated mutation rate in birds to study the evolutionary history of pied flycatchers ().

Birds of three worlds: moult migration to high Arctic expands a boreal-temperate flyway to a third biome.

Background: Knowledge on migration patterns and flyways is a key for understanding the dynamics of migratory populations and evolution of migratory behaviour. Bird migration is usually considered to be movements between breeding and wintering areas, while less attention has been paid to other long-distance movements such as moult migration.

Methods: We use high-resolution satellite-tracking data from 58 taiga bean geese Anser fabalis fabalis from the years 2019-2020, to study their moult migration during breeding season.

Within-individual repeatability in telomere length: A meta-analysis in nonmammalian vertebrates.

Telomere length is increasingly used as a biomarker of long-term somatic state and future survival prospects. While most studies have overlooked this aspect, biological interpretations based on a given telomere length will benefit from considering the level of within-individual repeatability of telomere length through time. Therefore, we conducted a meta-analysis on 74 longitudinal studies in nonmammalian vertebrates, with the aim to establish the current pattern of within-individual repeatability in telomere length and to identify the methodological (e.

Spatial and dietary sources of elevated mercury exposure in white-tailed eagle nestlings in an Arctic freshwater environment.

Human-induced mercury (Hg) contamination is of global concern and its effects on wildlife remain of high concern, especially in environmental hotspots such as inland aquatic ecosystems. Mercury biomagnifies through the food web resulting in high exposure in apex predators, such as the white-tailed eagle (Haliaeetus albicilla), making them excellent sentinel species for environmental Hg contamination. An expanding population of white-tailed eagles is inhabiting a sparsely populated inland area in Lapland, northern Finland, mainly around two large reservoirs flooded 50 years ago.

Identifying the paths of climate effects on population dynamics: dynamic and multilevel structural equation model around the annual cycle.

How environmental factors influence population dynamics in long-distance migrants is complicated by the spatiotemporal diversity of the environment the individuals experience during the annual cycle. The effects of weather on several different aspects of life history have been well studied, but a better understanding is needed on how weather affects population dynamics through the different associated traits. We utilise 77 years of data from pied flycatcher (Ficedula hypoleuca), to identify the most relevant climate signals associated with population growth rate.

Interplays between pre- and post-natal environments affect early-life mortality, body mass and telomere dynamics in the wild.

Early-life conditions are crucial determinants of phenotype and fitness. The effects of pre- and post-natal conditions on fitness prospects have been widely studied but their interactive effects have received less attention. In birds, asynchronous hatching creates challenging developmental conditions for the last-hatched chicks, but differential allocation in last-laid eggs might help to compensate this initial handicap.

Climate change and perishable food hoards of an avian predator: Is the freezer still working?

Changing climate can modify predator-prey interactions and induce declines or local extinctions of species due to reductions in food availability. Species hoarding perishable food for overwinter survival, like predators, are predicted to be particularly susceptible to increasing temperatures. We analysed the influence of autumn and winter weather, and abundance of main prey (voles), on the food-hoarding behaviour of a generalist predator, the Eurasian pygmy owl (Glaucidium passerinum), across 16 years in Finland.

Age and sex differences in numerical responses, dietary shifts, and total responses of a generalist predator to population dynamics of main prey.

Fluctuations in the abundance of main prey species might shape animal communities, by inducing numerical responses and dietary shifts in predators. Whether numerical responses and dietary shifts differ among individuals of different age and sex has so far gained little attention. These differences could affect how much predators consume main and alternative prey, thus causing variation in predation pressure on main and alternative prey species.

Impact of continuous predator threat on telomere dynamics in parent and nestling pied flycatchers.

In addition to direct mortality, predators can have indirect effects on prey populations by affecting prey behaviour or physiology. For example, predator presence can increase stress hormone levels, which can have physiological costs. Stress exposure accelerates the shortening of telomeres (i.

Interspecific transfer of parasites following a range-shift in flycatchers.

Human-induced climate change is expected to cause major biotic changes in species distributions and thereby including escalation of novel host-parasite associations. Closely related host species that come into secondary contact are especially likely to exchange parasites and pathogens. Both the Enemy Release Hypothesis (where invading hosts escape their original parasites) and the Novel Weapon Hypothesis (where invading hosts bring new parasites that have detrimental effects on native hosts) predict that the local host will be most likely to experience a disadvantage.

Effects of interspecific coexistence on laying date and clutch size in two closely related species of hole-nesting birds.

Coexistence between great tits Parus major and blue tits Cyanistes caeruleus, but also other hole-nesting taxa, constitutes a classic example of species co-occurrence resulting in potential interference and exploitation competition for food and for breeding and roosting sites. However, the spatial and temporal variations in coexistence and its consequences for competition remain poorly understood. We used an extensive database on reproduction in nest boxes by great and blue tits based on 87 study plots across Europe and Northern Africa during 1957-2012 for a total of 19,075 great tit and 16,729 blue tit clutches to assess correlative evidence for a relationship between laying date and clutch size, respectively, and density consistent with effects of intraspecific and interspecific competition.