Ülo Väli

Estonian University of Life Sciences | EMU · Chair of Biodiversity and Nature Tourism

The relative contributions of genetic and social factors in shaping the living world are a crucial question in ecology. The annual migration of birds to their wintering grounds and back provides significant knowledge in this field of research. Migratory movements are predominantly genetically determined in passerine birds, while in large soaring bi...

Context Biodiversity is closely related to landscape heterogeneity, but both are difficult to evaluate directly. Apex predators, such as raptors, are potential surrogate indicators of diversity, but previous studies using a correlative approach have been heavily criticised. Objectives We evaluated whether space use by a generalist avian predator, t...

Characterizing the genetic diversity and structure of populations is essential for understanding their evolutionary history and planning species conservation. The lesser spotted eagle (Clanga pomarina) is a large migratory raptor with a relatively small breeding range concentrated in Eastern Europe. We evaluated the level of genetic diversity and p...

Species coexist only when occupying different ecological niches. We evaluated habitat and trophic niches in two recently diverged hybridising avian apex predators, the declining Greater Spotted Eagle Clanga clanga (mainly found in contracting wetlands) and the more numerous Lesser Spotted Eagle Clanga pomarina (inhabiting mosaic farmlands). We trac...

Citizen science is increasingly contributing to ecology and conservation research, mostly by the extensive collection of field data. Although webcams attract numerous observers, they have been underused in this respect. We used prey delivery records deposited by citizen scientists in an internet forum linked to webcams to explore the diet compositi...

Monitoring of biodiversity in expanding urban areas is an essential part of wildlife conservation. There is evidence that raptors, such as Northern Goshawks (Accipiter gentilis), are effective bioindicator species in urban areas, however, their relationship with other bird populations is not clearly established. We asked whether activity patterns o...

The northern hawk owl is a real irruptive species that respond to irregular changes in the food supply. When prey levels are adequate, it breeds and winters within northern forests. Decreased prey availability can start winter invasions, the timing and magnitude of which are the subject of this study. Mainly the citizen data were extracted from the...

Biodiversity is often highest at ecotones. However, edge effects vary among species and the spatial extent has rarely been quantified. Rodents form an important part of the food chain and thus are keystones of the ecosystem. We measured the species richness and abundance of rodents at ecotones between forests and three types of open agricultural bi...

Our study aims to increase the understanding about the impacts of potential drivers of pollen richness by using a pollen-vegetation modelling approach. We used the Sutton-Prentice dispersal model implemented in the HUMPOL software suite to explore the effects of factors commonly associated with pollen richness: vegetation diversity (plant richness...

Understanding connectivity between migratory bird breeding and wintering grounds is essential for range-wide planning of conservation activities. We used GPS tracking to explore the migration of 28 ‘Endangered’ Greater Spotted Eagles, Clanga clanga from three remaining European breeding populations towards their wintering range, and to identify pop...

In Estonia, the black stork (Ciconia nigra) is a strictly protected species, whose conservation efficiency depends on precise monitoring of abundance and reproductive success. We analysed its population dynamics in 1991–2020 by combining abundance data from various monitoring plots. We also analysed changes in reproductive parameters during the sam...

The black kite (Milvus migrans) is a rare breeder in Estonia (0–5 pairs; Elts et al. 2019), whose nests have been rarely found and detailed descriptions of its habitats are lacking. In the current study, I analysed ten nests from eigh breeding territories, found in Estonia in 2018–2021, at landscape, nest site and nest tree level. Landscape in 2 km...

The population of the Lesser and the Greater Spotted Eagles was monitored during 2000–2019 in the Southern part of the Berezinsky Biosphere Reserve. The total number of pairs remains relatively stable. However, the presence of mixed pairs was revealed, the number of which varies from year to year. In different years, from 6 to 10 pairs were recorde...

Dispersal and survival are important determinants of population dynamics and should be monitored in both threatened and recovered populations. We used colour ringing with a capture–mark–recapture approach to estimate the age distribution, survival and dispersal in a recently recovered Baltic Osprey Pandion haliaetus population. The mean age of bree...

The greater spotted eagle (Clanga clanga) is poorly known compared to other European eagles. We tracked an immature greater spotted eagle during 2018–2020 within the eastern European part of the species’ distribution, west of the Ural Mountains. Because so little is published about the annual movements of this species, especially from that region,...

The greater spotted eagle (Clanga clanga) is a flexible migrant raptor species exhibiting both short- and long-distance migration patterns. Its breeding range stretches across Eurasia from the Baltic Sea in the west to the Pacific Coast in the east; the winter distribution stretches along a wide belt across the entire southern Eurasia and extends t...

The Eurasian buzzard (Buteo buteo) is the one of the commonest Western Palaearctic raptors and an obligate soaring migrant avoiding crossing of large water surfaces. This flexible raptor species exhibits various migration strategies, which are largely attributed to subspecies. Westerly distributed Common buzzard B. b. buteo is partial, short-distan...

In this study, we aimed to characterize the population structure, drug resistance mechanisms, and virulence genes of Enterococcus isolates in Estonia. Sixty-one Enterococcus faecalis and 34 Enterococcus faecium isolates were collected between 2012 and 2014 across the country from various sites and sources, including farm animals and poultry ( n = 5...

Context Small woody features (SWF; tree lines and small woods) in agricultural landscapes provide a substitute for forest conditions for a wide range of species and a suitable edge habitat for ecotone species. The importance of SWF for biodiversity is usually inferred from presence or abundance data for small animals. Although large animals, due to...

The article provides information about the first records of the Greater Spotted Eagle (Clanga clanga) of the pale morph “fulvescens” in Belarus. In one case, an adult female was successfully breeding during two years 2018-2019 (Zhitkovichi district, Gomel region). In the second case, in 2019, in a brood of two chicks, one had a pale phenotype, and...

Habitat associations of small mammals are an essential component of ecosystem functioning. We studied habitat associations of small mammals over an 8-year period in a hemiboreal forest-farmland landscape. We observed all five rodents and one shrew species in meadows, three species in forests, and two species in crop fields. Total abundance was even...

Habitat associations of small mammals are an essential component of ecosystem functioning. We studied habitat associations of small mammals during an 8-year period in a hemiboreal forest–farmland landscape. We observed all five rodent and one shrew species in meadows, three species in forests, and two species in crop fields. Total abundance was eve...

Effective bioindicators of old-growth forest are important for conservation. The Greenish Warbler (Phylloscopus trochiloides viridanus), a forest-dwelling passerine, has been recorded in old-growth forests; however, its precise habitat preferences are poorly studied. We used opportunistic observations collected by citizen scientists and stand descr...

Animal home‐ranges are expressions of the biology and ecology of a species and their size is often considered a proxy for habitat quality. Understanding the factors affecting variation in home‐range size may aid prediction of the impact of local or global environmental change on studied populations. To this end, we established an international coll...

The majority of Common Cranes (Grus grus) breeding in northern Europe are short- to medium-distance migrants that overwinter in southern Europe, northern Africa, and the Middle East. However, some individuals migrate longer distances to as far as Ethiopia. Using data from 18 satellite-tracked juvenile Common Cranes, we assessed (1) the length and l...

Connectivity between golden eagle (Aquila chrysaetos) populations is poorly understood. Field studies exploring natal dispersal suggest that this raptor is a philopatric species, but with the ability to roam far. However, little is known about the population structure of the species in Europe. Our study is based on 14 microsatellite loci and is com...

Connectivity between golden eagle (Aquila chrysaetos) populations is poorly understood. Field studies exploring natal dispersal suggest that this raptor is a philopatric species, but with the ability to roam far. However, little is known about the population structure of the species in Europe. Our study is based on 14 microsatellite loci and is com...

Forest-dwelling raptors nest in the same close, mature forest stands over many years. As mature stands are targets for timber harvesting, the conservation of nest sites should be integrated into commercial forestry practices. Ecological data supporting conservation decisions are essential for ensuring effective conservation, and minimising costs an...

For more than half a century, the Western Eurasian Crane (Grus grus grus) has been expanding its range toward western Europe, recolonizing areas where it had been previously driven to extinction, including the UK, the Netherlands and Denmark. The Western Eurasian Crane is, on the one hand, a very mobile, migratory species, but on the other, is terr...

The current paper includes the new taxonomic list of Estonian breeding and wintering bird species and their abundance estimates. Up to 31.12.2018, the official list of Estonian birds contains 389 bird species (categories A–C) and in unofficial list additional 5 species to category D and 12 species to category E. Breeding has been confirmed in 233 s...

The aims of monitoring of diurnal and nocturnal raptors are: to collect and provide stakeholders with data on populations of threatened and protected raptor species, to follow the status of biodiversity at the ecosystem scale (notably at landscape scale), and to biomonitor environmental pollution. Here we present data on breeding densities and repr...

In species with sexual dimorphism, raising female or male offspring may be associated with different costs and benefits, resulting in a skewed nestling sex ratio. We examined the influence of: weather conditions, hatching date and brood size on nestling sex ratio in the black stork Ciconia nigra. We used molecular methods to determine the sex of 28...

High genetic diversity and low differentiation retained in the European fragmented and declining Greater Spotted Eagle (Clanga clanga) population Ülo Väli, Valery Dobrovski, Marina Dzmitranok, Grzegorz Maciorowski & Bernd-Ulrich Meyburg Characterising genetic diversity and structure of populations is essential for effective conservation of threa...

Characterising genetic diversity and structure of populations is essential for effective conservation of threatened species. The Greater Spotted Eagle (Clanga clanga), a large and globally vulnerable raptor, is extinct or in severe decline in most of its previous range in Europe. We assessed whether the remnants of European population are genetical...

Understanding the mechanisms forming species' ranges is a central ecological question, which could be answered by analysing factors limiting peripheral populations. In threatened species, such studies are essential for establishing effective conservation measures across the range. We analysed factors potentially influencing breeding in a declining...

Hybridization, the interbreeding of different species, plays an important role in several evolutionary processes but can have detrimental effects on the species involved, including extinction. We documented increased levels of hybridization between two Clanga species (Lesser-spotted Eagle C. pomarina and Greater Spotted Eagle C. clanga), following...

The osprey (Pandion haliaetus) is a species of conservation concern in Estonia. Research into its habitat use, in particular an up-to-date analysis of foraging habitats, has been specified in the national conservation action plan for the species. Here we analysed opportunistic bird observations, collected by citizen scientists in the period 2008–20...

Raptors are valuable indicators of biodiversity; monitoring of raptors aids detection of changes in ecosystem quality. In Estonia, populations of breeding raptors have been monitored for several decades but monitoring of wintering raptors started only in 2014. Here, I summarize the results of monitoring of wintering raptors in the period 2014–2018....

Belarusian greater spotted eagles (GSE) were wintering in two main regions: the Balkan Peninsula and Northeast Africa (the Nile River basin). Sex-related differences in the migratory strategy of GSE have been noted. Thus, all tagged females (n = 3) wintered on the Balkan Peninsula, and 80% of males in Africa (n = 5). The average length of the migr...

Questions Long‐term fragmentation and land use in Europe have created a landscape pattern where small forest patches are embedded among agricultural landscapes. These small forest patches can be one of the few habitats left to maintain the species richness and ecosystem functions within intensively managed agroecosystems. We ask, which factors dete...

Capsule: Transect-based common bird monitoring methods and opportunistic data from citizen scientists are not equal alternatives to mapping of raptors in study plots. Aims: To analyse the efficacy of common breeding and wintering bird monitoring schemes, as well as databases of casual bird observations, in providing population trends for raptors. M...

Proper timing of events in the annual cycle is essential for successful breeding in birds, especially in long-distance migrants. In this study, the phenology of the main breeding phases, including arrival at and departure from the nesting site, is reported for a Lesser Spotted Eagle population. Most data were gathered by 12 to 22 trail cameras annu...

Telemetric studies have provided ample information on threatened raptors, but still little is known about space use and dispersal of common species. Here I describe the home range and breeding dispersal of a GPS-tracked adult male common buzzard, studied in south-eastern Estonia in 2014–16. This buzzard’s home range covered 8.3 km² (kernel 95% esti...

Anthropogenic loss of biodiversity is often indicated by the disappearance of top predators. However, some of them have adapted to man-made agricultural landscapes. Among raptors, one such example is the Lesser Spotted Eagle. We compiled an exhaustive data set on foraging habitat composition of this species by direct field mapping and detailed land...

Capsule: In the migratory Lesser Spotted Eagle Clanga pomarina, colour rings and Global Positioning System transmitters indicated annual survival rates similar to other large raptors, but the rate suggested by wing-tags was significantly lower due to the higher rate of tag loss.

Montagu’s Harrier is a widespread raptor whose population trends and habitats have varied across Europe. The Estonian population was growing during the 20th century but has been stable over the last two decades. Now its size could be estimated at 200-400 pairs. Montagu’s Harrier is distributed all over the country with a mean density of 0.65 pairs...

We assessed whether populations of the migratory, philopatric, territorial Lesser Spotted Eagle Clanga pomarina are regulated through territoriality and density-dependent reproduction rates. In the north-western part of the distribution to the east of the Baltic Sea, territories were spaced regularly and consistently between years. We did not find...

We analysed migration strategies of the Osprey Pandion haliaetus on the poorly studied Eastern European– East African flyway. Four adult birds were equipped with GPS-based satellite-transmitters or data-loggers in their breeding sites in Estonia (north-eastern Europe) and tracked to their wintering grounds in Africa and back, during up to six migra...

The Common Buzzard (Buteo buteo) is the most numerous of Estonian breeding raptors; most of the population winters in Central Europe. Although its arrival and departure times are rather well monitored in Estonia, the published data on breeding phenology has remained as poorly described thus far. The aims of the current study was the assessment of t...

Habitat selection of birds varies spatially, but the scale of study determines whether differences are found or not. In the current study regional differences within Estonia were focused on. Habitat selection of the Common Buzzard (Buteo buteo) was analysed in southern Hiiumaa and the results were compared with those obtained earlier in Tartu Count...

We studied a sympatric and crossbreeding population of the Lesser and the Greater Spotted Eagle in the Biebrza Valley, NE Poland. In order to follow the dynamics of hybridisation and its possible causes we monitored these two species between 1996 and 2012, using visual and genetic species identification. Individuals in up to 51 territories annually...

The Common Buzzard Buteo buteo is a widespread species whose migration pattern differs by subspecies and regionally. Ring recoveries indicated that Buzzards originating from Estonia move southwest and winter in central and western Europe. This suggests that Estonia is occupied by the nominate subspecies of the Common Buzzard, which is a short-dista...

The contamination with DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) and its breakdown products as a potential cause of population decline of Black Stork has been studied in Latvia since 2008. In order to test if contamination is local or widely distributed we collected failed eggs from nests also in Estonia, Belarus, Poland, Czech Republic,...

Sex ratio is an indicator of population health as unexpected biases may indicate potential threats. We studied nestling sex ratio in Black Stork Ciconia nigra populations in order to check potential biases and differ-ences along east–west and north–south gradient across its distribution range in Europe. We also studied variation between years, and...

Population trends of the lesser and greater spotted eagle in Estonia were comparatively estimated using data obtained in 1994-2014 from the monitoring scheme of common raptors and from special plots for monitoring of spotted eagles. Both approaches had pros and cons, but resulted in similar population trends. The numbers of the lesser spotted eagle...

Knowing the winter behaviour is essential for deciding on conservation strategies for threatened migratory species such as the greater spotted eagle (Aquila clanga). Fidelity and inter-annual variation in winter home range of an Estonian greater spotted eagle were studied during the first four years of its life by means of GPS satellite telemetry i...

Selected medium-sized birds (grouse, feral pigeon, trushes and corvids) were mapped in 16 Estonian farmland study plots in winter 2013/14, resulting in population densities of ten species (table 1). Reasonable population estimates for Estonia were obtained for the magpie (8500 – 12000 wintering individuals), the hooded crow (28 000 – 46 000 individ...

In Estonia the raptors and owls have been rather well studied during the recent decades. However, the focus has mainly been on the breeding season, while the data on wintering birds of prey has been gathered only locally. In the current study we mapped birds of prey, and the great grey shrike (Lanius excubitor), in 13 farmland study plots in 2006 a...

The Goshawk Accipiter gentilis is a partially migrating raptor species, but its movement patterns differ between regions. In this study we have analysed ring recoveries of hawks ringed or recovered in Estonia (northeastern Europe) to identify the origin, direction and age structure of moving Goshawks. The vast majority of the foreign-ringed birds r...

We analysed 120 white-tailed sea eagles Haliaeetus albicilla from eastern (Poland and Estonia) and southeastern (Serbian Danube population) Europe for genetic variability and structuring at the mitochondrial control region and seven nuclear microsatellite loci. We combined this new dataset with sequence and genotype data from previous analyses cove...

Weather conditions and prey abundance impact many birds, but the influence differs between species and regions. I used 18-year data from Estonia, north-eastern Europe, in order to analyse the comparative effects of these factors on the breeding performance and nestling sex ratio in the Lesser Spotted Eagle. All studied reproductive parameters showe...

Recent theoretical and empirical work points toward a significant role for sex-chromosome linked genes in the evolution of traits that induce reproductive isolation and for traits that evolve under influence of sexual selection. Empirical studies including recently diverged (Pleistocene), short-lived avian species pairs with short generation times...

DNA sequence summary statistics for all loci included in the study. Summary statistics from the sequence data for 36 autosomal and 15 Z-chromosome linked genes. Chr = chromosome (in chicken), Gene = gene name for the ortholog in chicken or, when no data were at hand for chicken, for another vertebrate species, A. cla = Aquila clanga (greater spotte...

Greater Spotted Eagle Aquila clanga and Lesser Spotted Eagle Aquila pomarina are hybridising Eurasian raptors, but our knowledge of hybrid fertility is poor. Here, I present a case of interbreeding between a F1 hybrid spotted eagle male and a Lesser Spotted Eagle female in Estonia. The hybrid was first studied and ringed as a nestling in 1999, show...

Spotted eagles include two medium-sized similar raptors breeding sympatrically in Estonia. In the current study I checked if population numbers derived from country-wide field observations over a 20-year period were in line with the estimate extrapolated from surveys in study plots (500–600 breeding territories of the Lesser Spotted Eagle and 10–30...

Hybridization is a significant threat for endangered species and could potentially even lead to their extinction. This concern applies to the globally vulnerable Greater Spotted Eagle Aquila clanga, a species that co-occurs, and potentially interbreeds, with the more common Lesser Spotted Eagle Aquila pomarina in a vast area of Eastern Europe. We a...

The correct identification of hybrids is essential in avian hybridisation studies, but selection of the appropriate set of genetic markers for this purpose is at times complicated. Microsatellites and single nucleotide polymorphisms (SNPs) are currently the most commonly used markers in this field. We compare the efficiency of these two marker type...

Microsatellite variability is widely used to infer levels of genetic diversity in natural populations. However, the ascertainment bias caused by typically selecting only the most polymorphic markers in the genome may lead to reduced sensitivity for judging genome-wide levels of genetic diversity. To test this potential limitation of microsatellite-...

We introduce the use of short insertion-deletion polymorphisms (indels) for genetic analysis of natural populations. Sequence reads from light shot-gun sequencing efforts of different dog breeds were aligned to the dog genome reference sequence and gaps corresponding to indels were identified. One hundred candidate markers (4-bp indels) were select...