In order to get full understanding of how evolution proceeds in natural settings it is necessary to reveal the genetic basis of the phenotypic traits that play a role for individual fitness in different environments. There are a few possible approaches, most of which stem from traditional mapping efforts in domestic animals and other model species. Here we set the stage for gene mapping in natural populations of birds by producing a large number of anchor markers of broad utility for avian genetical research and use these markers to generate a genetic map of the collared flycatcher (Ficedula albicollis). The map reveals a very high degree of synteny and gene order conservation between bird species separated by as much as 100 million years. This is encouraging for later stages of mapping procedures in natural populations since this means that there is a possibility to use the information from already characterized avian genomes to track candidate genes for detailed analysis in non-model species. One interesting aspect of the low degree of rearrangements occurring in the avian genomes is that this could play a role in the low rate of hybridization barriers formed in birds compared to for instance mammals. An analysis of Z-linked gene markers reveals relatively long-range linkage disequilibrium (LD) in collared flycatchers compared to other outbred species but still, LD seems to decay within < 50 kb indicating that > 20.000 markers would be needed to cover the genome in an association scan. A detailed scan of 74 Z-linked genes evenly distributed along the chromosome in both the collared flycatcher and the pied flycatcher (Ficedula hypoleuca) indicates that there are regions that evolve under directional selection, regions that might harbor loci of importance for adaptive divergence and/or hybrid inviability.

Parental care can be important especially in passerine birds and can depend on environment, food availability and behaviour. A behaviour that can affect the food supply for the offspring is neophobia, the fear of novel objects. The more fear the bird exhibits the less it visits the nest with food. In my study I aimed to examine neophobia and how it differed based on sex and if offspring number and weight influenced the behaviour. Video recordings of collared flycatchers nest boxes were used to see how the behaviour differed by placing a novel object on the nest box. The behaviours tested were duration of perching, hovering and visit including latency and frequency of visit. The results showed that there was a significant difference between the sexes in duration, latency, and frequency of visit but also duration of perching before and after placing a novel object on the nest box. In addition, my results showed that nestling weight significantly influenced frequency of visit and nestling number influenced duration of visit. The study shows that the collared flycatchers do express neophobia differently based on the sex and the nestling’s weight and number. Future studies could investigate if neophobia is a plastic behaviour and the effects of prolonged exposure to novel objects whichcould change the offspring’s survival chances or even the nestling’s behaviour.

This thesis investigates the ecological and evolutionary implications of a recent secondary contact between two closely related bird species: collared (Ficedula albicollis) and pied (F. hypoleuca) flycatchers. Collared flycatchers started to colonize the Swedish island of Öland, where pied flycatchers were already present, in the late 1950s-early1960s. My major aims were to investigate which factors are acting against versus for long-term coexistence between the two species. Specifically, I investigated the relative importance of allopatric divergence, interspecific competition, hybridization and learning in promoting or inhibiting coexistence. The combined effects of interspecific competition and hybridization drives pied flycatchers towards local extinction in their preferred deciduous habitat. However, my results also show that pied flycatchers are better able to tolerate harsh environmental conditions. This trade-off between competitive ability and resilience in the face of harsh conditions facilitates a regional coexistence between the species. Coexistence is furthermore favoured by competition-mediated divergence in breeding habitat choice, timing of breeding and male breeding plumage colouration. Due to interspecific competition, male pied flycatchers are forced to breed in a more mixed forest type with a later peak in food abundance, which is accompanied by a divergence in breeding time between the two species. In areas shared with collared flycatchers, male pied flycatchers with brown plumage coloration, most divergent from that of collared flycatchers, are favoured by selection. In addition to facilitating coexistence, the observed shift in habitat occupancy increases reproductive isolation between the two species. By using cross-fostering experiments I demonstrate that natal habitat imprinting has the potential to additionally speed up habitat segregation. Finally I show that hybrid nestlings express an intermediate response to harsh environments, indicating that another aspect of ecological-based selection may be important in reproductive isolation between the species. In summary, my results show that adaptations during historic allopatry are important both in facilitating coexistence as well as in providing a foundation for further ecological divergence at secondary contact. This is of relevance today as many species are shifting their distributions in response to habitat disturbance and global warming.

Individuals vary from each other in their genetic content. Genetic diversity is at the core of the evolutionary theory. Rooted in a solid theoretical framework developed as early as the 1930s, current empirical observations of genomic diversity became possible due to technological advances. These measurements, originally based on a few gene sequences from several individuals, are becoming possible at the genome scale for entire populations. We can now explore how evolutionary forces shape diversity levels along different parts of the genome. In this thesis, I focus on the variation in levels of diversity within genomes using avian systems and in particular that of the collared flycatcher (Ficedula albicollis). First, I describe the variation in genetic diversity along the genome of the collared flycatcher and compare it to the amount of variation in diversity across individuals within the population. I provide guidelines on how a small number of makers can capture the extent of variability in a population. Second, I investigate the stability of the local levels of diversity in the genome across evolutionary time scales by comparing collared flycatcher to the hooded crow (Corvus (corone) corone). Third, I study how selection can maintain variation through pervasive evolutionary conflict between sexes. Lastly, I explore how shifts in genome-wide variant frequencies across few generations can be utilised to estimate the effective size of population.

La dispersion est un trait d'histoire de vie clé pour les processus écologiques et évolutifs dans les populations naturelles. Les dernières recherches se sont notamment focalisées sur les corrélations entre traits comportementaux et la dispersion, ceci afin de mettre en évidence des syndromes comportementaux de dispersion, tout en démontrant la base génétique de la dispersion. Les dispersants ne seraient donc pas une part aléatoire d'une population, mais des individus montrant des stratégies particulières qui augmenteraient leur chances de succès. Cette thèse s'est orientée vers trois objectifs de recherche majeurs. Le premier est la mise en évidence d'une base génétique de la probabilité de disperser dans une population fragmentée de gobe-mouches à collier Ficedula albicollis. Les résultats nous ont montré, au-delà de l'estimation de la base génétique de la dispersion, une distribution spatiale non aléatoire de l'apparentement dans cette population, qui pourrait être dû à des effets génétiques sur les règles de décision de choix de l'habitat. Le deuxième s'intéresse à la corrélation phénotypique et génétique entre le comportement de dispersion natale et le comportement de défense du nid, chez le martinet alpin Tachymarpis melba. Nous avons montré que la dispersion natale et le comportement de défense du nid sont négativement corrélés au niveau phénotypique mais aussi génétique dans ces populations. Enfin, le troisième nous à conduit à tester l'existence de syndromes comportementaux de dispersion, c'est-à-dire si les dispersants présentent un profil comportemental particulier, leur permettant en particulier de coloniser de nouveaux sites, chez le gobe-mouche à collier / Dispersal is a key like history trait for ecological and evolutionary processes in wild population. The last researching particularly focused on the correlation between behavioural trait and dispersal, in order to emphasize the existence of behavioural syndromes of dispersal, and on the estimation of the genetic basis of the dispersal behaviour. Dispersant individuals could not be a random part of the population, but individuals showing particular strategies, that help them to succeed in their dispersal attempt. This thesis has three main aims of research. The first is to show a genetic basis of the dispersal propensity in a fragmented population of collared flycatchers (Ficedulla albicollis). We shown not only the genetic bases of the dispersal, but also a non-random spatial distribution of relationship between individuals in this population, that might be due to genetic effects on the decision rules of habitat choice in this population. The second aim concerns phenotypic and genetic correlation between the natal dispersal and a behavioural trait, the nest-defense behaviour, in the alpin swift (Tachymarpis melba). We shown that natal dispersal and nest-defense behaviour are negatively correlated at a phenotypic level, but also at a genetic level in theses populations. Finally, the third aim attempt to test the existence of behavioural syndrome of dispersal, that is if dispersant individuals have a particular behavioural profile, which enable them to colonize new sites, in the collared flycatcher

La dispersion est définie comme le mouvement d'un individu entre le site de naissance et le premier site de reproduction ou entre deux sites de reproduction. La dispersion se traduit par des échanges d'individus et des flux de gènes entre les populations et est donc reconnue comme un trait d'histoire de vie clé de part son rôle déterminant sur de nombreux processus écologiques et évolutifs comme la dynamique ou la génétique des population, la répartition spatiale des espèces ou encore la capacité des espèces à faire face aux changements brutaux induits par les activités humaines. Pourtant les conséquences de la dispersion en terme de valeur sélective individuelle restent mal connues malgré leur importance dans l'évolution de la dispersion. Le but de cette thèse est d'identifier plus précisément les conséquences de la dispersion en terme de valeur sélective individuelle en utilisant à la fois des approches corrélative et expérimentale dans une population sauvage de passereaux migrateurs, le gobe mouche à collier (Ficedula albicollis). Grâce à des données à long terme comprenant plus de 20 ans de suivi, des différences entre les individus dispersants et philopatriques ont pu être mises en évidence à la fois à l'échelle de la vie des individus et à l'échelle annuelle, celle de l'événement de reproduction. Les résultats mettent en évidence des effets de la dispersion dépendant à la fois des conditions et du phénotype des individus et soulignent donc le fait que la balance entre les coûts et les bénéfices est le résultat d'interactions subtiles entre l'environnement et les caractéristiques de l'individu. D'autre part, l'expérience de dispersion forcée a permis de démontrer clairement l'existence de coûts liés à l'établissement dans un environnement non familier que seuls certains individus sont capables de surmonter. Enfin, l'absence de différence dans les décisions majeures de reproduction une fois les individus établis, suggère que la dispersion doit majoritairement être adaptative, une fois les coûts de l'installation surmontés / Dispersal is commonly defined as the movement of an individual from its natal or previous breeding site to a new breeding site. Because dispersal involves movements of individuals and genes among populations, it is widely recognized as a key life history trait with strong effects on many ecological and evolutionary processes, such as population dynamics and genetics but also species spatial distribution or response to brutal environmental variations induced by human activities. Yet, the consequences of dispersal in terms of individual fitness remain poorly understood despite their crucial importance in the understanding of the evolution of dispersal. The aim of this PhD is to get better insights in the fitness consequences of dispersal using both correlative and experimental approaches at different scales, i.e. annual and lifetime scales, in a wild patchy population of migratory passerine bird, the collared flycatcher (Ficedula albicollis). Using a long term data set encompasses more than 20 years of data, differences between dispersing and philopatric individuals were showed both at a lifetime and annual scale. The results highlighted strong phenotypic- and condition-dependent effects of dispersal and underline that the balance between the costs and benefits of dispersal is likely to be the result of subtle interactions between environmental factors and individuals’ phenotype. Moreover, the experiment of forced dispersal demonstrated that dispersal might entail costs linked with settlement in a new habitat, which only some individuals may overcome. Nevertheless, the absence of difference in major fitness related decisions after settlement suggests that dispersal is mostly adaptive for individuals overcome such costs

Climate change is affecting the distribution of species, sometimes making previously separated species come into secondary contact. For closely related species, this often leads to competition and sometimes also hybridization, which can have negative effects on genetic bio? diversity. Collared flycatcher (Ficedula albicollis) and pied flycatcher (Ficedula hypoleuca) are two closely related species that hybridize where they meet on the Swedish islands Gotland and Öland. Studies from Gotland and the north of Öland have shown that the pied flycatcher is outcompeted and displaced from favourable, high-quality habitat by the collared flycatcher, leading to a decrease in the number of pied flycatchers in deciduous forest. However, this has not been shown for the ecologically important and one of the largest deciduous forests in Sweden, the Mittland forest located in central Öland. Here I use census data collected during two periods separated by 37 years from the Mittland forest to investigate habitat choice and competition between the two species. Although the number of collared flycatcher has greatly increased in the area, I show that the collared flycatcher has not outcompeted the pied flycatcher from favourable habitat. I also show that pied flycatcher does not have a preference for coniferous forest. Lastly, I show that the two species have a near complete overlap of habitat niches. These results indicate that they are in direct competition over the favourable habitat, that there is no equilibrium between the species and the collared flycatcher might still be expanding in the Mittland forest. Allowing more time to pass and further research will show if the pied flycatcher will be displaced from the high-quality habitats in this area or not.

Dispersal is a key life history trait for ecological and evolutionary processes in wild populations. The latest research has particularly focused on the correlation between behavioural traits and dispersal, in order to emphasize the existence of behavioural syndromes of dispersal, and on the estimation of the genetic basis of the dispersal behaviour. Dispersing individuals are not a random part of the population, but are individuals showing particular strategies, that help them to succeed in their dispersal attempt. This thesis has three main aims of research. The first is to show a genetic basis of the dispersal propensity in a fragmented population of collared flycatchers (Ficedulla albicollis). We show, not only, the genetic bases of the dispersal, but also a non-random spatial distribution of relationship between individuals in this population, that might be due to genetic effects on the decision rules of habitat choice in this population. The second aim concerns phenotypic and a genetic correlation between the natal dispersal and a behavioural trait, the nest-defense behaviour, in the alpin swift (Tachymarptis melba). We showed that natal dispersal and nest-defense behaviour were negatively correlated at a phenotypic level, but also at a genetic level in these populations. Finally, the third aim attempts to test the existence of a behavioural syndrome of dispersal, that is if dispersing individuals have a particular behavioural profile, which enable them to colonize new sites, in the collared flycatcher. / <p>The exmination will be videolinked to seminar room 1003 Evolutionary Biology Centre, EBC, Uppsala University.</p>

Age is often a neglected factor in ecological studies. However, age-related changes in reproduction and survival of organisms may strongly influence population dynamics. The Gotlandic population of collared flycatchers is a perfect system for studying age-related changes in the wild, as the exact age and reproductive history of most individuals is known. Collared flycatchers (Ficedula albicollis) on Gotland show the typical pattern of age-related changes in survival and reproductive success; both factors show an increase early in life and a decrease late in life. This thesis presents a broad study not only of age-related patterns of reproduction and immunity, but also proposes the mechanisms driving these patterns. My results show that in addition to survival probability and reproductive performance, reproductive costs and life-history trade-offs also change with progressing age. There is a significant increase in reproductive performance at the population level during first years of life which result from selection against low quality phenotypes. On the individual level this pattern is best explained by an optimization of reproductive effort. However, high quality individuals have higher reproductive success as early as their first breeding event and are long-lived. Thus, they seem to adopt a different strategy than lower quality, short-lived individuals. Differences in individual quality seem to be shaped by the developmental conditions experienced as nestlings. Fledglings with longer tarsi, but lower body mass become long-lived, high quality adults. Young individuals breeding for first time pay higher costs of reproduction. They also express a limited ability to reduce these costs by breeding in high quality territories when compared to middle-aged individuals. Young individuals seem to invest more into self-maintenance, whereas old individuals reduce the level of self-maintenance (measured as immune response) and redistribute their investment towards reproduction. Thus, old individuals are limited in their ability to reduce reproductive costs under favorable conditions, especially as they also senesce, which pattern is also shaped by individual quality. Variation in individual quality appears to have an strong effect on age-related survival probability, reproductive performance, reproductive costs, and even life-history decisions. Therefore, taking this factor into account in studies of life-history patterns is necessary to obtain reliable results.

Abstract Animals need information about local conditions to make optimal fitness-enhancing decisions such as where to breed. Information can be acquired by personal sampling of the environment, but it can also be acquired from other individuals. The latter is termed social information use. Social information use has gained a lot of attention in modern ecology because it affects principal ecological phenomena such as animal distribution and resource use. Social information use is not restricted to obviously cognitive mammals and birds but is also found in e.g. reptiles, fish and insects. Social information use studies have thus far been concentrated on situations with one social information user and one (often the same) source species. The community-wide consequences of social information use have almost exclusively been considered in theoretical studies. In this thesis, I studied empirically social information use in the nest site selection within and between species in a cavity-nesting bird community consisting of the collared flycatcher (Ficedula albicollis), the great tit (Parus major) and the blue tit (P. caeruleus). I studied social information use on two time scales: social information gathered just before a breeding attempt, and social information gathered already during the previous breeding season for the following year’s breeding attempt. I used experiments in which different white geometric symbols represented nest site choices of earlier settled tutors and empty nest boxes, and I observed the symbol choices of later-breeding individuals. The symbol approach eradicates bias from innate and learned preferences enabling strong inference. My results demonstrate that collared flycatchers use social information from both con- and heterospecific tutors in different situations in a flexible manner. Hence, social information use seems to be context-dependent. Furthermore, I show that great tits avoid choosing nest site characteristics which were associated with either con- or heterospecifics nests the previous year and prefer symbols which depicted an empty nest box the previous year, probably to avoid nest ectoparasites. I also show that in great tits the male has greater influence on nest site selection than previously assumed even though the female builds the nest. My thesis deepens our understanding about the complexity of social information use and highlights its significance in future ecological research. / Tiivistelmä Eläimet tarvitsevat informaatiota paikallisista olosuhteista tehdäkseen edullisia päätöksiä esimerkiksi siitä, missä lisääntyä. Informaatiota voidaan hankkia tutkimalla ympäristöä itse, mutta sitä voidaan hankkia myös muilta yksilöiltä. Jälkimmäistä kutsutaan sosiaaliseksi informaatioksi. Eläinten sosiaalisen informaation käyttö on saavuttanut viime aikoina paljon huomiota ekologisessa tutkimuksessa, koska se vaikuttaa tärkeisiin ekologisiin ilmiöihin, kuten eläinten levinneisyyteen ja resurssien käyttöön. Sosiaalinen informaation käyttö ei rajoitu vain nisäkkäisiin ja lintuihin, vaan sitä on havaittu myös esimerkiksi matelijoilla, kaloilla ja hyönteisillä. Sosiaalisen informaation käyttöä on tutkittu lähes yksinomaan lajien sisällä tai käyttäen ainoastaan yhtä sosiaalisen informaation lähdelajia. Yhteisötason vaikutuksia on pohdittu miltei pelkästään teoreettisissa tutkimuksissa. Tässä väitöskirjatyössä tutkin kokeellisesti sosiaalisen informaation käyttöä pesäpaikan valinnassa lajin sisällä ja lajien välillä kolopesivien lintujen yhteisössä sepelsiepolla (Ficedula albicollis), talitiaisella (Parus major) ja sinitiaisella (P. caeruleus). Otin tutkimuksissani huomioon kaksi aikatasoa: tutkin juuri ennen pesimisyritystä kerätyn sekä jo edellisen lisääntymiskauden aikana seuraavan vuoden pesintää varten hankitun sosiaalisen informaation käyttöä. Kokeissani käytin linnunpönttöihin kiinnitettyjä erilaisia valkoisia geometrisia symboleita, jotka edustivat aiemmin pesinnän aloittaneiden lintujen eli tuutoreiden pesäpaikanvalintoja. Seurasin tämän jälkeen myöhemmin pesimään saapuvien parien symbolivalintoja. Tulosteni perusteella sepelsiepot hankkivat sosiaalista informaatiota sekä lajitovereiltaan että tiaisilta joustavasti eri tilanteissa. Lisäksi osoitan, että talitiaiset välttävät valitsemasta pesäpaikkoja, jotka olivat asuttuina edellisenä vuonna, ja suosivat sellaisia pesäpaikkoja, joissa ei pesitty edellisenä vuonna - todennäköisesti välttääkseen kirppuja ja muita pesäloisia. Osoitan myös, että talitiaiskoirailla on suurempi vaikutus pesäpaikan valintaan kuin aikaisemmin on oletettu, vaikka naaraat rakentavat pesän. Väitöskirjatyöni syventää käsitystämme sosiaalisen informaation käytön monitahoisuudesta eläinkunnassa ja korostaa sen merkitystä ekologisessa tutkimuksessa.