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Martin Walter Seltmann Martin Martin W. | Seltmann Of milquetoasts and daredevils – Personalities in female eiders

This thesis describes how the life-history trade-off between survival and fecundity in female eiders (Somate- ria mollissima) could be resolved depending on consistent individual differences in escape behaviour, stress – Personalities in female eiders daredevils and milquetoasts Of physiology, individual quality and nest-site selection. It Martin Walter Seltmann demonstrates that these differences, termed personalities and stress coping strategies, are persistent individual characteristics with measurable effects on fitness. It suggests that these traits are subject to natural se- Of milquetoasts and daredevils lection and thereby can evolve. Furthermore, this thesis demonstrates that individual differences in stress phy- – Personalities in female eiders siology are related to individual quality in female eiders.

The Author Martin graduated from Stiftland Gymnasium Tirschen- reuth in 2001. He received his Master of Science degree in Ecology and Organismic Biology from University of Bayreuth in 2008. Since 2009, he has been working as a PhD student in the eider research group in the Aro- nia Coastal Zone Research Team, Åbo Akademi & Novia University of Applied Sciences. | 2014

9 789521 229923

Martin Walter Seltmann

Environmental and Marine Biology Department of Biosciences Åbo Akademi University Åbo, Finland, 2014

Supervisor Markus Öst ARONIA Coastal Zone Research Team Åbo Akademi University & Novia University of Applied Sciences Raseborgsvägen 9 10600 Ekenäs, Finland Co-supervisor Kim Jaatinen ARONIA Coastal Zone Research Team Åbo Akademi University & Novia University of Applied Sciences Raseborgsvägen 9 10600 Ekenäs, Finland Reviewer Hannu Pöysä Finnish Game and Fisheries Research Institute Yliopistokatu 6 80100 Joensuu, Finland Reviewer Kees van Oers Department of Animal Ecology Netherlands Institute of Ecology Droevendaalsesteeg 10 6708 PB Wageningen, The Netherlands Opponent Niels J. Dingemanse Department of Biology II Ludwig Maximilians University Großhaderner Str. 2 82152 Planegg-Martinsried, Germany Author’s address ARONIA Coastal Zone Research Team Åbo Akademi University & Novia University of Applied Sciences Raseborgsvägen 9 10600 Ekenäs, Finland [email protected]

“…gackgackgackgackgackgack…”

44101 Abstract

Traditionally biologists have often considered individual differences in behaviour or physiology as a nuisance when investigating a population of individuals. These differences have mostly been dismissed as measurement errors or as non-adaptive variation around an adaptive population mean. Recent research, however, challenges this view. While long acknowledged in human personality studies, the importance of individual variation has recently entered into ecological and evolutionary studies in the form of animal personality. The concept of animal personality focuses on consistent differences within and between individuals in behavioural and physiological traits across time and contexts and its ecological and evolutionary consequences. Nevertheless, a satisfactory explanation for the existence of personality is still lacking. Although there is a growing number of explanatory theoretical models, there is still a lack of empirical studies on wild populations showing how traditional life-history trade- offs can explain the maintenance of variation in personality traits. In this thesis, I first investigate the validity of variation in allostatic load or baseline corticosterone (CORT) concentrations as a measure for differences in individual quality. The association between CORT and quality has recently been summarised under the “CORT-fitness hypothesis”, which states that a general negative relationship between baseline CORT and fitness exists. I then continue to apply the concept of animal personality to depict how the life-history trade-off between survival and fecundity is mediated in incubating female eiders (Somateria mollissima), thereby maintaining variation in behaviour and physiology. To this end, I investigated breeding female eiders from a wild population that breeds in the archipelago around Tvärminne Zoological Station, SW Finland. The field data used was collected from 2008 to 2012. The overall aim of the thesis was to show how differences in personality and stress responsiveness are linked to a life-history context. In the four chapters I ex- amine how the life-history trade-off between survival and fecundity could be resolved depending on consistent individual differences in escape behaviour, stress physiology, individual quality and nest-site selection. First, I corroborated the validity of the “CORT-fitness hypothesis”, by showing that reproductive success is generally negatively correlated with serum and faecal baseline CORT levels. The association between individual quality and baseline CORT is, however, context dependent. Poor body condition was associated with elevated serum baseline CORT only in older breeders, while a larger reproductive investment (clutch mass) was associated with elevated serum baseline CORT among females breeding late in the season. Interestingly, good body condition was associated with elevated faecal baseline CORT levels in late breeders. High faecal baseline CORT levels were positively related to high baseline body temperature, and breeders in poor condition showed an elevated baseline body temperature, but only on open islands. The relationship between stress physiology and individual quality is modulated by breeding experience and breeding phenology. Consequently, the context dependency highlights that this relationship has to be interpreted cautiously. Additionally, I verified if stress responsiveness is related to risk-taking behaviour. Females who took fewer risks (longer flight initiation distance) showed a stronger stress response (measured as an increase in CORT concentration after capture and handling of the bird). However, this association was modulated by breeding experience and body condition, with young breeders and those in poor body condition showing the strongest relationship between risk- taking and stress responsiveness. Shy females (longer flight initiation distance) also incubated their clutch for a shorter time. Additionally, I demonstrated that stress responsiveness and predation risk interact with maternal investment and reproductive success. Under high risk of predation, females that incubated a larger clutch showed a stronger stress response. Surprisingly, these females also exhibited higher reproductive success than females with a weaker stress response. Again, these context dependent results suggest that the relationship between stress responsiveness and risk-taking behaviour should not be studied in isolation from individual quality and that stress responsiveness may show adaptive plasticity when individuals are exposed to different predation regi- mes. Finally, female risk-taking behaviour and stress coping styles were also related to nest-site choice. Less stress responsive females more frequently occupied nests with greater coverage that were farther away from the shoreline. Females nesting in nests with medium cover and farther from the shoreline had higher reproductive success. These results suggest that different personality types are distributed non-randomly in space. In this thesis I was able to demonstrate that personalities and stress coping strategies are persistent individual characteristics, which express measurable effects on fitness. This suggests that those traits are exposed to natural selection and thereby can evolve. Furthermore, individual variation in personality and stress coping strategy is linked to the alternative ways in which animals resolve essential life-history trade-offs. Sammanfattning (abstract in Swedish)

Biologer har traditionellt ansett individuell variation vara ett gissel då man vill undersöka en population av individer. Dessa skillnader har avfärdats an- tingen som mätfel eller som maladaptiv variation som omger populationens adaptiva medeltal. Nyare forskningsrön har utmanat denna uppfattning. Inom den mänskliga personlighetsforskningen har betydelsen av individuell variation erkänts sedan länge, men det är först nyligen som dess betydelse har uppmärksammats inom ekologiska och evolutionära studier i form av begreppet djurpersonlighet. Begreppet syftar på konsekventa skillnader i individers beteendemässiga och fysiologiska egenskaper som är stabila över tid och sam- manhang och som kan ha viktiga ekologiska och evolutionära konsekvenser. Ännu saknas dock en tillfredsställande förklaring till uppkomsten av personlighet. Trots att det finns allt flera teoretiska förklaringsmodeller råder det fort- farande en brist på empiriska studier i naturpopulationer som undersökt ifall resursallokeringskonflikter mellan livshistoriefunktioner kunde förklara uppkomsten av personlighetsvariation. I denna avhandling undersöker jag först ifall den allostatistiska belastnin- gen, d.v.s. variation i grundnivån av stresshormonet kortikosteron, utgör ett mått på individens kvalitet. Den s.k. ”kortikosteron-fitness hypotesen” gör gäl- lande att sambandet mellan grundnivån av kortikosteron och fitness förväntas vara negativt. I avhandlingens senare del tillämpar jag begreppet djurpersonlighet för att förklara hur ruvande ejderhonor (ådor) (Somateria mollissima) löser resursallokeringskonflikten mellan överlevnad och fekunditet, och hur ådornas individuella avvägningar avspeglas i variation i beteende och fysiolo- gi. För detta ändamål undersökte jag häckande ådor från en population i närhe- ten av Tvärminne zoologiska station i sydvästra Finland. Fältdatat insamlades mellan åren 2008 och 2012. Avhandlingens huvudsakliga målsättning var att visa hur individuella skillnader i personlighet och stressrespons är kopplade till livhistoriestrategier. I avhandlingens fyra delarbeten undersöker jag hur resursallokeringskonflikten mellan överlevnad och fekunditet kan lösas utgående från konsekventa individuella skillnader i flyktbeteende, stressfysiologi, individuell kvalitet och boplatsval. I mitt första arbete kunde jag bekräfta ”kortikosteron-fitness hypotesen”, eftersom individer med höga grundnivåer av kortikosteron i serum och ex- krementer i allmänhet hade lägre häckningsframgång. Däremot visade det sig att sambandet mellan individuell kvalitet och grundnivån av kortikosteron är starkt beroende av sammanhanget. Låg kroppskondition var förknippat med försämrad häckningsframgång bara bland äldre häckare, medan en större sats- ning på förökningen (kullvikt) var förknippad med förhöjda kortikosteronhalter i serum bland ådor som häckade sent på säsongen. Bland dessa sena häckare uppvisade ådor i bra kroppskondition förhöjda kortikosteronhalter i exkrementerna. Höga grundnivåer av kortikosteron i exkrementerna var också associerat med en förhöjd kroppstemperatur under ruvningen, och ådor i dålig kroppskondition uppvisade en högre kroppstemperatur, men denna effekt kunde bara upptäckas på öppna häckningsholmar. Sambandet mellan stressfysiologi och individuell kvalitet beror alltså på häckningserfarenhet och häckningsfenologi och man bör därför vara försiktig med hur man tolkar sambandet. Jag kunde också konstatera att stressresponsen är förknippad med individens risktagningsbenägenhet i närvaro av predatorer. Ådor som tog mindre ris- ker (längre flyktavstånd från boet) uppvisade en högre stressrespons, mätt som ökningen av kortikosteronhalt i serum efter att vi fångat och behandlat fågeln. Detta samband var dock beroende av ådans häckningserfarenhet och kroppskondition, så att unga häckare och häckare i dålig kondition uppvisade det starkaste sambandet mellan risktagning och stressrespons. Skygga ådor (längre flyktavstånd) hade också en kortare ruvningstid. Jag visade också att graden av stressrespons och predationsrisken växelverkade med moderns förökningssat- sning och förökningsframgång. Under år då predationsrisken var hög, uppvisade ådor med en större kull en högre stressrespons. Oväntat nog hade dessa ådor också bättre häckningsframgång under dessa farliga förhållanden. Mina resultat visar igen att sambandet mellan stressrespons och risktagningsbeteende formas av förhållandena och att sambandet därför inte bör studeras i isolation från individuell kvalitet, och att stressresponsen kan uppvisa adaptiv plasticitet då predationsrisken varierar. Ådans risktagingsbenägenhet och stresshanteringsstrategi hade också ett samband med boplatsvalet. Ådor med lägre stressrespons häckade i bon som var mer skyddade för insyn av vegetation och i bon som befann sig lägre bort från strandlinjen. Kläckningsframgången var störst i bon som hade en interme- diär täckningsgrad och kläckningsframgången var desto större ju längre bort från stranden boet befann sig. Dessa resultat antyder att den spatiella fördelnin- gen av olika personlighetstyper inte är slumpmässig. I denna avhandling kunde jag påvisa att personligheter och stresshanteringsstrategier är stabila individuella egenskaper som har mätbara effekter på fitness. Det här antyder i sin tur att dessa egenskaper är föremål för naturligt urval och kan därför formas av evolutionen. Jag kunde också visa att individuell variation i personligheter och stresshanteringsstrategier är förknippad med de alternativa sätt på vilka djur kan lösa grundläggande livshistorieallokerings- konflikter. Contents

List of original papers 1. Introduction ...... 11 1.1 What exactly is animal personality? ...... 12 1.2 Ultimate explanations for the existence of consistent individual variation ...... 12 1.3 Proximate mechanisms of consistent individual variation ...... 14 2. Aim of the thesis ...... 17 3. Materials and methods ...... 19 3.1 Study species ...... 19 3.2 Study area ...... 19 3.3 Field methods ...... 19 3.4 Laboratory methods ...... 19 3.5 Data analyses ...... 20 4. Main results and discussion ...... 23 4.1 Female stress coping profiles and nest characteristics are repeatable ...... 23 4.2 Baseline CORT as a context-dependent correlate of individual quality and fitness ...... 27 4.3 Link between stress responsiveness and boldness is dependent on individual quality ...... 29 4.4 Links between stress responsiveness, maternal investment and fitness are shaped by predation risk ...... 32 4.5 Nest-site characteristics are associated with coping style and have fitness consequences ...... 34 5. General conclusions and future directions ...... 36 5.1 Unresolved issues ...... 36 5.2 Future directions ...... 37 5.3 Concluding remarks ...... 39 6. Acknowledgements ...... 41 7. Literature cited ...... 43 Original papers Chapter I ...... 57 Chapter II ...... 67 Chapter III ...... 77 Chapter IV ...... 91 Personalities in female eiders 9

List of original papers

This thesis is based on the following papers, which will be referred to in the text by their Roman numerals:

I Jaatinen, K., Seltmann, M.W., Hollmén, T., Atkinson, S., Mash burn, K. & Öst, M. 2013. Context dependency of baseline glucocorticoids as indicators of individual quality in a capital breeder. General and Comparative Endocrinology, 191, 231–238.

II Seltmann, M.W., Öst, M., Jaatinen, K., Atkinson, S., Mashburn, K. & Hollmén, T. 2012. Stress responsiveness, age and body condition interactively affect flight initiation distance in breeding female eiders. Animal Behaviour, 84, 889–896.

III Jaatinen, K., Seltmann, M.W. & Öst, M. Context-dependent stress responses and their fitness consequences in a landscape of fear. Manuscript.

IV Seltmann, M.W., Jaatinen, K., Steele, B.B. & Öst, M. 2014. Boldness and stress responsiveness as drivers of nest-site selection in a ground- nesting bird. Ethology, 119, 1–13.

The original papers have been reprinted with the kind permission of El- sevier (paper I and II) and John Wiley and Sons (paper IV). 10 M.W. Seltmann Personalities in female eiders 11

1. Introduction good practice to focus on differences between genera and higher level taxa. Speaking about wild animals having Since then there has been a slow shift personalities frequently creates con- in approaching adaptive variation in fusion and misgivings among the ge- behaviour, with first comparing diffe- neral public, sometimes even among rences between species and then lo- biologists. On the other hand, pet cally adapted populations of the same owners or people that work intensi- species. Only recently has there been vely with domesticated animals will a call for taking this development one happily tell you that those animals do step further by looking at adaptive show distinct behavioural patterns. individual differences of traits within However, it has been scientifically single populations (Wilson 1998, demonstrated that wild animals also Dall et al. 2004). Many behavioural possess distinct behavioural patterns ecologists heeded that call, which or personalities. Interestingly, in bird has resulted over the past decade in a studies, the term “personality” was growing body of theoretical and em- first used as early as 1922 (Talbot pirical research that tries to elucidate 1922). When talking about animal the existence of animal personalities. personality nowadays, biologists re- Personalities are found throughout fer to consistent individual variati- a wide variety of taxa in the animal on in behavioural and physiological kingdom (Carere & Maestripieri traits that is consistent over time and/ 2013). Traits that are incorporated or over contexts (Sih et al. 2004a, in personalities are e.g. exploration, b, Réale et al. 2007, Coppens et al. aggressiveness, boldness, general ac- 2010). Behavioural ecologists were tivity, nesting behaviour, avoidance, curious about adaptive individual dif- sociability and stress-coping. ferences in behaviour and physiology Animal personality research is in the second half of the last centu- probably the fastest growing field in ry (e.g., Huntingford 1976, Clark & behavioural ecology at the moment Ehlinger 1987, Wilson et al. 1994). (Réale et al. 2010a). Evidence for The criticism of falling for anthro- consistent individual behaviour is morphism, meaning the projection found in new species at an increasing of human characteristics on animal rate, and new theoretical models ai- traits, was however prevalent in tho- med at explaining the origin and the se days. Hence only few behavioural consequences of animal personality biologists took an individual based continue to emerge. Animal perso- approach for studying behaviour or nalities have already been shown to physiology in the context of ecology have several important ecological and evolution. Variation in behaviour and evolutionary consequences (Wolf and physiology was regarded as non- & Weissing 2012) and also implica- adaptive “noise” around an adaptive tions for animal welfare (Huntingford population mean (Wilson 1998, Dall et al. 2013) and conservation (Smith et al. 2004). Before the 1960’s it was & Blumstein 2013). Considering the 12 M.W. Seltmann above, animal personality truly is a shown that personalities and behavi- very exciting and auspicious field in oural syndromes can evolve and be current behavioural and physiologi- maintained by natural (Dingemanse cal research. However, besides the et al. 2004, Wolf et al. 2007) and efforts of some authors (Réale et al. sexual (Réale et al. 2009, Schuett 2007, Réale et al. 2010a, b, Carter et al. 2010) selection. Behavioural et al. 2013) a unifying theory of ani- ecologists have worked out several mal personality has not yet emerged. important axes of animal persona- Moreover, the acclaimed recent bur- lity along which individuals can be geoning theoretical development in placed: shyness – boldness, aggressi- the field is confronted with a lack of veness – cautiousness, fast and super- empirical studies on populations in ficial explorers – slow and thorough the wild. Studying personality and explorers, proactive – reactive stress its links with stress physiology in the coping. Bold and fast explorers are wild and linking personality with tra- considered to be more successful in ditional life-history and habitat selec- constant environments with develo- tion are main issues in the field that ping routine-like behaviours and shy are addressed in this thesis. and slow explorers are supposed to be more successful in changing environ- 1.1 What exactly is animal perso- ments, showing more flexible behavi- nality? our (Cockrem 2005). It is important to note that the concept of animal The concept of animal personality en- personality does not require that traits compasses the existence of consistent are rigorously fixed. Personality traits individual differences in behaviour can vary according to an individual’s and physiology. These differences are state or its environment (e.g., Luttbeg stable over time and across contexts & Sih 2010). However, individual (Réale et al. 2007). Throughout this rank orders are often maintained (Sih thesis the broad-sense definition of 2004a, b, Bell 2007). Furthermore, personality is used. This definition animal personality research has high- does not restrict the kind of investi- lighted that variation is not only the gated behaviour, but rather looks at raw material for natural selection to correlations of one behavioural trait act on, but variation can also be the between different environmental or outcome of natural selection (Wilson temporal contexts or at correlations et al. 1994). between two different behavioural traits (Réale et al. 2010a). Corre- 1.2 Ultimate explanations for the lations between two or more beha- existence of consistent individual vioural or physiological traits are variation also called behavioural syndromes (Sih et al. 2004a, b) or coping styles With the existence of personality (Koolhaas et al. 1999), respectively. traits several important questions ari- A considerable body of studies has se: Why do we find consistent vari- Personalities in female eiders 13 ation in animal behaviour in nature? dent selection can produce and main- Is individual variability maintained tain variation in behaviour where a by natural selection and how does mixture of responsive (e.g. eaves- evolution maintain this variation, as dropping) and unresponsive indivi- one would perhaps expect natural se- duals are favoured (Dall et al. 2004, lection to eliminate variation within Wolf et al. 2008). populations? And why do we find Environmental conditions vary in consistent correlations between be- space and time. This circumstance havioural or physiological traits that has the potential to favour the co- seemingly reduce an animal’s plasti- existence of different behavioural ty- city and therefore an optimal respon- pes. Spatial variation in the environ- se to every situation? ment could mean that a population During the last decade, many the- distributes over more and less risky oretical models have been proposed habitats. Depending on which habitat explaining how evolution can main- an individual is occupying, and con- tain variation in populations, thereby sidering that behavioural plasticity allowing different behavioural types is costly, spatial variation can main- to coexist. One explanation for the tain the coexistence of more and less maintenance of behavioural variati- risk-taking individuals (Wilson 1998, on within population is differences Wolf & Weissing 2010). Temporally in individual state when behaviour fluctuating environments can also is state dependent. At any given mo- lead to the co-existence of different ment, two individuals of a population behavioural types within a popula- will differ in their state, e.g. in their tion. In great tits (Parus major), for energy reserves or regarding the en- example, selection favours different vironmental conditions they are fa- personality types in years that provi- cing. If behaviour is state-dependent ded high or low food quality (Dinge- and current state affects the costs and manse et al. 2004). Hence, heteroge- benefits of the behaviour, differences neous forms of selection can maintain in original state can lead to adaptive variation in behaviour within popula- differences in behaviour (Dall et al. tions (Dingemanse & Reale 2013). 2004). A fourth potential adaptive expla- Even though individuals would nation for personality traits is pro- not differ in their original state, ne- vided by social niche specialisation gative frequency dependent selection (Bergmüller & Taborsky 2010). This can give rise to different behavioural framework assumes that individuals types. For example, in foraging the- choose different strategies to avoid ory, individuals can adopt different social conflict, thereby increasing behavioural strategies for acquiring their fitness. food resources, with individuals being A fifth possibility for personality either “producers” or “scroungers” traits to arise is through coevolution (Giraldeau & Beauchamp 1999). Fur- with life history strategies, as previ- thermore, negative frequency depen- ously proposed by a theoretical model 14 M.W. Seltmann by Wolf and colleagues (2007). The adrenal axis (HPA axis). It develops model shows that the trade-off bet- early in an animal’s life and includes ween current and future reproduction a series of complex connections bet- can lead to different consistent indi- ween neurotransmitters, hormones, vidual risk-taking strategies within receptors and feedback mechanisms a population, as predicted by life- (e.g. von Holst 1998). The HPA axis history theory (Clark 1994). In two is associated with numerous behavi- recent reviews (Stamps 2007, Biro & oural actions. Thus, it is conceivab- Stamps 2008) it has been shown that le that a fundamental change in that consistent individual differences in complex system would be very costly personality traits could be explained and hence an overall plastic response by individual differences in how ani- is not possible (Dall 2004). The evo- mals resolve the allocation trade-off lution of a more flexible mechanism between growth and fecundity. Thus would require several steps, and in- far, only few empirical studies per- termediate forms of a new HPA axis formed on red squirrels Tamiasciurus might be rather unthrifty. The exis- hudsonicus (Boon et al. 2008) and tence of an adaptive valley in the on bighorn sheep Ovis canadensis fitness landscape might prevent the (Réale et al. 2009) have highlighted evolutionary steps necessary to deve- the association between personality lop a more flexible architecture (Wolf traits and life-history strategies. Fe- et al. 2013). Furthermore, positive male red squirrels that were more ac- feedback mechanisms, like experi- tive showed a lower own overwinter ence and skill improvement, can fa- survival, but an increased probability vour consistency in behaviour (Wolf of offspring survival. Aggressive big- et al. 2008). Related to this, winner- horn rams exhibited earlier reproduc- loser effects in competing individuals tion and a shorter lifespan than docile of a population can enhance consis- rams. tency of behaviour (Dugatkin 1997). The maintenance of consistent behaviour across time is more dif- 1.3 Proximate mechanisms of con- ficult to explain than the occurrence sistent individual variation of variation in behavioural types. The processes presented above may From a proximate point of view, the still not be strong enough to allow underlying architecture of behavi- consistent personality traits to evol- our provides adaptive explanations ve without incorporating physiology, for consistent behavioural variation. as shown by a recent theoretical mo- This will be discussed in more detail del by Wolf and McNamara (2012). in the next section. From an ultima- In their model, negative frequency te perspective, it can be costly for an dependent selection gave rise to va- individual to change the underlying riation in behaviour (see previous mechanisms that produce behavi- section). However, negative frequen- oural consistency in time. One ex- cy dependent selection alone could ample is the hypothalamic-pituitary- Personalities in female eiders 15 not generate individual consistency be weaker than genetic correlations, and correlations between traits. Only they can still be very costly to un- when physiology was included did couple (see previous section). Base- the model generate extreme and con- line concentrations of glucocorticoids sistent behavioural tendencies (Wolf (GCs), also called “stress hormones”, & McNamara 2012). Hence, to fully play an important role in daily energy understand the evolution and mainte- balance by regulating resource acqui- nance of personality traits, it is just sition (Sapolsky et al. 2000). Consi- as essential to explore the proximate dering their major importance in con- mechanisms responsible for individu- trolling energetic demands, GCs are al differences in behaviour so, as to thought to have an orchestrating key understand the ultimate reasons why role in mediating important life-his- personality traits exist (cf. Tinbergen tory trade-offs, particularly between 1963). survival and reproduction (Zera & Genes, physiology and neuroen- Harshman 2001, Ricklefs & Wikelski docrine mechanisms form the under- 2002). The link between neuroendo- lying architecture of behaviour and crine mechanisms and personality reflect correlates ofpersonality traits is especially well investigated in an (Sih et al. 2004b). Genes can exert individual’s response to stressful situ- pleiotropic effects, meaning that one ations. Thus, stress-induced concent- gene can influence the expression rations of GCs and HPA axis reacti- of two or more behavioural traits. vity are of central interest. Individual Hence, genetic correlations provide consistencies in physiological and a good explanation for consistency behavioural characteristics, that can and correlations between behavioural be correlated, have been defined as traits. Furthermore, several studies coping styles (Koolhaas et al 1999). illustrated that personality traits are Two distinct coping styles have been heritable (van Oers et al. 2004, Quinn proposed which are closely related to et al. 2009), a prerequisite for beha- personality types. Proactive stress co- vioural types to evolve. For example, ping is associated with highly aggres- through a candidate gene approach, sive behaviour, an active flight/fight studies have been able to link poly- response and a weak response of the morphisms in the dopamine receptor HPA axis when in a threatening situ- D4 gene with exploratory behaviour ation. Reactive stress coping inclu- (Fidler et al. 2007) and associate the des low aggressive behaviour, freeze gene for a serotonin transporter with response and a weak response of the aggressive and risk-taking behaviour HPA axis when in a threatening situ- (Champoux et al. 2002). ation (Koolhaas et al. 1999). It has Like genes, hormones can also been suggested that individuals with cause pleiotropic effects on different proactive coping styles show lower behaviours, thereby explaining why behavioural flexibility and fast reac- behaviours can correlate. Although tions to environmental change, but pleiotropic effects of hormones might the response can be inaccurate (Cop- 16 M.W. Seltmann pens et al. 2010). Individuals that a weaker stress response than slow- exert a proactive coping style rely on shy explorers (Baugh et al. 2012) and internal organizations of behaviour slow explorers showed a faster incre- (Coppens et al. 2010). Reactive co- ase in CORT and higher peak levels ping styles are associated with higher of CORT (Baugh et al. 2013). Inte- behavioural flexibility and slow reac- restingly, zebra finches (Taenopygia tions to environmental change. How- guttata) that were artificially selected ever, those changes are directed by for weak and strong stress responses environmental stimuli, showing that also showed correlated behavioural individuals with a reactive coping patterns in exploration and risk-ta- style can adapt better to environmen- king (Martins et al. 2007). However, tal change (Coppens et al. 2010) The zebra finches with higher CORT le- ability to cope with sudden or new vels took more risks and were more environmental disturbances has con- explorative, an observation that is siderable effects on life-history trade- contradictory to the coping style li- off decisions, e.g. the reallocation of terature (Koolhaas et al. 1999). Alt- energy between immediate survival hough contradictory, these results are and long-term reproductive success nevertheless providing evidence that (reviewed in Angelier & Wingfield HPA axis reactivity and personality 2013). Similar patterns in coping sty- traits are closely linked. les have been found in two selected Furthermore, differences in the lines of great tits (fast and slow explo- structure of the hippocampus of an ration; Groothuis & Carere 2005) and individual can be related to its coping in genetically selected lines of labo- style (Sluyter et al. 1994). ratory mice (Mus domesticus) (short Some studies also suggest that and long attack latencies; Benus et al. differences in metabolic rate can pro- 1991) . When exposed to stress, fast mote differences in behaviour (Biro exploring great tits as well as mice & Stamps 2010) and that incorpora- with short attack latency showed a ting metabolic variability can help in weaker HPA axis response (Veene- understanding why individuals beha- ma et al. 2004, Carere et al. 2003). ve consistently over time and across A recent study on great tits from the contexts (Careau et al. 2008). A pro- same selection lines (Groothuis & mising approach for future persona- Carere 2005) has provided evidence lity research is the recently proposed for a genetic correlation between pace-of-life syndrome (POLS; Réale personality traits and stress physio- et al. 2010b). The POLS integrates logy (Baugh et al. 2012). Individuals life-history, behaviour and physiolo- that were phenotypically selected for gy into a holistic framework, aiming being fast-bold explorers exhibited to explain animal personalities. Personalities in female eiders 17

2. Aim of the thesis I estimated the repeatability of FID, physiological traits (CORT and body The overall aim of this thesis is to temperature) and nest-site characte- depict how the life-history trade-off ristics (nest cover and nest distance between survival and fecundity is to closest shoreline). linked to consistent individual diffe- Chapter I focuses on elucidating rences in incubating female eiders. the relationship between baseline Throughout the four chapters of this corticosterone levels and fitness in thesis, I investigate how this essential the light of the CORT-fitness hypo- life-history trade-off could be resol- thesis. This hypothesis states that an ved through individual differences elevated baseline concentration of in escape behaviour, stress physio- CORT signals an impaired ability of logy, individual quality and nest-site an individual to cope with the pre- selection (Fig. 1). Of special interest vailing environment, which can lead is flight initiation distance (hereafter, to low fitness. The study examines FID) measured in a risky situation links between individual quality and (a measure of boldness, sensu Réale baseline CORT levels in blood se- et al. 2007). Moreover, I focused on rum and faeces, explores whether the physiological correlates of animal relationship between baseline body personalities, namely serum and fa- temperature and individual quality ecal baseline CORT concentrations, is modulated by nest-site habitat and serum stress-induced CORT con- determines the link between CORT centrations and baseline and stress- and nest success, a correlate of fit- induced body temperature. In a life- ness. history context, boldness and stress Chapter II explores how stress responsiveness reflect the trade-off responsiveness is connected to bold- between investing in survival versus ness and individual quality. It also reproduction. investigates how maternal stress co- Repeatability is defined as the pro- ping is linked to incubation duration, portion of the total variance accoun- a fitness component. ted for by differences among groups Chapter III continues in exami- (Sokal & Rohlf 1995). It is essential ning the adaptive potential of stress for testing the reliability of multiple responsiveness by asking how pre- measurements through time or over dation risk modifies the relationship contexts (Carter et al. 2013). Further- between stress responses and parental more, for behavioural and physiologi- investment, and that between stress cal traits to be qualified as personality responsiveness and fitness (nest suc- traits they have to be repeatable (Sih cess). et al. 2004a, Reale et al. 2007). Re- Chapter IV investigates the asso- peatability of CORT is, furthermore, ciation between stress coping styles one of the underlying assumptions of and nest-site selection. Furthermo- the CORT-fitness hypothesis (Bonier re, I elucidate whether variation in et al. 2009a). In chapters I, II and IV boldness, stress responsiveness or 18 M.W. Seltmann nest-site characteristics can explain component. variation in nest success, a fitness

Personalities in female eiders

The CORT-fitness hypothesis Chapter I: Exploring the relationship between baseline corticosterone, individual quality and fitness and nest-site habitat

Chapter II: Exploring the relationship between stress responsiveness and boldness and individual quality

Chapter III: Exploring the relationship between stress responsiveness and maternal investment and predation risk

Chapter IV: Exploring the relationship between personality and nest-site habitat Figure 1. A conceptual outline of the thesis, visualizing the main functions of the four chapters.

Figure 2. Female eider, incubating in a nest with a decent roof (© Heikki Eriksson). Personalities in female eiders 19

3. Materials and methods covered by closed stands of pine (Pinus sylvestris) and spruce (Picea 3.1 Study species abies) with an understory of juniper and other shrubs. Island area ranged All data for this thesis were collec- from 0.05 ha to 10.49 ha (Lindström ted on female eider ducks (Somate- 2003). White-tailed sea eagle (Ha- ria mollissima) (Fig.2). The eider is liaeetus albicilla), eagle owl (Bubo a long-lived ground-nesting seabird bubo), American mink (Neovison that breeds in the northern parts of vison) and raccoon dog (Nyctereutes Europe, North America and eastern procyonoides) are the main predators Siberia. Females are the sole incuba- of incubating females, and hooded tors and show high nest attentiveness crows (Corvus corone cornix) and (Bolduc & Guillemette 2003). They gulls (Larus spp.) the main egg pre- are capital precocial breeders, which dators. All study islands are protected rely almost entirely on bodily reser- by a prohibition on landing. ves during incubation, losing up to 40% of their pre-laying body weight 3.3 Field methods (e.g., Parker & Holm, 1990). Fema- les incubate their clutch for about 26 We captured incubating females on days, after which the hatched duck- their nests using hand nets. Trapping lings leave the nest within 24 hours. took place predominantly during the Both eggs (Öst et al. 2008a) and incu- end of the incubation period in May bating females (Jaatinen et al. 2011, or early June to minimize nest deser- Ekroos et al. 2012) are subject to sig- tion. Trapped females were ringed nificant predation pressure. Eiders in with a standard metal ring, weighed this study population arrive at their on a spring scale and the length of the breeding grounds in March and April radius-ulna was recorded. An exten- and start incubating in the end of Ap- sive overview on collected variables ril – end of May. and techniques are to be found in Ta- bles 1 and 2. 3.2 Study area 3.4 Laboratory methods All studies in this thesis were conducted on a well-studied eider po- The identification of CORT concen- pulation in the archipelago surroun- trations of faecal and serum sam- ding Tvärminne Zoological Station ples via radioimmunoassay (RIA) (59°50´N, 23°15´E), on the Baltic was carried out at the University of Sea in southwestern Finland (Fig. 3). Fairbanks, School of Fisheries and Female eiders breed in two contras- Ocean Sciences, Juneau, AK, USA . ting habitats: on small open granite A validation of the serum corticoste- islands, which are sparsely covered rone RIA kit (ImmuChemTM Double with patches of grasses, herbs or oc- Antibody, Corticosterone, 125I RIA casionally junipers (Juniperus com- Kit, MP Biomedicals, Orangeburg, munis) or on larger forested islands, NY) for eiders is provided by Nils- 20 M.W. Seltmann son (2004). A double antibody RIA that is freely available on the internet kit (ImmuChemTM Double Antibo- (R Core Team 2013). In this thesis dy, Corticosterone, 125I RIA Kit, MP generalized and linear mixed models Biomedicals, Orangeburg, NY) for were used to analyse the data. Repea- corticosterone was validated for use tabilities and corresponding standard with extracted faeces of European ei- errors, confidence intervals and p-va- ders (I). lues (I, II, IV) were obtained by using the functions rpt.remlLMM, rpt.bi- 3.5 Data analyses nomGLMM.multi and rpt.remlLMM. adj from the R software package rptR All statistical analyses and graphs for (Nakagawa & Schielzeth 2010). the chapters of this thesis were per- formed with the statistical software R

Figure 3. Map showing the archipelago around Tvärminne Zoological Station (star symbol on right map) at the entrance of the Gulf of Finland. Islands where females were trapped are marked in black, other islands are in grey. Personalities in female eiders 21

Table 1. Summary of all variables collected and analysed in this thesis, with variable name, its function, its definition and the corresponding chapters of the thesis. Variable Function Definition / method Chapter Behaviour / female state Flight initiation distance Boldness Distance between approaching II, IV researcher and female flushing off the nest Incubation onset Competition for Estimated via egg flotation IV nest sites Hatch date Incubation timing Estimated via egg flotation I, II Maternal experience Age / experience No. of years since bird was first I, II, IV ringed Body condition Energy reserves Log (weight at hatching) ~ log I, II, IV (radius-ulna) Clutch mass Maternal invest- Total clutch mass corrected for I, III ment incubation stage Physiology Baseline corticosterone Health proxy Blood sample within 3 min after I in serum trapping Baseline corticosterone Health proxy Faeces sample from nest and/or I in faeces female Baseline body tempe- Homeostasis Rectal temperature I rature Stress-induced corticos- Stress responsi- Blood sample after handling II, III, terone in serum veness IV Stress-induced body Stress responsi- Rectal temperature IV temperature veness Environment Nest cover Degree of conce- Skywards photograph made with III, IV alment fisheye lens Nest distance to nearest Distance to safe- GPS and ArcGIS IV shoreline ty in water Island-specific predation Degree of risk No. of killed females per census- III risk ed nest per island Fitness Incubation duration Proxy for duck- Time difference between real II ling condition hatch date and estimated date of incubation onset Probability of clutch Reproductive Successful if at least 1 duckling I hatching success hatched Viable proportion of the Reproductive Proportion of live ducklings to III, IV clutch success dead / unhatched ducklings 22 M.W. Seltmann

Table 2. Summary of the control covariates included in different analyses, with the control covariate, its function, a definition and the corresponding chapters of the thesis. Variable Function Chapter Control covariates Potential effects on Time of day Daily rhythms in body temperature and corti- II, IV costerone Year Breeding phenology II Time to first blood sample Baseline serum corticosterone / body tempe- I, III, IV rature Time to second blood sample Stress-induced serum corticosterone / body II, III, IV temperature Time after first trapping Baseline serum corticosterone / body tempe- I rature Island identity Nest distance to nearest shoreline IV Incubation stage Clutch mass I, II, III, IV Clutch size Incubation duration II Personalities in female eiders 23

4. Main results and discus- In particular, the repeatability of FIDs sion (II) ranged from low (between three consecutive seasons) over moderate (between two consecutive seasons) to 4.1 Female stress coping profiles high (within each season). Variation and nest characteristics are repea- in the repeatability of FID could be table due to females changing their beha- Significant repeatability suggests that viour over time or due to different a trait is to some extent genetically sample sizes within and between determined. Furthermore, repeatabili- seasons. Within seasons, females do ty estimates set an upper limit for he- not change their behaviour strongly ritability. In a recent review, Bell and and multiple measurements of seve- colleagues (2009) demonstrated that ral females are available, resulting behaviour in general is often repea- in higher and more reliable repeata- table. From the studies analysed for bility estimates. The lower repeata- their review, they estimated an ave- bility estimate over several seasons rage value for repeatability of 0.37. could be caused by the inevitable This value actually fits well with the fact that we cannot trap every female 3-year estimate of FID, being 0.37 every year, leading to a much lower (II), too. To date, no review on the re- sample size for repeatability estima- peatability of physiological traits has tes over seasons. More importantly, been published, although there is ac- however, annual variation in mater- cumulating evidence for those traits nal investment could be responsible being heritable and repeatable (e.g. for the lower repeatability estimate Evans et al. 2006, Romero & Reed over seasons, as clutch mass or clutch 2008). Female escape behaviour size can either positively (Osiejuk & (FID), measures of baseline serum Kuczyński 2007) or negatively (Alb- and faecal CORT (CORT0 and FC), recht & Klvaňa 2004) affect FID in baseline body temperature, measures birds. of stress-induced CORT and body Thus, these estimates might be temperature were significantly re- less reliable or accurate than within- peatable over time (Tab. 3). Hence, season estimates. Repeatability of these traits represent coherent and most of our measured physiological individually consistent coping styles. traits is quite similar, and sample si- Furthermore, nest-site characteristics zes are appropriate. Only FC exhi- were significantly repeatable as well, bited lower repeatability than other but with estimates showing a low re- physiological measures. A reason for peatability. this could be because CORT is exten- Estimates of repeatability ranged sively metabolized before excretion between slightly (0.13) and highly and reflects a longer-term measure (0.80) repeatable (see Martin & Bate- of stress than baseline serum CORT. son (1986) for an interpretation of the Despite high sample sizes and mul- strength of repeatability estimates). tiple repeated measures, it can prove 24 M.W. Seltmann

Table 3. Repeatability estimates for flight initiation distance FID (m), nest distance to shore (adjusted for island identity; m), proportional nest cover (%), stress-induced CORT concentration (ng/ml), stress-induced body temperature (°C), baseline serum CORT and faecal CORT concentration (ng/ml) and baseline body temperature (°C). Shown are the years of observation, the repeatabilities and their associated standard errors, 95% confidence intervals, P-values, and the number of observations and individuals (in parentheses) and the corresponding chapter of the thesis in which it was estimated. Trait Years R SE CI P N Chapter FID 2009 0.80 0.04 0.73, 0.84 < 0.001 154 (65) II FID 2010 0.76 0.04 0.70, 0.81 < 0.001 166 (60) II FID 2011 0.76 0.04 0.67, 0.79 < 0.001 168 (66) II FID 2009–2010 0.69 0.06 0.57, 0.74 < 0.001 101 (26) II FID 2010–2011 0.54 0.12 0.32, 0.67 < 0.001 97 (22) II FID 2009–2011 0.37 0.14 0.15, 0.57 < 0.05 40 (7) II Nest distance to 2008–2012 0.20 0.04 0.11, 0.27 < 0.001 531 (213) IV shore (adj) Proportional nest 2008–2012 0.22 0.05 0.10, 0.24 < 0.05 620 (238) IV cover Stress-induced 2009–2011 0.27 0.09 0.12, 0.42 < 0.05 240 (110) IV CORT Stress-induced 2010–2012 0.25 0.07 0.09, 0.37 < 0.01 320 (147) IV body temperature Baseline serum 2009–2011 0.27 0.08 0.11, 0.43 < 0.01 237 (108) I corticosterone Faecal corticos- 2008–2011 0.13 0.05 0.04, 0.26 < 0.05 415 (168) I terone Baseline body 2009–2011 0.25 0.06 0.16, 0.37 < 0.001 371 (167) I temperature difficult to find reliable repeatability tes of nest-site characteristics were estimates despite high sample sizes still relatively low. A possible expla- and multiple repeated measures. nation is that we did not control for It is rather unsurprising that nest- nest success in the analysis. Breeding site characteristics are significantly dispersal increases after nest failure repeatable, considering the high bree- (Öst et al. 2011), which can potenti- ding philopatry in the investigated ally reduce the repeatability of nest- population (IV). The median bree- site characteristics between seasons. ding dispersal distance is 21 meters Inter-individual variation in FID between seasons (Öst et al. 2011). (II) or behaviour in general has se- Sometimes females use exactly the veral ecological and evolutionary same nest-cup for many years in a consequences (reviewed in Wolf row. However, repeatability estima- & Weissing 2012), e.g. differential Personalities in female eiders 25 selection on personality types (cf. when investigating links between Biro & Post 2008). A strong indivi- CORT concentrations, individual dual component explaining variation quality, environmental effects and in predator avoidance behaviour, as fitness. Rensel and Schoech (2011) exemplified by FID, is seemingly a found repeatability of baseline CORT general phenomenon (birds: Carrete concentrations in Florida scrub-jays &Tella 2010; mammals: Malmkvist Aphelocoma coerulescens, which & Hansen 2002; fish: Coleman & was mostly driven by correlations Wilson 1998; reptiles: Carter et al. between baseline CORT concentra- 2010). However, the relatively high tions in nestlings and yearlings. They consistency of individual FIDs does suggest that the early environment is not mean that escape behaviours are shaping the HPA axis of developing strictly fixed. FIDs in female eiders nestlings. This could certainly be the still show plasticity and can be af- case, as the early environment can fected by a variety of factors such as influence postnatal individual levels maternal experience, predation risk of CORT, as shown for some mam- (II) and probably also the nesting en- mals (Hudson et al. 2011). Another vironment (IV). explanation of repeatability of base- The low but significant repeatabi- line CORT concentrations is maternal lity of baseline CORT concentrations programming of the HPA axis at an in serum and faecal samples (I) is a early stage of development. In birds, prerequisite for the CORT-fitness hy- maternal hormones are deposited in pothesis (Bonier et al. 2009a). The re- the egg yolk, affecting the HPA axis lative small intra-individual variation reactivity of nestlings (e.g., Love compared to inter-individual variati- & Williams 2008). Since eiders are on of CORT0 and FC patterns allows precocial breeders, with ducklings inference about the fitness conse- staying in the nest for only one day, quences of individual stress hormo- the nest-site environment as such has ne profiles. Furthermore, the results probably little influence in shaping (I) are in line with other studies that duckling HPA axis reactivity. Mater- show repeatability of CORT0 in other nal programming may, therefore, be a birds (great tits: Cockrem & Silverin promising mechanism that should be 2002; black-browed albatrosses Tha- explored in future studies examining lassarche melanophrys: Angelier et the repeatability of baseline CORT al. 2010). Some previous studies have concentrations in female eiders. also shown that FC concentrations The repeatability of baseline are repeatable (greylag geese Anser body temperature (I), together with anser: Kralj-Fišer et al. 2007; upland its strongly positive correlation with geese Chloephaga picta leucoptera: baseline faecal CORT, demonstrates Gladbach et al. 2011). These findings its use as a complementary indicator suggest that baseline CORT concent- of stress. An elevated baseline body rations have a strong individual com- temperature seems to represent a ponent, which should be considered long-lasting stress response, since fa- 26 M.W. Seltmann ecal CORT concentrations represent stress-induced CORT responsiveness a longer-term cumulative measure of is, in fact, a more stable individual stress (Möstl et al. 2005). In support trait than baseline CORT concentra- of this concept are findings showing tions. This does not seem to be the that changes in body temperature may case in female eiders, however, since be detectable for days after a single the repeatability of both measure- stressful event (Meerlo et al. 1996), ments was intriguingly similar (R = just as for CORT concentrations (von 0.27; I, IV). Holst 1998). Females nesting on open Similar to stress-induced CORT islands showed higher baseline body concentrations, stress-induced body temperature when in worse condition. temperature (I) showed low but sig- Thus, high baseline body temperatu- nificant repeatability in female eiders. res could generally indicate that indi- The repeatability of stress-induced viduals are facing a more challenging body temperature has only been as- environment, as nesting on open is- sessed once before in wild animals lands s frequently accompanied by a (Careau et al. 2012). In Eastern more extreme thermal regime, higher chipmunks (Tamias striatus) stress- predation risk by aerial predators or induced rise of body temperature both. can be influenced by correlates of In wild and laboratory birds, re- heat production and dissipation such ported repeatability estimates for as body mass or energy expenditure stress-induced CORT concentrations (Careau et al. 2012). Considering the at 30 minutes of handling range from manifold extrinsic and intrinsic fac- low to moderate (Kralj-Fišer et al. tors affecting body temperature, it is 2007, Cockrem et al. 2009). Ourmea- highly interesting that we still find si- sure (R = 0.27, Tab. 3) of stress-in- gnificant inter-individual variation in duced CORT repeatability fell within stress-induced body temperature just this range (II). A consistent stress reas in measures of baseline body tem- sponse in CORT towards disturbance perature. It has been suggested that seems to reflect individual sensitivity stress-induced rise in body tempera- of the HPA axis, with animals having ture represents a controlled fever (Ca- distinct coping styles (Koolhaas et al. banac 2006) that might be involved 1999). CORT stress responsiveness in the “fight or flight” response and appears to be generally repeatable in has adaptive value (Oka et al. 2001). birds. Considering that consistency Taken together, the repeatabilities in bird FIDs is seemingly a general of baseline and stress-induced body phenomenon too, both behavioural temperature strongly suggest that the- and physiological responses to stress se variables provide two alternative could form a conjunct suit of traits stress indicators that complement the determining an individual’s perfor- use of CORT measures when investi- mance in risky situations (II). Cock- gating stress coping styles in animals. rem and Silverin (2002) suggest that Personalities in female eiders 27

4.2 Baseline CORT as a context- The interactive effect of timing dependent predictor of individual of breeding and reproductive invest- quality and fitness ment on CORT0 and that of timing Several studies have investigated the of breeding and body condition on relationship between CORT0 or FC, FC suggest a common denominator individual quality and fitness. Interes- linking these findings. The general tingly, the results are not consistent, increase in serum CORT levels with as negative, positive and non-signi- increasing reproductive investment ficant relationships between baseline (i.e. total clutch mass) was most pro- CORT and fitness have been found nounced in the late breeding season. (reviewed in Bonier et al. 2009a). Correspondingly, only late breeders Chapter I shows that, in female ei- showed an increase in FC with in- ders, the relationship between base- creasing body condition. There are line CORT and individual quality is at least three possibilities for explai- context dependent (see also Angelier ning these common patterns. First, et al. 2010). Female body condition, elevated CORT levels might reflect an important correlate of individual an intensified foraging effort, since quality, is generally negatively asso- producing larger clutches later in the ciated with CORT0 and FC. How- season becomes more challenging ever, this relationship is modulated for females. The CORT-adaptation by breeding experience and breeding hypothesis, which states that higher phenology. This context-dependency CORT levels facilitate foraging acti- accentuates the need for cautious in- vity and parental care, supports this terpretations of the relationship bet- assumption (e.g., Crossin et al. 2012). ween CORT patterns and phenotypic The second explanation is based on quality (Fig. 4). The results support the ‘preparative hypothesis’ (Rome- the CORT-fitness hypothesis, since ro 2002). Breeding late in the season CORT0 tends to decrease with in- might force the female to accelera- creasing body condition. However, te embryonic development of their younger breeders show almost no clutch. This adaptive mechanism connection between CORT and body could be realized by mobilizing ener- condition, whereas older breeders ex- gy reserves which is mediated via hibit the steepest increase in serum higher CORT levels and only females CORT concentrations. This finding in good body condition may be able may indicate an age effect on stress to do so. Last, late-breeding females tolerance, as aging often goes along in good condition exhibiting increa- with an increase in baseline CORT sed CORT levels might just depict concentrations (Stein-Behrens & Sa- the efforts involved in gathering the polsky 1992, Purnell et al. 2004). It is required resources and this pattern conceivable that such effects of sene- might not bear an adaptive mecha- scence on stress tolerance are exacer- nism. For example, whereas female bated in birds in poor condition. eiders laying large clutches generally show higher survival than those lay- 28 M.W. Seltmann

Figure 4. CORT0 levels decreased with increasing body condition (A). CORT0 of older females (solid line O, black filled dots) decreased more rapidly than those of intermediate-aged (dashed line M, gray filled dots) and young individuals (dotted line Y, open dots). CORT0 was also affected by reproductive investment (B). A negative association between reproductive investment and CORT0 was evident early in the breeding season (dotted line E, open dots), a positive association late in the season (solid line L, filled black dots), and essentially no association during the mid-season (dashed line M, filled grey dots). ing smaller ones (Yoccoz et al. 2002), the environment. In fact, the negative Descamps and colleagues (2009) association between average ambient showed that this pattern was actually temperature and female body weight reversed when there was heightened at hatching might suggests that nes- exposure to avian cholera. This result ting females in this population may suggests that female eiders may only be vulnerable to heat stress (Öst et al. pay the fitness costs of high reproduc- 2008a). In addition, current research tive effort under unfavourable condi- emphasizes the possibility that per- tions. ceived risk of predation and predati- Chapter I shows that the regulation pressure could explain the interre- on of body temperature during incu- lationships between nesting habitat, bation was affected by an interaction individual quality and baseline body between individual quality and en- temperature (reviewed in Clinchy et vironmental harshness. An elevated al. 2013). The white-tailed sea eagle body temperature was exhibited only (Haliaeetus albicilla) poses a consi- by females in poor body condition derable threat to female survival, es- on open islands. On those islands, pecially on open islands. the environmental conditions are Finally, females with increased more challenging, since incubating CORT levels in both their blood females are more exposed to harsh stream and their faeces suffered from weather and direct sunlight than on lower hatching success (I), a result forested islands where denser vege- consistent with the CORT-fitness hy- tation offers better protection from pothesis. Elevated CORT concentra- Personalities in female eiders 29 tions of females may per se provide 4.3 Link between stress responsive- an explanation for this observati- ness and boldness is dependent on on. Maternal corticosterone can be individual quality passed from the mother to the eggs In chapter II, I investigate the link (e.g., Hayward & Wingfield 2004, between boldness (FID) and stress- Rubolini et al. 2005), and elevated induced CORT, since glucocorticoids CORT levels in ovo may both redu- are likely to be involved in educing ce hatching success and lead to wor- consistent individual patterns in be- se conditioned offspring at hatching haviour. Studies have shown that (e.g., Saino et al. 2005). Interestingly, CORT is an important factor in medi- CORT0 as well as FC levels proved ating escape behaviours (Wingfield et to be better predictors for nest suc- al. 1998, Thaker et al. 2010, Atwell et cess in eiders than body condition, al. 2012). Different mechanisms have which is an important determinant of been proposed in how CORT is invol- nest success in this species (Lehikoi- ved in shaping behavioural stress res- nen et al. 2010). ponses (Carere et al. 2010): (a) Stress The fact that CORT concentrations physiology determines behaviour, (b) are negatively correlated with a suite additional factors jointly determine of individual quality metrics and with stress physiology and behaviour, and a direct measure of fitness provides (c) behaviour determines physiology. evidence that the CORT-fitness hy- While chapter II is unable to resolve pothesis holds for eiders and perhaps this issue, it sheds light on the cova- also for other capital breeders with a riation of stress responsiveness and precocial mode of development. By risk-taking behaviour in female eiders highlighting the context dependen- by placing it in a life-history context. cy of the interrelationship between This covariation is well-documented CORT secretion, individual quality and forms the basis of consistent co- and fitness, these results contribute ping styles in animals (Koolhaas et to elucidating the seemingly contra- al. 1999, Coppens et al. 2010). How- dictory views on theserelationships ever, it has not been acknowledged (Bonier et al. 2009a, b, Dingemanse that this link might be modulated or et al. 2010). The findings of chapterI even controlled by individual state or particularly emphasize that differen- status (Quinn & Cresswell 2005). ces between high- and low-quality in- I found that in general, females dividuals in their ability to cope with with an elevated stress response had environmental stressors may only longer FIDs, i.e. they were less bold. become apparent in the most challen- This pattern appears to be a robust ging of environments. consequence of inherent differences in boldness rather than, e.g., differences in the time needed to detect and react to a predator, which also depends on nest concealment (IV). In- 30 M.W. Seltmann terestingly, the link between boldness life-histories. Kralj-Fišer and colle- and stress responsiveness in female agues (2010) argue that modulatory eiders runs opposite to the conventio- factors of the dominance hierarchy nal definition of proactive and reacti- could be responsible for this pattern. ve stress coping styles. According to This might hold for female eiders, the prevailing view, proactive or bold too, since females occupy consistent individuals that are characterized by rank orders in brood rearing crèches. weak stress responsiveness show also However, the simplest explanation an active fight/flight response. Re- for the apparently aberrant stress co- active, shy individuals show strong ping styles of female eiders may re- stress responsiveness and respond to flect their great reliance on crypsis environmental risks with a freeze/ during incubation, which may pre- hide reaction (e.g. Koolhaas et al. vent the activation of the flight res- 1999; Schjolden et al. 2005). ponse in bold individuals. In contrast, Considering that individuals with most of the existing studies on proac- slow reactions to disturbance are ex- tive and reactive stress coping styles pected to show a reactive stress co- have been done either in mammals or ping style associated with high stress in bird species not primarily relying responsiveness (cf. Quinn & Cress- on crypsis to avoid predation (Japa- well 2005), we actually found that nese quail Coturnix coturnix japoni- bold females with short FIDs had a ca, chicken Gallus domesticus and lower stress-induced stress respon- great tits) (reviewed in Koolhaas et se. Contradictory stress coping sty- al. 1999, Cockrem 2007). les have also been found in greylag Chapter II illustrates that despite geese, where more aggressive indivi- the relative consistency of individual duals showed a positive correlation flight responses, FIDs can be flexib- with stress-induced concentrations of le and modulated by stress-induced faecal corticosterone (Kralj-Fišer et CORT concentrations, female bree- al. 2010). It is noteworthy that in our ding experience and body condition population of eiders a strong positive (Fig. 5). Young incubating females trend exists between female shyness, showed the expected increase in FIDs which is correlated with a higher con- with increasing magnitude of the centration of stress-induced CORT stress response, however, the direc- and female aggression (Marin Selt- tion of the relationship was reversed in mann, unpubl. data). This is in line the oldest breeders. We propose four with the results from greylag geese not mutually exclusive explanations (Kralj-Fišer et al. 2010). One could for the interactive effects of stress speculate that coping styles in Anse- responsiveness and female breeding riformes might show a different pat- experience on boldness. First, this tern than in mammal and bird (Pas- pattern may reflect a direct effect of seriformes and Galliformes) model senescence. Studies have indicated species (Koolhaas et al. 1999, Care- that the oldest individuals may be re et al. 2003), because of different unable to dampen their physiological Personalities in female eiders 31

Figure 5. Stress-induced CORT concentrations and FIDs of female eiders in relation to (a) (minimum) years of breeding experience and (b) body condition. In panel (a), the solid line denotes females with little breeding experience, the dotted line females having intermediate breeding experience and the dashed line females with long previous breeding experience. In panel (b), the solid line denotes females in poor body condition, the dotted line females in intermediate body condition and the dashed line females in good body condition. response to acute stressors (Goutte et tin. Its concentrations typically incre- al. 2010; Wilcoxen et al. 2011). How- ase with advancing age in seabirds ever, we found no relationship bet- (e.g., Angelier et al. 2007a, b), and ween female breeding experience and such interactive hormonal regulation stress-induced CORT concentrations may tend to inhibit flight reactions (II) and this relative age-insensitivity of incubating older females. Finally, of the CORT stress response agrees female breeding experience may be with studies conducted on other se- correlated with the ability to assess abirds (e.g., Angelier et al. 2007a). local predation risk (Öst & Steele Second, although stress may trigger 2010), which may directly influence the release of similar amounts of boldness. Stress physiology and CORTs into the blood irrespective of boldness might become decoupled female age, CORT receptors may be in older females through habituation progressively down-regulated with of those individuals to their relatively advancing age (e.g., Stein-Behrens & ‘safe’ nest surroundings. This effect Sapolsky 1992), and the concomitant might even be enhanced by the fema- attenuation of the stress response may les’ social environment. Older birds facilitate an increase in reproductive are found in more centrally located performance with age (Heidinger nests on islands, where nest densities et al. 2006). Third, CORT-mediated are higher (Öst & Steele 2010). Tho- stress responses may be balanced se females might be bolder, because or even overridden by the action of boldness tends to increase in social other hormones, particularly prolac- situations (e.g., van Oers et al. 2005). 32 M.W. Seltmann

In addition, the relationship between the highest (Ekroos et al. 2012). Shy CORT and FID was more pronounced individuals may put a higher empha- in females with lower body condition sis on their own survival during incu- than in females in good body condi- bation, and reducing incubation con- tion. Following life-history theory, stancy is one way to achieve that aim we might hypothesize that the expec- (cf. Martin & Schwabl 2008). ted fitness value of the current bree- To conclude, the results of chapter ding attempt may be low for females II help to explain why stress respon- in poor condition and thus they might siveness may correlate with survival rather prioritize their own than off- (e.g., Angelier et al. 2009), as the ten- spring survival (e.g., Stearns 1992). dency to take risks by less stress res- This view is supported by studies that ponsive individuals may place them show that hatching success is lower at greater risk of predation. I also for female eiders in poor condition demonstrate that the effects of indivi- (Lehikoinen et al. 2010) and that the dual quality and stress physiology on current brood is more often aban- personality traits should not be stu- doned by those females shortly after died in isolation, because their effects hatching (Bustnes & Erikstad 1991, are likely to be intertwined. Kilpi et al. 2001). As individual body condition shows high annual repeata- 4.4 Links between stress responsi- bility (Jaatinen & Öst 2011), it seems veness, maternal investment and likely that individual boldness in ei- fitness are shaped by predation risk ders is influenced by body condition Chapter II demonstrated the link bet- (cf. Luttbeg & Sih 2010). ween stress responsiveness and risk- Both body condition as well as taking behaviour. In chapter III, I ela- FID affected incubation duration, a borate on these findings, by exploring fitness proxy in eiders. Females in how the value of current reproduction poor body condition had a shorter in- and predation risk, both of which cubation period, which accords with are closely linked to risk taking, in- the notion that such females can redu- teractively modify the acute stress ce mass loss by keeping their incuba- reactivity. Under low predation risk, tion time short (Hanssen et al. 2002). females exhibited a weaker stress re- On the contrary, females in good con- sponse when they had invested more dition may be capable of bearing the in current reproduction, whereas un- costs of mass loss that result from a der high predation risk, this pattern longer incubation time, thereby fa- was reversed. The stress response cilitating offspring quality (Hanssen was weaker for females nesting in et al. 2002). Furthermore, females more covered nests and it was also with longer FIDs had an abbreviated negatively associated with the viable incubation period. This agrees with proportion if the clutch. Once more, our hypothesis that shy individuals the relationship was context-depen- should incubate faster when predati- dent: reproductive success decreased on pressure on incubating females is Personalities in female eiders 33 with increasing CORT reactivity un- as well as larger clutches (Yoccoz der low predation risk, but increased et al. 2002) are generally associated under high predation risk. This con- with higher survival. Considerable text dependency of CORT reactivity costs for producing larger clutches is similar to the findings on baseline may arise merely under challenging CORT of chapter I. conditions, such as during disease When future fitness expectations outbreaks (Descamps et al. 2009) or are high, individuals should be less under elevated predation risk (III). willing to take risks (Clark 1994, Wolf When breeding conditions deteriora- et al. 2007, Nicolaus et al. 2012). Ne- te, increased adrenocortical sensitivi- vertheless, the results are contradicto- ty can depict such costs (Criscuolo et ry. Larger clutch size has been associ- al. 2006). ated with greater risk taking (Forbes Females in covered nests showed et al. 1994, Albrecht & Klvaňa 2004) attenuated stress reactivity. We sug- and attenuated stress responses (Len- gest three different explanations as to dvai et al. 2007). In contrast, larger why this pattern exists. First, females clutches have also been linked with nesting in covered nests may show risk averseness (Osiejuk & Kuszyński decreased stress reactivity, because 2007) and stronger stress responses they are more confident in escaping (Criscuolo et al. 2006). In eiders, it detection. In ground-nesting birds, has been argued that the increased nest cover has been related to post- costs of incubating enlarged clutches poned flight behaviour (Albrecht & lead to potentiated stress reactivity Klvaňa 2004) and increased trappabi- (Criscuolo et al. 2006). We suggest lity (Öst & Steele 2010). Second, in that these apparent contradictions can open nests, frequent exposure to ae- be resolved by considering the inten- rial predators might come along with sity of predation risk and the species- increased stress reactivity. Finally, specific emphasis on current versus females nesting in covered nests may future fitness. Reduced stress respon- be generally less responsive to envi- siveness is related to shorter FIDs ronmental stressors (IV). (II), and this association may ensure An immediate increase in CORT breeding constancy (Lendvai et al. levels should facilitate survival at 2007) under low predation risk and/ the expense of current reproduction or low future fitness expectations. (Breuner et al. 2008). Surprisingly, However, under high risk of preda- female eiders showed a positive re- tion preparing for potential attacks lationship between increasing CORT elevated stress responsiveness may levels and reproductive success. The be adaptive, particularly in long-lived CORT adaptation hypothesis pro- species (Romero 2002, Bókony et al. vides a possible explanation, as it 2009). In female eiders, body condi- links reproductive effort with ele- tion at hatching is positively linked to vated baseline CORT levels and clutch size (Öst et al. 2008b). Better reproductive success (Bonier et al. body condition (Ekroos et al. 2012) 2009a). Under high predation risk, 34 M.W. Seltmann an increase in CORT secretion could exist if proactive and reactive coping promote clutch survival. Higher ma- styles show differential adaptive va- ternal CORT levels speed up the rate lues depending on the environmental of embryonic development (Schmidt context (Cockrem 2005, Blas et al. et al. 2009). This mechanism might 2007, Breuner et al. 2008). Particu- help to keep the incubation period larly, proactive individuals might short, as long incubation periods can perform better in constant environ- increase the risk of female and clutch ments, whereas reactive individuals predation (Martin & Schwabl 2008). are more successful in variable envi- Similarly, shy eider females with lon- ronments (Cockrem 2005). In eiders, ger FIDs had a shortened incubation this argumentation seems plausible. period (II). The amount of environmental variation increases the more nest cover and 4.5 Nest-site characteristics are as- nest distance to shore decrease. Incu- sociated with coping style and have bating in open nests exposes females fitness consequences to more direct solar radiation, wind and rain, which may cause heat stress In chapter IV, I investigated if bold- (Fast et al. 2007, Öst et al. 2008a) ness (FID) and stress responsiveness or increase heat loss (Kilpi & Lind- (stress-induced CORT and stress- ström 1997). In addition, nests loca- induced body temperature) are asso- ted closer to the shoreline are more ciated with nest-site selection. I cha- likely to be affected by flooding (cf. racterised nests by their amount of Van de Pol et al. 2010), which may cover and their distance to the closest be responsible for the lower hatchabi- shoreline. Furthermore, I explored if lity of eggs in such nests. Especially female and nest characteristics were in open nests, partial clutch predati- related to the viable proportion of the on on early-laid eggs is high. Nesting clutch, a fitness component. close to the shore increases the like- As the influence of personality lihood of detection by particularly traits on habitat selection has been aerial predators and hence increases highlighted as one of the major the- clutch predation rates at habitat edges mes in personality research (Wolf & (cf. Lloyd et al. 2005). In fact, the Weissing 2012), I hypothesised that mere presence of predators can indu- the boldness and stress responsive- ced continuous psychological stress, ness of female eiders would play an which is related to higher stress res- important role in determining their ponsiveness (Clinchy et al. 2013) and nest-site selection. This hypothesis body temperature (Campeau et al. was supported by my results. Ac- 2008) and can reduces the proportion cordingly, bolder and less stress re- of eggs hatching successfully (Zanet- sponsive individuals occupied more te et al. 2011). Choosing an open nest concealed nests farther from the close to the shore seems to be rather shoreline. counterproductive for current repro- Different personalities may co- duction. However, short-term repro- Personalities in female eiders 35 ductive success is only one compo- or benefit from lower (mammalian) nent of fitness. predation pressure (Spencer 2002). Consistent differences in persona- Nest-site selection had fitness lity traits can arise when those traits consequences which originated from are linked to consistent differences in differences in nest-site characteristics how individuals resolve life-history rather from differences in personality trade-off between reproduction and traits or state of the females. Accor- survival (e.g. Stamps 2007, Wolf et dingly, nests further away from the al. 2007). Productivity and survival shoreline and with intermediate co- cannot be maximized at the same ver had a higher viable proportion of time and indeed, empirical evidence the clutch. The latter finding indicates suggests that proactive individuals the possibility of stabilizing selection give emphasis to higher productivi- acting on nest concealment. But why ty with a concomitantly potential re- did most females nest in sites offering duction in survival rates (reviewed in either very little or high concealment Smith & Blumstein 2008). Probably considering that nests with interme- in line with this trade-off hypothesis diate cover actually produced the is the observed association between highest proportion of hatched young? differences in nest-site characteristics One simple explanation could be that and consistent differences in boldness selection for intermediate nest cover and stress responsiveness in female was rather weak. Furthermore, the eiders. By nesting in covered nests timing of incubation onset was not farther from the shore, bold indivi- associated with the measured habitat duals (shorter FIDs, attenuated stress characteristics (IV), which suggests response) may emphasize clutch sur- that females do not compete for any vival, however, simultaneously ex- special nesting habitat type (cf. Öst et pose themselves to higher predation al. 2008a, Öst & Steele 2010, Ekroos risk. More cover can compromise et al. 2012). the chances of predator detection (cf. The results of chapter IV demonst- Schneider & Griesser 2013) and also rate that personality and stress coping reduce escape opportunities. Fema- styles are related to nest-site choice le eiders nesting in concealed nests and that this relationship seems to be are more easily caught by us (Öst & in line with the trade-off hypothesis Steele 2010), presumably indicating for the evolution of personality (e.g. their greater susceptibility to real pre- Wolf et al. 2007). Furthermore, indi- dation. In shorebirds, higher predati- vidual differences in personality and on mortality in concealed nests has stress coping style may affect fitness been reported before (Amat & Mase- indirectly by breeding habitat selec- ro 2004). Furthermore, shy females tion. Personality types are distributed (longer FIDs, strong stress responses) non-randomly and therefore it is pos- nesting closer to the shore can increa- sible that differential selection acts se their survival rate by escaping fas- on these types (cf. Wolf & Weissing ter to the water (Bentzen et al. 2009) 2012). 36 M.W. Seltmann

5. General conclusions and Another methodological issue is future directions that the studies included in this thesis possibly suffer from a trapping bias. It has been suggested that the exis- 5.1 Unresolved issues tence of personality leads to a bias in When measuring their stress-induced trapping individuals that are overly CORT concentration of female eiders bold (Biro & Dingemanse 2009, Ga- (II, III and IV), we were not able to ramszegi & Török 2009). The shyest follow the standard procedure estab- individuals might not be caught at all, lished by von Holst (1986) and Wing- and thereby studies are at risk of mis- field and colleagues (1992). Based on sing the characterization of the least the nature of our study – particularly bold fraction of the population. This due to ethical considerations – it was is potentially a problem in our study unfortunately not possible to wait population of eiders, where trapping 30 minutes after each bird is caught success can never be perfect. By cat- to obtain maximum stress-induced ching the missing proportion of the CORT concentrations. Blood samp- population, the results of this thesis les at, e.g., 0, 5, 10, 15 and 30 minu- may indeed change. However, be- tes per bird would provide a detailed cause the omission of the least bold stress response curve until its potenti- fraction of the population actually al maximum at 30 minutes. However, tends to make the current results con- the timing of the CORT stress respon- servative and we were still able to se plateau has not yet been investiga- find links between personality and ted in wild female eiders and hence e.g. nest-site choice and fitness, the we cannot say at which time the pla- effect of this sampling bias would be teau is reached. The CORT concent- to underestimate the differences we rations of the second blood samples observed. were affected by the time elapsed A more serious shortcoming of until the second sample, suggesting our data is the question about cause that the plateau was not yet reached. I and effect when investigating nest am nonetheless confident that the in- cover and personality (especially clusion of the covariate ‘time elapsed FID). Nest cover might influence FID from trapping until the second blood or boldness, but it is also conceivab- sample’ in the statistical analysis (II, le that different personalities select III and IV) effectively removed the different nest sites (IV). The two influence of variable sampling times mechanisms might not be mutually of females on our results. While it exclusive and actually reflect a posi- would be highly interesting to define tive feedback between environment the CORT plateau of female eiders, and behaviour. Without experimental the inclusion of absolute maximum manipulations of nest characteristics, CORT concentrations would unlike- this explanation remains speculative ly affect the results or conclusions and it is not possible to infer causality drawn in my work. between female and nest-site charac- Personalities in female eiders 37 teristics. Some support for the idea Finally, as pointed out in chapter I that females with different stress-co- and III, we considered clutch mass as ping styles may differ regarding their a good measurement of reproductive nest-site selection stems from the investment in female eiders because fact that the stress response measures all eggs are produced from stored were determined after removing the reserves and conspecific brood para- female from her nest. Furthermore, sitism (CBP) is relatively infrequent the experimental work by D’Alba in our study population. However, and colleagues (2011) indicate that this last assertion can be challenged. female characteristics may be more Although only 6% of all eggs in our likely to determine the characteristics study population are of non-natal of the nest site rather than the other origin, the fact that 20-22% of clut- way round. Through conducting ex- ches in this population are parasitized periments in which the amount of (Waldeck et al. 2004) means that the nest cover is experimentally reduced proportion of parasitic eggs is consi- or enlarged, it should be possible to derably higher than 6% in those nests reveal causal relationships between that do get parasitized. Assuming that female and nest-site characteristics. brood parasites target hosts randomly Related to this issue is the lacking with respect to their personality and survival analysis of female eiders stress coping style, the occurrence occupying different nest sites. This of CBP should not bias our results. would be crucial to finally determi- However, as suggested in a recent ne the validity of the trade-off hypo- review (Avilés & Parejo 2011), per- thesis explaining personalities (IV). sonality could amongst others be re- However, with only 2 years of over- lated to the risk of brood parasitism. lapping data on FID, stress-induced We also found that the length of the CORT and stress-induced body tem- incubation period was affected by fe- perature, such a survival analysis male boldness (FID) (II). Investiga- would be weak and of little value. ting whether the time period between Interestingly, the findings of laying of the first egg and incubation chapter II demonstrate that the link onset - the time window when CBP between boldness and stress respon- is most likely possible because of the siveness in female eiders runs oppo- host‘s absence from the nest - may site to the conventional definition of depend on the host‘s personality proactive and reactive stress coping traits is therefore an interesting ques- styles (Koolhaas et al. 1999). Addi- tion for further research. tionally to the HPA axis activity one would need to identify the sympatho- 5.2 Future directions adrenomedullary (SAM) activity by Several behaviours maybe modu- measuring the strength of the increase lated by CORT. Pleiotropic effects of catcholamines to ultimately define of hormones are a common mecha- the coping style of eiders and verify nism, and thus the inclusion of other boldness and shyness. 38 M.W. Seltmann behaviours besides boldness such as may offer particularly exciting possi- aggression, dispersal or general ac- bilities to evaluate the adaptive value tivity could bear valuable insights of contrasting stress coping styles into the architecture of personality in different environments, as fema- traits in female eiders. Furthermo- le survival on open islands is lower re, it would be highly interesting to than on forested islands (Ekroos et measure the boldness of females in a al. 2012). In order to adequately eva- context other than reproductive be- luate the long-term relationship bet- haviour. One could then evaluate if ween personality, adult survival and these personality traits are consistent offspring production, one would also not only across time (II), but also need to analyse how female survival across contexts. From a physiologi- depends on nest-site characteristics. cal perspective, studies investigating With additional years of data availab- the potentially interactive effects of le, it should be possible to pursue this different hormonal control mecha- question in the future. nisms on boldness would be espe- Other exciting unexplored ave- cially desirable. As mentioned above, nues for further research are the po- catecholamines should be measured tential link between personality and to determine eider stress coping sty- sociability and that between perso- les, since they seem to run opposi- nality and juvenile survival. Are bold te to the conventional definition of or shy females more or less likely to proactive and reactive stress coping merge with other brood-rearing fe- styles. Catecholamines (e.g., adre- males, affecting the preferred number nalin and noradrenalin), released by of coalition partners in brood-rearing the SAM system, are involved in the coalitions? Female group size, in stress reaction of an animal and are turn, may demonstrably affect the per released into the blood stream even capita survival rate of eider ducklings before GCs. When confronted with a (Öst et al. 2008b). Or is duckling sur- stressor, reactive and bold individuals vival directly dependent on maternal show a high sympathetic reactivity personality? And do bold females (noradrenaline) and a low parasym- prefer bold or shy partners when for- pathetic reactivity (adrenalin), whe- ming brood-rearing coalitions? The reas in reactive and shy individuals mixture of personality types among this pattern is reversed (reviewed in cooperating individuals may be an Koolhaas et al. 1999, Cockrem 2007). important determinant of reproduc- Additionally it is an unresolved tive success, as shown in, e.g., great problem how survival and breeding tits (Both et al. 2005). The eider stu- success, and ultimately lifetime re- dy system in Tvärminne provides an productive success, is shaped by excellent, and perhaps even unique, potential interactions between the opportunity to address these questi- preferred breeding habitat and stress ons. After hatching of the clutch, the coping style (IV). The study populati- females leave with their ducklings to on of eiders investigated in this thesis the sea. Unlike most other eider po- Personalities in female eiders 39 pulations outside the Baltic Sea, whe- se consequences have only received re females and their newly-hatched rudimentary attention so far. Their broods immediately disperse long review however showed that “per- distances from their breeding colo- sonality differences matter” and that nies to feed (Gorman & Milne 1972, they form an “important third dimen- Bustness & Erikstad 1993), females sion of ecologically and evolutiona- at Tvärminne stay close to the bree- ry relevant intraspecific variation” ding islands during most of the post- (Wolf & Weissing 2012). Applying hatch brood-rearing period (Öst & the concept of animal personality for Kilpi 2000). This makes females and addressing practical issues in conser- their clutch relatively easy to observe vation biology (Smith & Blumstein for most of the brood-rearing period 2013) and animal welfare (Hunting- and thereby provides opportunities ford et al. 2013) would be particular- to address the open questions menti- ly welcome, as empirical research is oned above. still lagging behind the expectations On a more general note, resear- expressed. chers should finally agree on one common framework and a common 5.3 Concluding remarks nomenclature in the near future, in The findings of chapterI and III show order for animal personality research that serum and faecal baseline CORT to continue to thrive as a top bran- as well as the acute CORT reactivity ch of ecological and evolutionary are related to fitness in female eiders. research. Several frameworks have Importantly, these relationships were been proposed recently (e.g. Réa- always context dependent. CORT- le et al. 2007, Réale et al. 2010a, b, fitness relationships were modulated Carter et al. 2013). However, a com- by internal individual quality and by mon framework of animal persona- external environmental stimuli. This lity is still not implemented, which context dependency might be an ex- often makes it difficult to compare planation why earlier studies have studies that supposedly measure the found positive, negative or neutral same personality trait, but actually associations between CORT and fit- assess different behaviours (Carter et ness. The results highlight the sig- al. 2012). Likewise, McNamara and nificance of scrutinizing the degree Houston (2009) have recently propo- of environmental challenge and the- sed that a common framework that reby contribute to bridging the gap integrates function and mechanisms between the sometimes incongruent is elementary for the future progress views on these important but elusi- of personality research in behaviou- ve relationships. The repeatability of ral ecology. Although the review by baseline CORT (I) showed that the Wolf and Weissing (2012) presented CORT-fitness hypothesis was gene- 14 important consequences that con- rally supported in female eiders. In sistent individual behaviour has on chapter II I illustrated that CORT ecology and evolution, many of the- 40 M.W. Seltmann stress responsiveness and boldness sonality research (Wolf & Weissing (FID) correlate in female eiders. 2012). In chapter IV, I provided one The correlational nature of FID and of the first demonstrations that mater- stress-induced CORT has been shown nal boldness and stress responsiven- before in other species (e.g., Thaker ess are associated with, and possib- et al. 2010, Atwell et al. 2012). How- ly even responsible for, variation in ever, in this thesis, I emphasize the nest-site selection. Perhaps the gre- interactive nature of this correlation atest novelty value of the study lies showing that it can be modulated by in illustrating how personality and individual quality such as maternal coping style can explain variation in experience and body condition. nest-site choice in the context of the The effects of personality traits on trade-off hypothesis for the evolution habitat selection have been highligh- of personality (Wolf et al. 2007). ted as one of the major themes in per- Personalities in female eiders 41

6. Acknowledgements and you all have contributed to this thesis by spending a big part of your There are many people I would like time in the field and lab to collect this to express my gratitude to. First of all tremendous amount of data. Thanks! and especially, I want to thank Mar- I want to thank my professor Kai kus for giving me the opportunity Lindström for his valuable help and to work on an exciting topic in such advice in managing the bureaucra- great places like Finland and Alaska. tic matters of a PhD thesis and his You were always very supportive and straightforward style of communica- patient and when knocking at your tion. door you always had some helpful Sincere thanks to the members of comments. Your impressive German my thesis support group, Jon Brom- skills (“Quatsch!”) as well as your mer and Heikki Helanterä. We had excellent dancing skills saved many very good meetings, where you hel- days in the field. I really enjoyed ob- ped me to put my past progress into serving eiders at Tvärminne and it perspective, and to realize what had sparked my interest in doing some to be done next. You gave me essen- actual bird watching. It is quite im- tial advice in scientific and organiza- pressive how eager, calm and profes- tional matters. sional you are when doing your work. My gratitude goes to Tvärmin- It needed an invasion by the Finnish ne Zoological Station and its always Army to turn you into the Incredible friendly and very helpful staff. I Hulk. acknowledge that it must be a hard Secondly, my thanks go to Kimi time to tolerate a bunch of extreme- for your considerable help with all ly smelly people during the lunch sorts of issues around my PhD work. breaks. My next “Thank you” goes Discussing statistics and scientific across the great pond to the beautiful problems was always a pleasure and State of Alaska where I met a lot of helped me to improve my skills with wonderful people. Thanks Tuula for analysing data and critical thinking. I preparing and establishing the coope- especially recognized the importance ration between the eider group in Fin- of interactions, between variables and land and the Atkinson lab in Juneau. colleagues. Thank you! Thanks Shannon for giving me the Furthermore, I want to thank the opportunity to work in your lab and former members of the eider team, for your helpful comments (and the Aleksi Lehikoinen and Johan Ekroos lab parties). Thanks Kendall for your for the great work they did and all invaluable help and advice in how to their help. I am also grateful to all the run RIAs and extracting CORTs from long- and short-term members of the eider poop (and for the great Thanks- field crew: Ben, Pepe, Heikki, Marjo, giving party). Thanks Angie for hel- Anna, Andrea, Julia, Kristina, Sara, ping me with all kinds of organizatio- Colby, Phil and Jimmy. Working with nal efforts to make my travel and stay you guys in the field was great fun in Juneau smooth and sound. I also 42 M.W. Seltmann want to thank Angie’s family (Ralph, ne, Jonna, Johan, Patrik, Anssi, Lau- Sara, James and Tiger) for all the nice ri, Satu, Ane, Patte, Andreas, Romi, dinners and evenings that made my Sonja, Tuomas, Pua, Rolf, Kaj, Ul- stay in Alaska so comfortable, I al- rika, Mika, Eli (we won’t get fooled ways felt very welcome at your place. again!), Andreas (co-founder of the Thanks! I hope I’ll be able to come Tammisaari pipe club), Traci (mem- back to Juneau sometimes. ber of the geek/PhD student office), I very much appreciate the time- Anu, Tiina, Mari, Malin, Anna-Karin, ly effort made by the pre-examiners Lasse, Pieter, Kajsa and Jenny. I also of this thesis, Hannu Pöysä and Kees want to thank all the friends and col- van Oers. Thank you very much for leagues from Helsinki and Turku for your valuable comments on the ear- always being great company, Alex, ly version of the thesis and for kee- Ed, Claire, Eva, Diego, Daniel, Ben, ping the tight schedule I asked you Tamas, Megha, Bineet, Siim, Camil- for. I am also deeply grateful to Niels la, Anna, and many more. Dingemanse, who agreed to read my Many thanks to all my friends thesis, travel to Finland and act as my back home in the Oberpfalz and in opponent. Germany, it is always great to come I have been fortunate to participate back and hang out with you folks, just in the BIOINT graduate school. The like in “the good old days”. Some of school organized interesting courses you even made the trip to Finland to and the annual meetings were a great visit me. Surely you were shocked happening to meet PhD students from by the beer prices, but we had great different fields and exchange ideas. times anyway. Thanks for coming up Thanks to the coordinator of the to the North. school Anne, who did a great job in Much gratitude goes to my pa- organizing all the different BIOINT rents, Annemarie and Dietmar, and events. I also want to thank the co- my brother Oli and his family, Ve- ordinator of the LUOVA graduate rena, Paul and Emma. Your support school, Anni, who organised great has always been highly valuable to courses and was always very helpful. me, thank you so much! I also want I am grateful to the funding agen- to thank Leena and Jarmo for welco- cies and organisations that made this ming me and taking me to all sorts of research possible: the Academy of trips, be it opera visits or skiing in La- Finland, the Onni Talas Foundation pland. Finally, I want to thank Anna and Åbo Akademi University. for the never-ending support she gave For the last four and a half years, me through all stages of my PhD the- Aronia has been a pleasant place to sis and for all the great times we have work at. Many thanks to all my col- together. leagues, Wille, Mika, Ulrica, Marian- Personalities in female eiders 43

7. Literature cited Angelier, F. & Wingfield, J.C. 2013. Importance of the glucocorticoid stress response in a changing Albrecht, T. & Klvaňa, P. 2004. Nest world: Theory, hypotheses and per- crypsis, reproductive value of a spectives. General and Comparati- clutch and escape decisions in ve Endocrinology, 190, 118–128. incubating female mallards Anas platyrhynchos. Ethology, 110, Atwell, J.A., Cardoso, G.C., Whit- 603–613. taker, D.J., Campbell-Nelson, S., Robertson, K.W. & Ketterson, Amat, J.A. & Masero, J.A. 2004. Pre- E.D. 2012. Boldness behavior and dation risk on incubating adults stress physiology in a novel urban constrains the choice of thermally environment suggest rapid corre- favourable nest sites in a plover. lated evolutionary adaptation. Be- Animal Behavior, 67, 293–300. havioral Ecology, 23, 960–969. Angelier, F., Weimerskirch, H., Dano, Avilés, J.M., Parejo, D. 2011. Host S. & Chastel, O. 2007a. Age, ex- personalities and the evolution of perience and reproductive per- behavioural adaptations in brood formance in a long-lived bird: a parasitic-host systems. Animal hormonal perspective. Behavioral Behaviour, 82, 613–618. Ecology and Sociobiology, 61, 611–621. Baugh, A.T., Schaper, S.V., Hau, M., Cockrem, J.F., de Goede, P. & Angelier, F., Moe, B., Weimerskirch, van Oers, K. 2012. Corticosterone H. & Chastel, O. 2007b. Age- responses differ between lines of specific reproductive success in a great tits (Parus major) selected long-lived bird: do older parents for divergent personalities. Gene- resist stress better? Journal of Ani- ral and Comparative Endocrinolo- mal Ecology, 76, 1181–1191. gy, 175, 488–494. Angelier, F., Holberton, R. & Mar- Baugh, A.T., van Oers, K. Naguib, ra, P. 2009. Does stress response M. & Hau, M. 2013. Initial reac- predict return rate in a migrato- tivity and magnitude of the acute ry species? A study of American stress response associated with redstarts and their non-breeding personality in wild great tits (Pa- habitat. Proceedings of the Royal rus major). General and Compara- Society B, 276, 3545–3551. tive Endocrinology, 189, 96–104. Angelier, F., Wingfield, J.C., Wei- Bell, A.M. 2007. Future directions in merskirch, H. & Chastel, O. 2010. behavioural syndromes research. Hormonal correlates of individu- Proceedings of the Royal Society al quality in a long-lived bird: a of London B, 274, 755–761. test of the ‘corticosterone-fitness hypothesis’. Biology. Letters, 6, Bell, A.M., Hankison, S.J., Laskow- 846–849. ski, K.L. 2009. The repeatabili- 44 M.W. Seltmann

ty of behaviour: a meta-analysis. Blas, J., Bortolotti, G.R., Tella, J.L., Animal Behaviour, 77, 771–783. Baos, R. & Marchant, T.A. 2007. Stress response during develop- Bentzen, R.L., Powell, A.N. & Suy- ment predicts fitness in a wild, dam, R.S. 2009. Strategies for long-lived vertebrate. Procee- nest-site selection by king eiders. dings of the National Academy of Journal of Wildlife Management, Sciences USA of the 104, 8880– 73, 932–938. 8884. Benus, R.F., Bohus, B., Koolhaas, Bókony, V., Lendvai, A.Z., Liker, J.M. & van Oortmerssen, G.A. A., Angelier, F., Wingfield, J.C. & 1991. Heritable variation in ag- Chastel, O. 2009. Stress response gression as a reflection of indivi- and the value of reproduction: are dual coping strategies. Experien- birds prudent parents? American tia, 47, 1008–1019. Naturalist, 173, 589–598. Bergmüller, R. & Taborsky, M. Bolduc, F. & Guillemette, M. 2010. Animal personality due to 2003a. Incubation constancy and social niche specialization. Trends mass loss in the common eider in Ecology and Evolution, 25, Somateria mollissima. Ibis, 145, 504–511. 329–332. Biro, P.A. & Post, J.R. 2008. Rapid Bonier, F., Martin, P.R., Moore, depletion of genotypes with fast I.T. & Wingfield, J.C. 2009a. Do growth and bold personality traits baseline glucocorticoids predict from harvested fish populations. fitness? Trends in Ecology & Evo- Proceedings of the National Aca- lution, 24, 634−642. demy of Sciences of the U.S.A., 105, 2919–2922. Bonier, F., Moore, I.T., Martin, P.R. & Robertson, R.J. 2009b. Biro, P.A. & Stamps, J.A. 2008. Are The relationship between fitness animal personality traits linked to and baseline glucocorticoids in life-history productivity? Trends a passerine bird. General and in Ecology and Evolution, 23, Comparative Endocrinology, 163, 361–368. 208−213. Biro, P.A. & Dingemanse, N.J. 2009. Boon, A.K., Réale, D. & Boutin, S. Sampling bias resulting from ani- 2008. Personality, habitat use, and mal personality. Trends in Ecolo- their consequences for survival gy and Evolution, 24, 66–67. in North American red squirrels Biro, P.A. &Stamps, J.A. 2010. Do Tamiasciurus hudsonicus. Oikos, consistent individual differences 117, 1321−1328. in metabolic rate promote con- Both, C., Dingemanse, N.J., Drent, sistent individual differences in P.J. & Tinbergen, J.M. 2005. Pairs behavior? Trends in Ecology and of extreme avian personalities Evolution, 25, 653–659. Personalities in female eiders 45

have highest reproductive suc- of Comparative Physiology Part cess. Journal of Animal Ecology, B, 182,403−414. 74, 667−674. Carere, C., Groothuis, T.G.G., Breuner, C.W., Patterson, S.H. & Möstl, E., Daan, S. & Koolhaas, Hahn, T.P. 2008. In search of re- J.M. 2003. Fecal corticosteroids lationships between the acute ad- in territorial bird selected for dif- renocortical response and fitness. ferent personalities: daily rhythm General and Comparative Endo- and the response to social stress. crinology, 157, 288–295. Hormones and Behavior, 43, 540– 548. Bustnes, J.O. & Erikstad, K.E. 1991. Parental care in the common eider Carere, C., Caramaschi, D. & Faw- (Somateria mollissima): factors cett, T.W. 2010. Covariation bet- affecting abandonment and adop- ween personalities and individual tion of young. Canadian Journal differences in coping with stress: of Zoology, 69, 1538–1545. Converging evidence and hypothesis. Current Zoology, 56, 728−740. Bustnes, J.O. & Erikstad, K.E. 1993. Site fidelity in breeding common Carere, C. & Maestripieri, D. 2013. eider Somateria mollissima fema- Animal Personalities. Behaviour, les. Ornis Fennica, 70, 11–16. physiology, and evolution. The University of Chicago Press, Chi- Cabanac, M. 2006. Adjustable set cago. point: to honor Harold T. Ham- mel. Journal of Applied Physiolo- Carrete, M. & Tella, J.L. 2010. Indi- gy, 100, 1338–1346. vidual consistency in flight initiation distances in burrowing owls: Campeau, S., Nyhuis, T.J., Sas- a new hypothesis on disturbance se, S.K., Day, H.E.W. & Masini, induced habitat selection. Biology C.V. 2008. Acute and chronic ef- Letters, 6, 167–170. fects of ferret odor exposure in Sprague–Dawley rats. Neurosci- Carter, A.J., Goldizen, A.W. & ence &. Biobehavioral Reviews, Tromp, S.A. 2010. Agamas exhi- 32, 1277–1286. bit behavioural syndromes: bolder males bask and feed more but may Careau, V., Thomas, D., Humphries, suffer higher predation. Behavio- M.M. & Réale, D. 2008. Energy ral Ecology, 21, 655–661. metabolism and animal personality. Oikos, 117, 641–653. Carter, A.J., Marshall, H.H., Hein- sohn, R. & Cowlishaw, G. 2012. Careau, V., Réale, D., Garant, D., How not to measure boldness: Speakman, J.R. & Humphries, novel object and antipredator re- M.M. 2012. Stress-induced rise sponses are not the same in wild in body temperature is repeatab- baboons. Animal Behaviour, 84, le in free-ranging Eastern chip- 603–609. munks (Tamias striatus). Journal 46 M.W. Seltmann

Carter, A.J., Feeney, W.E., Marshall, sonalities. Journal of Ornithology, H.H., Cowlishaw, G. & Heinsohn, 148, S169–S178. R. 2013. Animal personality: what Cockrem, J.F., Barrett, D.P., Candy, are behavioural ecologists measu- E.J. & Potter, M.A. 2009. Corti- ring? Biological Reviews, 88, costerone responses in birds: Indi- 465–475. vidual variation and repeatability Champoux, M., Bennett, A., Shan- in Adelie penguins (Pygoscelis non, C., Higley, J.D., Lesch, K.P. adeliae) and other species, and & Suomi, S.J. 2002. Serotonin the use of power analysis to de- transporter gene polymorphism, termine sample sizes. General and differential early rearing, and Comparative Endocrinology, 163, behavior in rhesus monkey neo- 158–168. nates. Molecular Psychiatry , 7, Coleman, K. & Wilson, D.S. 1998. 1058–1063. Shyness and boldness in pump- Clark, A.B. & Ehlinger T.J. 1987. kinseed sunfish: individual diffe- Pattern and adaptation in indivi- rences are context-specific. Ani- dual behavioural differences. In: mal Behaviour, 56, 927–936. Bateson, P.P.G. & Klopfer, P.H. Coppens, C.M., de Boer, S.F. & (eds) Perspectives in Ethology. Koolhaas, J.M. 2010. Coping Plenum Press, NY. styles and behavioural flexibility: Clark, C.W. 1994 Antipredator be- towards underlying mechanisms. havior and the asset-protection Philosophical Transactions of principle. Behavioral Ecology, 5, the Royal Society B, 365, 4021– 159–170. 4028. Clinchy, M., Sheriff, M.J. & Za- Criscuolo, F., Bertile, F., Durant, nette, L. 2013. Predator induced J.M., Raclot, T., Gabrielsen, G.W., stress and the ecology of fear. Massemin, S. & Chastel, O.2006. Functional Ecology, 27, 56–65. Body mass and clutch size may modulate prolactin and corticoste- Cockrem, J.F. & Silverin, B. 2002. rone levels in eiders. Physiologi- Variation within and between cal and Biochemical Zoology, 79, Birds in Corticosterone Respon- 514–521. ses of Great Tits (Parus major). General and Comparative Endo- Crossin, G.T., Trathan, P.N., Phil- crinology, 125, 197–206. lips, R.A., Gorman, K.B., Daw- son, A., Sakamoto, K.Q. & Wil- Cockrem, J.F. 2005. Conservation liams, T.D. 2012. Corticosterone and behavioral neuroendocrino- predicts foraging behavior and logy. Hormones & Behavior, 48, parental care in macaroni pen- 492–501. guins. American Naturalist, 180, Cockrem, J.F. 2007. Stress, cortico- E31–41. sterone responses and avian per- Personalities in female eiders 47

D‘Alba, L., Spencer, K.A., Nager, selection maintains variation in R.G. & Monaghan, P. 2011. Sta- animal personalities? In: Carere, te dependent effects of elevated C. & Maestripieri, D. (eds) Animal hormones: Nest site quality, corti- personalities. Behavior, physiolgy, costerone levels and reproductive and evolution. The University of performance in the common eider. Chicago Press, Chicago. General and Comparative Endo- Dugatin, L.A. 1997. Winner and lo- crinology, 172, 218–224. ser effects and the structure of do- Dall, S.R.X. 2004. Behavioural bio- minance hierarchies. Behavioral logy: Fortune favours bold and Ecology, 8, 583–587. shy personalities. Current Biolo- Ekroos, J., Öst, M., Karell, P., Jaa- gy, 14, R470–R472. tinen, K. & Kilpi, M. 2012. Phi- Dall, S.R.X., Houston, A.I.H. & lopatric predisposition to preda- McNamara, J.M. 2004. The be- tion-induced ecological traps: havioural ecology of personality: habitat-dependent mortality of consistent individual differences breeding eiders. Oecologia, 170, from an adaptive perspective. 979–86. Ecology Letters, 7, 734–739. Evans, M.R., Roberts, M.L., Descamps, S., Gilchrist, H.G., Bety Buchanan, K.L. & Goldsmith, J., Buttler, E.I. & Forbes, M.R. A.R. 2006. Heritability of corti- 2009. Costs of reproduction in a costerone response and changes in long-lived bird: large clutch size life history traits during selection is associated with low survival in in the zebra finch. Journal of Evo- the presence of a highly virulent lutionary Biology, 19, 343–352. disease. Biology Letters, 5, 278– Fast, P.L., Gilchrist, F.H. G. & Clark, 281. R.G. 2007. Experimental evaluati- Dingemanse, N.J., Both, C., Drent, on of nest shelter effects on weight P.J. & Tinbergen, J.M. 2004. loss in incubating common eiders Fitness consequences of avian Somateria mollissima. Journal of personalities in a fluctuating en- Avian Biology, 38, 205–213. vironment. Proceedings of the Fidler, A.E., van Oers, K., Drent, Royal Society of London B, 271, P.J., Kuhn, S., Mueller, J.C. & 847–852. Kempenaers, B. 2007. Drd4 gene Dingemanse, N.J., Edelaar, P. & polymorphisms are associated Kempenaers, B. 2010. Why is the- with personality variation in a re variation in baseline glucocor- passerine bird. Proceedings of the ticoid levels? Trends in Ecology Royal Society of London B, 274, and Evolution, 25, 261–262. 1685–1691. Dingemanse, N.J. & Réale, D. 2013. Forbes, M.R.L., Clark, R.G., Wea- What is the evidence that natural therhead, P.J. & Armstrong, T. 48 M.W. Seltmann

1994. Risk-taking by female start and egg size in relation to ducks: intra- and interspecific body reserves in the common ei- tests of nest defense theory. Beha- der. Behavioral Ecology and So- vioral Ecology and Sociobiology, ciobiology, 52, 282–288. 34, 79–85. Hayward, L.S. & Wingfield, J.C. Garamszegi, L.Z. & Török, J. 2009. 2004. Maternal corticosterone is Behavioural syndromes and transferred to avian yolk and may trappability in free-living collared alter offspring growth and adult flycatchers, Ficedula albicollis. phenotype. General and Compa- Animal Behaviour, 77, 803–812. rative Endocrinology, 135, 365– 371. Giraldeau, L.A. & Beauchamp, G. 1999. Food exploitation: se- Heidinger, B.J., Nisbet, I.C.T. & arching for the optimal joining Ketterson, E.D. 2006. Older pa- policy. Trends in Ecology and rents are less responsive to a Evolution, 14, 102–106. stressor in a long-lived seabird: a mechanism for increased repro- Gladbach, A., Gladbach, D.J., Koch, ductive performance with age? M., Kuchar, A., Möstl, E. & Quill- Proceedings of the Royal Society feldt, P. 2011. Can faecal gluco- B, 273, 2227–2231. corticoid metabolites be used to monitor body condition in wild Hudson, R., Maqueda, B., Moctezu- Upland geese Chloephaga picta ma, J.V., Miranda, A.M. & Rödel, leucoptera? Behavioral Ecology H.G. 2011. Individual differences and Sociobiology, 65, 1491–1498. in testosterone and corticosterone levels in relation to early postnatal Gorman, M.L. & Milne, H. 1972. development in the rabbit Oryc- Crèche behaviour in the Com- tolagus cuniculus. Physiology & mon Eider. Omis Scandinavia, 3, Behavior, 103, 336–341. 21–25. Huntingford, F.A. 1976. The rela- Goutte, A., Antoine, É., Weimers- tionship between anti-predator kirch, H. & Chastel, O. 2010. Age behaviour and aggression among and the timing of breeding in a conspecifics in the three-spined long-lived bird: a role for stress stickleback. Animal Behaviour, hormones? Functional Ecology, 24, 245–260. 24, 1007–1016. Huntingford, F., Mesquita, F. & Ka- Groothuis, T.G.G. & Carere, C. dri, S. 2013. Personality variation 2005. Avian personalities: charac- in cultured fish: implications for terization and epigenesist. Neu- production and welfare. In: Ca- roscience and Biobehavioral Re- rere, C. & Maestripieri, D. (eds) views, 29, 137–150. Animal personalities. Behavior, Hanssen, S.A., Engebretsen, H. & physiolgy, and evolution. The Uni- Erikstad, K.E., 2002 Incubation versity of Chicago Press, Chicago. Personalities in female eiders 49

Jaatinen, K. & Öst, M. 2011. Experi- physiological correlates of per- ence attracts: the role of age in the sonality in greylag geese (Anser formation of cooperative brood- anser). Journal of Ethology, 28, rearing coalitions in eiders. Ani- 363–370. mal Behaviour, 81, 1289–1294. Lehikoinen, A., Jaatinen, K. & Öst, Jaatinen, K., Öst, M. & Lehikoinen, M. 2010. Do female ornaments in- A. 2011. Adult predation risk dri- dicate quality in eider ducks? Bio- ves shifts in parental care strate- logy Letters, 6, 225–228. gies: a long-term study. Journal of Lendvai, A.Z., Giraudeau, M. & Animal Ecology, 80, 49–56. Chastel. O. 2007. Reproduction Kilpi, M. & Lindström, K. 1997. and modulation of the stress res- Habitat-specific clutch size and ponse: an experimental test in the cost of incubation in common ei- house sparrow. Proceedings of the ders, Somateria mollissima. Oeco- Royal Society B: Biological Sci- logia, 111, 297–301. ences, 274, 391–397. Kilpi, M., Öst, M., Lindström, K. & Lindström, M. 2003 Register över Rita, H. 2001. Female characteris- öar, holmar, kobbar och skär i tics and parental care mode in the Tvärminneområdet. Nordenski- crèching system of eiders, Soma- öld-samfundets tidskrift, 62, 3–49. teria mollissima. Animal Behavi- Love, O.P. & Williams, T.D. 2008. our, 62, 527–534. Plasticity in the adrenocortical re- Koolhaas, S.M., Korte, S.M., de sponse of a free-living vertebrate: Boer, S.F., van der Vegt, B.J., The role of pre- and post-natal de- van Reenen, C.G., Hopster, H., velopmental stress. Hormones and de Jong, I.C., Ruis, M.A.W. & Behavior, 54, 496–505. Blokhuis, H.J. 1999. Coping sty- Lloyd, P., Martin, T.E., Redmond, les in animals: current status in R.L., Langner, U. & Hart, M.M. behaviour and stress-physiology. 2005. Linking demographic ef- Neuroscience and Biobehavioral fects of habitat fragmentation Reviews, 23, 925–935. across landscapes to continental Kralj-Fišer, S., Scheiber, I.B.R., source–sink dynamics. Ecological Blejec, A., Moestl, E. & Ko- Applications, 15, 1504–1514. trschal, K. 2007. Individualities Luttbeg, B. & Sih, A. 2010. Risk, in a flock of free-roaming greylag resources and state-dependent geese: Behavioral and physiolo- adaptive behavioural syndromes. gical consistency over time and Philosophical Transactions of the across situations. Hormones and Royal Society B, 365, 3977–3990. Behavior, 51, 239–248. Malmkvist, J. & Hansen, S. W. Kralj-Fišer, S., Weiß, B.M. & Ko- 2002. Generalization of fear in trschal, K. 2010. Behavioural and farm mink, Mustela vison, ge- 50 M.W. Seltmann

netically selected for behaviour guide for biologists. Biological towards humans. Animal Behavi- Reviews, 85, 935–956. our, 64, 487–501. Nicolaus, M., Tinbergen, J.M., Bou- Martin, P. & Bateson, P. 1986. wman, K.M., Michler, S.P.M., Measuring Behaviour: An intro- Ubels, R., Both, C., Kempenaers, ductory guide. Cambridge Uni- B. & Dingemanse, N.J. 2012. Ex- versity Press, Cambridge. perimental evidence for adaptive personalities in a wild passerine Martin, T.M. & Schwabl, H. 2008. bird. Proceedings of the Royal So- Variation in maternal effects and ciety B, 279, 4885–4892. embryonic development among passerine bird species. Philoso- Nilsson, P.B. 2004. Characterizing phical Transactions of the Royal glucocorticoid levels in five spe- Society B, 363, 1663–1674. cies of sea ducks occurring in Alaska. Master thesis, University Martins, T.L.F., Roberts, M.L., of Alaska Fairbanks. Giblin, I., Huxham, R. & Evans, M.R. Speed of exploration and Oka, T., Oka, K. & Hori, T. 2001. risk-taking behavior are linked to Mechanisms and mediators of corticosterone titres in zebra fin- psychological stress-induced rise ches. Hormones and Behavior, 52, in core temperature. Psychosoma- 445–453. tic Medicine, 63, 476–486. McNamara, J.M. & Houston, A.I. Osiejuk, T.S. & Kuczyński, L. 2007. 2009. Integrating function and Factors affecting flushing distance mechanism. Trends in Ecology in incubating female greylag gee- and Evolution, 24, 670–675. se Anser anser. Wildlife Biology, 13, 11–18. Meerlo, P, De Boer, S.F., Koolhaas, J.M. Daan, S. & Van den Hoofdak- Öst, M. & Kilpi, M. 2000. Eider fe- ker, R.H., 1996. Changes in daily males and broods from neighboring rhythms of body temperature and colonies use segregated local fee- activity after a single social defeat ding areas. Waterbirds, 23, 24–32. in rats. Physiology & Behavior, Öst, M., Wickman, M., Matulionis, 59, 735–739. E. & Steele, B.B. 2008a. Habitat- Möstl, E., Rettenbacher, S., Palme, specific clutch size and cost of R., 2005. Measurement of corti- incubation in eiders reconsidered. costerone metabolites in birds‘ Oecologia. 158, 205−216. droppings: an analytical approach. Öst, M., Smith, B.D. & Kilpi, M. Annals of the New York Academy 2008b. Social and maternal fac- of Sciences, 1046, 17−34. tors affecting duckling survival Nakagawa, S. & Schielzeth, H. in eiders Somateria mollissima. 2010. Repeatability for Gaussian Journal of Animal Ecology, 77, and non-Gaussian data: a practical 315–325. Personalities in female eiders 51

Öst, M. & Steele, B.B. 2010. Age- computing. R Foundation for Stati- specific nest-site preference and stical Computing, Vienna, Austria. success in eiders. Oecologia, 162, URL http://www.R-project.org/. 59–69. Réale, D., Reader, S. M., Sol, D., Öst, M., Lehikoinen, A., Jaatinen, McDougall, P. T. & Dingemanse, K. & Kilpi, M. 2011. Causes and N. J. 2007. Integrating animal consequences of fine-scale bree- temperament within ecology and ding dispersal in a female-philo- evolution. Biological Reviews, patric species. Oecologia, 166, 82, 291–318. 327–336. Réale, D., Martin, J., Coltman, Parker, H. & Holm, H. 1990. Pat- D.W., Poissant, J. & Festa-Bian- terns of nutrient and energy ex- chet, M. 2009. Male personality, penditure in female common life-history strategies and repro- eiders nesting in the high arctic. ductive success in a promiscuous Auk. 107, 660−668. mammal. Journal of Evolutionary Biology, 22, 1599–1607. Purnell, J.Q., Brandon, D.D., Isa- bella, L.M., Loriaux, D.L. & Sa- Réale, D., Dingemanse, N.J., Ka- muels, M.H. 2004. Association zem, A.J.N. & Wright, J. 2010a. of 24-hour cortisol production Evolutionary and ecological ap- rates, cortisol-binding globulin, proaches to the study of persona- and plasma free cortisol levels lity. Philosophical Transactions of with body composition, leptin le- the Royal Society B, 365, 3937– vels, and aging in adult men and 3946. women. The Journal of Clinical Réale, D., Garant, D., Humphries, Endocrinology & Metabolism, 89, M.M., Bergeron, P., Careau, V. & 281–287. Montiglio, P.-O. 2010b. Personali- Quinn, J.L. & Cresswell, W. 2005. ty and the emergence of the pace- Personality, anti-predation beha- of-life syndrome concept at the viour and behavioural plasticity population level. Philosophical in the chaffinch Fringilla coelebs. Transactions of the Royal Society Behaviour, 142, 1377–1402. B, 365, 4051–4063. Quinn, J.L., Patrick, S.C., Bou- Rensel, M.A. & Schoech, S.J. 2011. whuis, S., Wilkin, T.A. & Shel- Repeatability of baseline and don, B.C. 2009. Heterogeneous stress-induced corticosterone le- selection on a heritable tempera- vels across early life stages in the ment trait in a variable environ- Florida scrub-jay (Aphelocoma ment. Journal of Animal Ecology, coerulescens). Hormones and Be- 78, 1203–1215. havior, 59, 497–502. R Core Team. 2013. R: A langua- Ricklefs, R.E. & Wikelski, M. 2002. ge and environment for statistical The physiology-life-history ne- 52 M.W. Seltmann

xus. Trends in Ecology and Evo- gent stress coping strategies in ju- lution, 17, 462–468. venile rainbow trout? Physiologi- cal and Biochemical Zoology, 78, Romero, L.M. 2002. Seasonal chan- 715–723. ges in plasma glucocorticoid concentrations in free-living verteb- Schmidt, J.B., Andreé, R.M., Davis, rates. General and Comparative K.A., Treese, S.M. & Satterlee, Endocrinolology, 128, 1–24. D.G. 2009. Influence of maternal corticosterone treatment on Romero, L.M. & Reed, J.M. Re- incubation length of eggs laid by peatability of baseline corticoste- Japanese quail hens selected for rone concentrations. General and divergent adrenocortical stress re- Comparative Endocrinology, 156, sponsiveness. British Poultry Sci- 27–33. ence, 50, 739–747. Rubolini, D., Romano, M., Bonco- Schneider, N.A. & Griesser, M. 2013. raglio, G., Ferrari, R.P., Martinel- Incubating females use dynamic li, R., Galeotti, P., Fasola, M. & risk assessment to evaluate the risk Saino, N. 2005. Effects of eleva- posed by different predators. Beha- ted egg corticosterone levels on vioral Ecology, 24, 47–52. behavior, growth and immunity of yellow-legged gull (Larus micha- Schuett, W., Tregenza, T. & Dall, hellis) chicks. Hormones and Be- S.R.X. 2010. Sexual selection and havior, 47, 592–605. animal personality. Biological Re- views, 85, 217–246. Saino, N., Romano, M. Ferrari, R.P., Marinelli, R. & Møller, A.P. 2005. Sih, A., Bell, A. & Johnson, J.C. Stressed mothers lay eggs with 2004a. Behavioral syndromes: an high corticosterone levels which ecological and evolutionary over- produce low-quality offspring. view. Trends in Ecology and Evo- Journal of Experimental Zoology lution, 19, 372–378. Part A: Comparative Experimen- Sih, A., Bell, A.M., Johnson, J.C. & tal Biology, 303, 998–1006. Ziemba, R.E. 2004b. Behavioral Sapolsky, R.M., Romero, L.M. & syndromes: an integrative over- Munck, A.U. 2000. How do glu- view. The Quarterly Review of cocorticoids influence stress res- Biology, 79, 241–277. ponses? Integrating permissive, Sluyter, F., Jamot, L., van Oort- suppressive, stimulatory, and pre- merssen, G.A. & Crusio, W.E. parative actions. Endocrine Re- 1994. Hippocampal mossy fiber views, 21, 55–89. distributions in mice selected for Schjolden, J., Stoskhus, S. & Win- aggression. Brain Research, 646, berg, S. 2005. Does individual 145–148. variation in stress responses and Smith, B.R. & Blumstein, D.T. agonistic behavior reflect diver- 2008. Fitness consequences of Personalities in female eiders 53

personality: a meta-analysis. Be- vel stressor. American Naturalist, havioral Ecology, 19, 448–455. 175, 50–60. Smith, B.R. & Blumstein, D.T. Tinbergen, N. 1963. On aims and 2013. Animal personality and methods of ethology. Zeitschrift conservation biology: the impor- für Tierpsychologie, 20, 410-433. tance of behavioural diversity. Van de Pol, M., Ens, B.J., Heg, D., In: Carere, C. & Maestripieri, D. Brouwer, L. Krol, J., Maier, M., (eds) Animal personalities. Be- Exo, K.-M., Oosterbeek, K., Lok, havior, physiolgy, and evolution. T., Eising, C.M. & Koffijberg, The University of Chicago Press, K. 2010: Do changes in the fre- Chicago. quency, magnitude and timing of Sokal, R.R. & Rohlf, F.J. 1995. Bio- extreme climatic events threaten metry: The priciples and practice the population viability of coastal of statistics in biological research. birds? Journal of Applied Ecolo- W.H. Freeman and Company, gy, 47, 720–730. New York, USA. Von Holst, D. 1986. Psychosocial Spencer, R.-J. 2002. Experimentally stress and its pathophysiological testing nest site selection: fitness effects in tree shrews (Tupaia be- trade-offs and predation risk in langeri). In: Schmidt, T.H., Dem- turtles. Ecology, 83, 2136–2144. broski, T.M. & Blümchen, G. (eds) Biological and Psychological Fac- Stamps, J.A. 2007. Growth-mortali- tors in Cardiovascular Disease. ty tradeoffs and ‘personality traits’ Springer Verlag Berlin Heidelberg. in animals. Ecology Letters, 10, 355–363. Von Holst, D. 1998. The concept of stress and its relevance for animal Stearns, S. 1992. The Evolution of behavior. Advances in the Study Life Histories. Oxford University of Behavior, 27, 1–131. Press, NY. Van Oers, K., Drent, P.J., de Goede, Stein-Behrens, B. & Sapolsky, R.M. P. & van Noordwijk, A.J. 2004. 1992. Stress, glucocorticoids, and Realized heritability and repea- aging. Aging Clinical and Experi- tability of risk-taking behaviour mental Research, 4, 197–210. in relation to avian personalities. Talbot, L.R. 1922. Bird-banding at Proceedings of the Royal Society Thomasville, Georgia, in 1922. of London B, 271, 65–73. Auk, 39, 334–350. Van Oers, K., Klunder, M. & Drent, Thaker, M., Vanak, A.T., Lima, S.L. P.J. 2005. Context dependence of & Hews, D.K. 2010. Stress and personalities: risk-taking behavi- aversive learning in a wild verte- our in a social and a non-social brate: The role of corticosterone situation. Behavioral Ecology, 16, in mediating escape from a no- 716-723. 54 M.W. Seltmann

Veenema, A.H., Koolhaas, J.M., & R.D. 1998. Ecological bases of de Kloet, E.R. 2004. Basal and hormone-behavior interactions: stress-induced differences in HPA The „Emergency life history sta- axis, 5-HT responsiveness, and ge“. American Zoologist, 38, hippocampal cell proliferation in 191–206. two mouse lines. Annals of the Wolf, M., van Doorn, G.S., Lei- New York Academy of Science, mar, O. & Weissing, F.J. 2007. 1018, 255–265. Life-history trade-offs favour the Waldeck, P., Kilpi, M., Öst, M. & evolution of animal personalities. Andersson, M. 2004. Brood para- Nature, 447, 581–584. sitism in a population of common Wolf, M., van Doorn, G.S. & Weis- eider (Somateria mollissima). Be- sing, F.J. 2008. Evolutionary haviour, 141, 725-739. emergence of responsive and un- Wilcoxen, T.E., Boughton, R.K., responsive personalities. Procee- Bridge, E.S., Rensel, M.A. & dings of the National Academy Schoech, S.J. 2011. Age-related of Sciences of the U.S.A., 105, differences in baseline and stress- 15825–15830. induced corticosterone in Florida Wolf, M. & Weissing, F.J. 2010. An scrub-jays. General and Compa- explanatory framework for adapti- rative Endocrinology, 173, 461– ve personality differences. Philo- 466. sophical Transactions of the Royal Wilson, D.S., Clark, A.B., Coleman, Society B, 365, 3959–3968. K. & Dearstyne, T. 1994. Shyness Wolf, M. & McNamara, J.M. 2012. and boldness in humans and other On the evolution of personalities animals. Trends in Ecology and via frequency-dependent selec- Evolution, 11, 442–446. tion. American Naturalist, 179, Wilson, D.S. 1998. Adaptive indi- 679–692. vidual differences within single Wolf, M. & Weissing, F.J. 2012: populations. Philosophical Tran- Animal personalities: consequen- sactions of the Royal Society B, ces for ecology and evolution. 353, 199–205. Trends in Ecology and Evolution. Wingfield, J.C., Vleck, C.M. & 27, 452–461. Moore, M.C. 1992. Seasonal Wolf, M., van Doorn, G.S., Leimar, changes of the adrenocortical re- O. & Weissing, F.J. 2013. The sponse to stress in birds of the evolution of animal personalities. Sonoran desert. Journal of Expe- In: Carere, C. & Maestripieri, D. rimental Zoology, 264, 419–428. (eds) Animal personalities. Be- Wingfield, J.C., Maney, D.L., Breu- havior, physiolgy, and evolution. ner, C.W., Jacobs, J.D., Lynn, S., The University of Chicago Press, Ramenofsky, M. & Richardson, Chicago. Personalities in female eiders 55

Yoccoz, N.G., Erikstad, K.E., Bust- Zanette, L.Y., White, A.F., Allen, nes, J.O., Hanssen, S.A. & Tveraa, M.C. & Clinchy, M. 2011. Per- T. 2002. Costs of reproduction in ceived predation risk reduces the common eiders (Somateria mol- number of offspring songbirds lissima): an assessment of rela- produce per year. Science, 334, tionships between reproductive 1398–1401. effort and future survival and re- Zera, A.J. & Harshman, L.G. 2001. production based on observational The physiology of life-history and experimental studies. Journal trade-offs in animals. Annual Re- of Applied Statistics, 29, 57–64. view of Ecology, Evolution, and Systematics, 32, 95–126. Martin Walter Seltmann Martin Martin W. | Seltmann Of milquetoasts and daredevils – Personalities in female eiders

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