Personality and foraging decisions in fallow deer, Dama dama

Animal Behaviour 81 (2011) 101e112

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Personality and foraging decisions in fallow deer, Dama dama Ulrika A. Bergvall a, b, *, Alexander Schäpers b, Petter Kjellander c,1, Alexander Weiss a, 2 a

Department of Psychology, School of Philosophy, Psychology and Language Sciences, University of Edinburgh Department of Zoology, Stockholm University c Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences b

a r t i c l e i n f o Article history: Received 7 June 2010 Initial acceptance 13 July 2010 Final acceptance 7 September 2010 Available online 20 October 2010 MS. number: 10-00402R Keywords: antipredator behaviour boldness Dama dama dominance fallow deer foraging novelty personality

Recent studies have examined the ecological and evolutionary bases for variation in animal personality. However, only a few such studies have examined how foraging parameters are influenced by different personality domains. In wild ungulates, the trade-off between the time spent on food intake and antipredator behaviour differs between individuals, but the underlying reason for this is not yet well understood. One possibility is that this trade-off reflects personality dimensions such as boldness. To relate foraging decisions to personality we measured personality and performed feeding experiments with familiar and novel food in familiar and novel situations. We measured personality traits in 15 tame fallow deer, using novel object tests (NO), behavioural observations (BO) and personality ratings (PR). Boldness dimensions were found using PR and NO, dominance dimensions were found using BO and PR, and a flexibility dimension was found using BO. Multitraitemultimethod analysis showed that similar dimensions were significantly correlated across different methods and that different dimensions were not significantly correlated, even if measured using the same method. We also found that novel food eaten in familiar situations and familiar food eaten in novel situations were strongly related to boldness but not dominance, flexibility or age. Thus the trade-off between the benefits of gaining more food and the costs of reduced vigilance or increased toxin ingestion reflect boldness. These findings highlight the nature of personality dimensions in ungulates and how boldness impacts foraging behaviour. Ó 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Recent studies have examined the ecological and evolutionary bases for variation in animal personality. According to balancing selection theory, frequency-dependent selection could maintain variation in trait values (Dall et al. 2004; Hurst 2009). Life history theory predicts that animal personality variation could be explained by trade-offs between current and future reproduction (Wolf et al. 2007). Different conditions such as variation in predation pressure (Réale & Festa-Bianchet 2003) or food availability in a fluctuating environment (Dingemanse et al. 2004) have been shown to maintain personality variation in mammals and birds, respectively. One way to address the question of why many animal populations show less plasticity in personality traits than expected is to examine how individuals react in trade-off situations (Dall et al.

* Correspondence: U. A. Bergvall, Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden. E-mail address: [email protected] (U.A. Bergvall). 1 P. Kjellander is at the Grimsö Wildlife Research Station, S-730 91 Riddarhyttan, Sweden. 2 A. Weiss is at the Department of Psychology, School of Philosophy, Psychology and Language Sciences, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, U.K.

2004). An important trade-off in wild ungulates is between time spent on antipredator behaviour and time spent on foraging (Illius & Fitzgibbon 1994). Antipredator behaviour serves to protect against predation on the individual, kin and offspring (Lima & Dill 1990; Spalinger & Hobbs 1992). Thus antipredator behaviour is adaptive, as, among iteroparous species, fitness is influenced by longevity (Gaillard et al. 2000; Kjellander et al. 2004; Weladji et al. 2006). On the other hand, vigilance carries costs: time spent watching for and guarding against predators leads to decreased food intake. For example, a study of free-ranging bison, Bison bison, and elk, Cervus canadensis, showed that individual differences in vigilance, as measured by scanning time, varied between 0 and 31% and were inversely related to bite rate (Fortin et al. 2004). In addition, maternal weight is a major factor influencing the prewinter weight of fallow deer fawns (Birgersson & Ekvall 1997), which, in turn, affects their winter survival (Guinness et al. 1978) and consequently fitness. Other factors influencing ungulate foraging decisions include plant defences (Rhoades 1979), learning (Provenza 1995), food density (Beauchamp 2009) and abundance of preferred foods (Bergvall & Leimar 2005). Mammalian herbivores normally take between 10 000 and 40 000 bites from vegetation each day (Milne 1991). They also tend to eat from several locations and, over the

0003-3472/$38.00 Ó 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.anbehav.2010.09.018

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short term, rather than immediately deciding either to eat large amounts or to reject the food, typically ingest small quantities of a variety of foods and sample novel foods (Freeland & Janzen 1974). Moreover, even familiar foods in familiar environments are often sampled, possibly because the nutrient content and toxicity of plants change frequently (Provenza et al. 1992). Thus, diet choice through constant sampling and evaluation of food is an important aspect of ruminant foraging, and sampling suggests the animal collects information about food (Shettleworth 1998). One factor underlying ungulate foraging decisions in the presence of possible predators or toxic foods includes personality. For example, a study of sheep, Ovis aries, found that sociality, as measured by stress responses (number of bleats) in social separation tests, was related to lower willingness to eat novel foods (Villalba et al. 2009). As reactions to social isolation can involve fear and sociability (Boissy 1995), boldness may be related to willingness to eat novel foods. This possibility is further supported by the fact that the neural pathways involved in fear are also involved in diet selection (Bechara et al. 1995). Finally, personality traits such as exploration may be related to willingness to eat novel foods (Réale et al. 2007). Boldness, sometimes referred to as low fearfulness or low reactivity, has been measured in species from several phyla (reviewed in Gosling 2001). It is sometimes associated with differences in exploration and antipredator behaviour in fish (Brown & Braithwaite 2004), foraging in geese (Kurvers et al. 2010) or dispersal in fish (Fraser et al. 2001). In dogs, Canis familiaris, boldness is a broad dimension, incorporating aspects of sociability, fearlessness and curiosity (Svartberg & Forkman 2002). Most studies of ungulates rely on single test measures of boldness (but see Lloyd et al. 2007; Fox & Millam 2010). For example, studies of wild ungulates have measured boldness via frequency of being trapped in salt baits (Réale et al. 2000; Réale & Festa-Bianchet 2003) and reaction to handling in captivity (Pollard et al. 1994; Pollard & Littlejohn 1995). Within domesticated ungulates, fearfulness has been frequently tested experimentally (reviewed in Boissy 1995; Forkman et al. 2007). For example, vigilance in cows, Bos taurus, is correlated with fearfulness in experimental situations (Welp et al. 2004). Studies of domesticated ungulates have also measured boldness via ratings on questionnaires to human handlers (Momozawa et al. 2005) and coding of behaviours observed in behavioural tests, including novel object or startle tests (reviewed in Forkman et al. 2007). Because it has been related to personality traits such as exploratory behaviour and aggressiveness (Verbeek et al. 1999; Dingemanse & de Goede 2004), dominance is another factor that may influence fallow deer foraging decisions. In ethology, dominance refers to the status of an individual who wins a dyadic contest (Barrette & Vandal 1986; Drews 1993). It is closely related to social rank, that is, the position in the group that a specific individual occupies (Drews 1993). High-ranking individuals are more likely to win dyadic interactions (reviewed in de Vries 2009). There is also evidence that dominance rank is related to fitness in ungulates as, in bison and mountain goats, Oreamnos americanus, rank is related to offspring weaning weight (Vervaecke et al. 2005) and reproduction (Côté & Festa-Bianchet 2001), respectively. On the other hand, a study of white-tailed deer, Odocoileus virginianus, failed to find a relationship between dominance and cumulative body mass loss during winter (Taillon & Côté 2006). Studies on dominance in wild and domesticated ungulates are common (Drews 1993), but little is known about how dominance is related to boldness, other personality traits and foraging. Studies of other species, including dogs (Jones & Gosling 2005), hyaenas, Crocuta crocuta (Gosling 1998), chimpanzees, Pan troglodytes (King & Figueredo 1997) and gorillas, Gorilla gorilla (Gold & Maple 1994)

have identified personality dimensions related to dominance that are distinct from dimensions related to boldness, aggressiveness or exploratory behaviour. The present study had two goals. First, because personality has not yet been measured in fallow deer, we sought to assess which dimensions describe individual differences in the behavioural consistencies of this species. A range of traits, including dominance and traits related to openness and curiosity (Gosling 2001), has been found in various species using different approaches. Traits can be correlated because they define an actual personality dimension or behavioural syndrome along which individuals differ. However, traits can also be correlated because they are measured in the same context, such as habitat (Dingemanse et al. 2010), or using the same method, such as a questionnaire (Campbell & Fiske 1959). As such, distinguishing between personality dimensions requires a mulitraitemultimethod design and analysis (Campbell & Fiske 1959). The second goal was to determine whether personality traits in tame fallow deer are related to foraging decisions, and, hence, to fitness. If personality traits such as boldness reflect a trade-off between the benefits of gaining more food and costs of reduced vigilance or toxin ingestion, we would predict that food intake should be influenced by personality dimensions in situations when food is presented in novel situations or when novel food is presented in familiar situations. To test this prediction, we investigated the relationships between personality traits in the context of food ingestion in three conditions: familiar food in a familiar context, novel food in a familiar context and familiar food in a novel context. METHODS Subjects Fifteen tame female fallow deer participated in experiments and studies that took place between 2007 and 2009. Subjects had been hand-raised as fawns since 1996 (N ¼ 5) and 2000 (N ¼ 10) and derived from a fenced fallow deer population at Stockholm University’s Research Station, Tovetorp, in south-central Sweden. Subjects were captured within 24 h of birth, and reared according to established procedures (Birgersson et al. 1998). Throughout the study, subjects had ad libitum access to silage (in winter months) and/or pasture, water, minerals and salt stones. There was no fasting prior to experiments. Ethical approval was granted by the Linkoping Board for Laboratory Animals. Settings Subjects were kept in a 4 ha enclosure with access to meadows, forest and water. Within this enclosure, a small holding area led into a 100 m2 experimental arena. The arena was surrounded by solid walls 1.4 m high to prevent deer on the outside from seeing into it. Novel Object Tests Procedures Novel object tests took place in the arena with one subject being tested at a time. Seventeen novel object tests were performed using 10 different objects. Novel objects used in these tests included a wheelbarrow, a toy horse, five small objects, a mirror, seven trays, two moving objects, a tarpaulin, a food bowl covered with a metal lid and a scarecrow (Appendix Table A1). Unless otherwise specified, novel object tests proceeded as follows. Prior to a trial, a novel object was placed 8 m away in the corner opposite the entrance of the experimental enclosure. When a test contained several objects or food bowls/trays, these were

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placed 8 m away from the entrance of the holding area, 90 cm from the outer fence, and there was a 2 m gap between adjacent objects. A trial began when the doors from the holding area into the arena were opened allowing a subject to choose whether and when it entered the arena. To enable us to measure latency to enter the arena and allow subjects to return to the experimenter in the holding area, the door between the holding area and the arena was kept open during a trial. We altered the order in which the subjects entered the arena so that all subjects participated in some trials early and some late in the day. To collect spatial and temporal measurements, an observer in the holding area used a hand-held computer (Psion revo PLUS). Behaviours in the arena were continuously filmed using a Sony DCR-VX1000E camera placed outside the arena.

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and in 2009 data were collected using an Eee PC with a custommade program BehaveObs (developed by T. Alm, Tranholmsv.3, 178 32 Ekerö, Sweden). Observations were conducted from 20 April 2008 to 28 May 2008 (300 min/subject), in October 2008 (80 min/ subject) and in February 2009 (160 min/subject). Each day was split into five periods so that we could control for possible diurnal variation. These periods were from dawn to 0800, 0800e1100, 1100e1400, 1400e1700 and 1700 hours to dusk.

Latency to leave holding area. With the exception of the open lid test, we measured the time (s) from when the door in the holding area was opened to when the subjects entered the arena.

Learning Learning trials took place in 2008 and were conducted in the experimental arena. Only one subject was trained at a time and only one exercise was taught each day. Clicker training was used to train subjects with positive reinforcement (Pearce 2008). In the present study, we first determined which food reward (pellets, oats, raisins or some combination of two of these) was preferred by individual subjects and associated the clicker with this food reward. After the clicker acquired the status of a secondary reinforcer, we used positive reinforcement to teach subjects a foot target, mouth target and free-shaping task. Measures recorded during these tasks were number of correct responses at the end of each training session, total time spent on training before the test and number of reinforcements delivered.

Approach rank. This measure ranked subjects on how close they were to the novel object and their latency to reach the object. If they did not reach the object, latency was scored as the time (s) it took to reach the zone closest to the object. Thus, the subject with the lowest latency that moved closest to the novel object received a score of 15 and the subject with the highest latency and was the furthest from the novel object received a score of 1.

Mouth target task. On the first day, subjects were taught to touch a target (a tennis ball on a stick) when it was presented to them. On the second day, subjects were taught to touch the target when it was presented in front of them and they needed to take one step to reach it. On the third day, subjects were taught to touch the target when it was presented in different places and they needed to take more than one step to reach it.

Behaviours. Video recordings of behaviours were transferred to a computer and analysed with Windows Movie Maker Version 5.1. We noted the duration and frequency of behaviours (column 5 of Appendix Table A1). Behavioural measures included the duration and frequencies of vigilance and ‘tensed state,’ defined as a combination of jerk, trot, canter, jump, spook, back-step, high legs, tail horizontal and tail erected (Vierin & Bouissou 2002; Caro et al. 2004; Lansade et al. 2008). We also noted the time subjects spent walking, how long it took subjects to start investigating the object (latency), and the time subjects spent investigating the object (investigation). The latter was defined as occurring when a subject touched the object, or was less than half a head length away from the object.

Foot target task. On day 1, subjects were taught to use their noses to touch a white plastic lid on the ground, which concealed a food reward. On day 2, subjects were taught to use their foot in the presence of the white plastic lid when it did not conceal a food reward. In this task, subjects did not have to touch the lid and were reinforced for using their leg and hoof.

Measures Proximity of the subjects to novel objects. In the novel object tests, proximity to novel objects was measured using six lines 1.2 m apart, which were drawn on the ground.

Behavioural Observations We recorded 47 different behaviours and measures in nine experiments. A summary of the behaviours in these experiments is presented in Appendix Table A2. Free-ranging behaviour Each subject was observed for 9 h while it was in the 4 ha enclosure. We collected three categories of behaviours using continuous monitoring (Altmann 1974). The first category included minutes spent on behaviours related to activity, such as grazing, lying down and moving. The second category included frequency and duration (s) of behaviours related to vigilance or self-grooming. Vigilance was defined as occurring when the subject raised its head with ears cupped and pointed forward. We noted whether vigilance occurred during grazing and whether the animal stopped chewing when performing these behaviours. The third category included frequency of specific behavioural events (e.g. being bitten by others). In 2008, data were collected using an ethogram protocol

Freeshaping. During these trials, the trainer shaped naturally occurring behaviours via reinforcement. On day 1, subjects were reinforced for moving their head to the left. On day 2, subjects were reinforced for taking two steps to the left. Rank David’s score. This measure of rank is based on outcomes of antagonistic interactions among group members and takes into account repeated interactions (Gammel et al. 2003). We calculated these scores based on all winelose dyadic competitions that occurred over 75 h of behavioural observations in April and May 2008. Dominance test. We measured dominance in 53 pairwise contests. In each contest we let two subjects enter the arena and then put a single bowl containing 200 g of pellets into the arena 8 m from the entrance. All interactions between subjects were recorded and the loser was able to leave the arena via the holding area. From these contests a rank order was constructed, and behaviours related to dominance were recorded. We did not record an order between subjects if the trial had to be cancelled or when interactions were too subtle to determine which subject was dominant. Order of encounter. We also assessed rank by the order in which subjects entered the arena in the seven learning trials. Subjects that entered the arena earlier were higher ranking than those that entered the arena later.

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Control Behavioural observations were also recorded in a control condition in which subjects were observed in the arena when there were no novel objects present. We measured the walk and lines crossed in three control experiments. Personality Ratings Three persons involved in different parts of the study and in handling the subjects independently rated each deer on a modified version of a questionnaire previously used to rate horses, Equus caballus (Fairholm 2007). The original questionnaire consisted of 58 items and was a modified version of an instrument used to rate chimpanzees (King & Figueredo 1997; Weiss et al. 2009) and orangutans, Pongo pygmaeus (Weiss et al. 2006), which, in turn, was based on measures of human personality (McCrae & Costa 1985; Goldberg 1990; Costa & McCrae 1992). Each item consisted of a personality descriptive adjective and one to three sentences which set the adjective in the context of deer behaviour (e.g. ‘DOMINANT: subject is able to displace, threaten, bite, jump on, or take food from other fallow deer. Or subject may express high status by decisively intervening in social interactions’). Ratings were made on 7-point Likert scales with ‘1’ indicating that a subject ‘Displays either total absence or negligible amounts of the trait.’ and ‘7’ indicating that a subject ‘Displays extremely large amounts of the trait’. Raters were instructed to base their ratings on the subjects’ behaviours in different situations and interactions with other fallow deer and not to discuss their ratings with others. Foraging Familiar food consisted of either the natural vegetation growing in the enclosure or a commercially available livestock forage (food pellets). The food pellets (Viltfor, manufactured by Lantmännen, Sweden) are intended for cervids and made of corn, milling byproducts, sugar beet by-products, minerals, vitamins, fat and vegetable oils (10.5 MJ digestible energy and 120 g crude protein per kg). For natural vegetation, foraging was measured as latency to graze, time spent grazing (Marchetti & Zehtindjiev 2009) and food ingestion rate (FIR; Owen-Smith 1979), which measures the proportion of total time devoted to feeding. Duration of grazing was recorded from the time when cropping started to the time when the head was lifted for at least 2 s and/or cropping stopped for at least 3 s. When the familiar food consisted of pellets, foraging was measured as food intake (g). Familiar food in familiar situations Intake of familiar food in familiar situations was measured as the FIR during the 9 h of behavioural observations during free ranging in the 4 ha enclosure, grazing or amount (g) of pellets eaten in the arena when no novel object was present. Familiar food in novel situations Consumption of familiar foods in novel situations was measured in the 17 novel object tests. In 12 tests the familiar food consisted of pellets (11 in 2007 and 1 in 2008) and in five the familiar food consisted of the naturally occurring food plants from the enclosure (2008). Novel food in familiar situations In 2007 and 2008, 25 novel foods were offered to subjects in four novel food tests (Appendix Table A3). Each test lasted 5 min and consisted of seven bowls, each containing 25 g of food. In all tests, bowls were placed 8 m away from the entrance of the holding

area and 90 cm from the outer fence; there was a 2 m gap between adjacent bowls. In the first test all of the bowls contained novel foods, whereas in tests 2, 3 and 4 one of the bowls contained familiar pellets. In all tests the subjects had not encountered the novel foods in any previous part of the study. All subjects visited all food bowls in all tests. Thus, subjects had the opportunity to sample all foods. Statistical Methods Data reduction To determine the dimensions describing subject performance in novel object tasks, observed behaviours or personality ratings, we performed three principal components analyses. This technique is used to reduce a large number of correlated variables into a smaller set of variables (Gorsuch 1983). It is especially suitable for occasions when the role of each of the correlated measures is unknown. While the subject to item ratio was small in all three analyses, research has shown that factor analyses of even very small samples can yield a stable factor pattern (Kone cná et al. 2008; de Winter et al. 2009). We chose to use principal components analysis as opposed to principal axis factor analyses because these analyses are exploratory and the structures derived using both methods are highly similar (Velicer 1977; Weiss et al. 2006). Prior to the analysis of the novel object test (NO), we examined whether measures from single tests (e.g. leave holding area) had high and significant correlations with measures from at least one other test (e.g. wheelbarrow). In all such cases, we computed the average of the measures. Otherwise the measure was used on its own (i.e. time investigating the object). This procedure yielded 17 novel object test measures for the analysis. For the principal components analysis of behavioural observations (BO) we included the measures from the learning tests, dominance tests, control tests (activity) and behavioural observations. For the principal components analysis of the personality ratings (PR), we first estimated interrater reliabilities using two types of intraclass correlation coefficients (ICCs) described by Shrout & Fleiss (1979). Both ICCs assume that the target (deer) effects are random and the rater effects are fixed. The first, ICC(3,1), indicates the reliability of individual ratings. It is derived by dividing the difference of the between-target mean square and the error mean square (BMSeEMS) by the sum of the between-target mean square and the product of the number of judges (k) minus 1 and the error term mean square [BMS þ (k  1)EMS]. The second, ICC(3,k), indicates the reliability of the mean ratings of judges. It is derived by dividing (BMSeEMS) by the between-target mean square (BMS). The interrater reliabilities of 47 of the items were greater than 0 and used in the analysis. Interrater reliabilities for these items ranged from thoughtless (ICC[3,1] ¼ 0.05; ICC[3,k] ¼ 0.14) to timid (ICC [3,1] ¼ 0.69; ICC[3,k] ¼ 0.87). We used parallel analyses to determine the number of components (Horn 1965; O’Connor 2000). This procedure involves generating eigenvalues for components from 1000 random data sets with the same number of items and subjects. If an eigenvalue of a component from the actual data exceeds the 95th percentile of eigenvalues from the random data sets, that component is retained. For the purpose of interpreting and scoring factors, we defined absolute loadings greater than or equal to 0.40 as salient. If items had salient loadings on more than one component, we assigned it to the component on which it had the higher loading. We computed component scores by transforming items into z scores and then using unit weighing. Thus, the z scores of items with positive salient loadings on a component were weighted þ1, those of items with salient negative loadings on a component were weighted 1, and those of items that did not have a salient loading

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on a component were weighted 0. We used this procedure to generate scores because it yields scores that are more generalizable across studies while still being highly correlated with differentially weighted scores (Gorsuch 1983; pp. 266e270). Finally, we assessed the extent to which the items used to compute each unit-weighted component were correlated with one another, that is, the internal consistency of scales, by computing standardized Cronbach’s (1951) alphas. Multitraitemultimethod analysis We obtained Spearman rank correlations between the personality scores based on the NO, BO and PR components. We used these correlations to identify personality dimensions that were correlated despite being measured using different methods (NO, BO or PR) and those unique to a particular type of measure. In addition, each of the three persons who rated subjects helped conduct different experiments and behavioural observations. Therefore, where possible, we tested whether personality dimensions derived via the ratings of one experimenter correlated with personality dimensions derived via behavioural measures of another experimenter. Foraging parameters We used regression analysis to examine the relationship between personality and foraging. In each regression the dependent variable was the foraging parameter (pellets, grazing or FIR) measured over both years combined. Predictor variables included age in years and personality traits. Sensitivity analysis Because of the small sample size, we performed a sensitivity analysis to determine how more stringent cutoff points for interrater reliabilities and salient loadings would influence the results. This involved running the multitraitemultimethod analyses and the regression analyses on personality and foraging parameters three times. In all three cases we defined absolute loadings of NO and BO measures greater than or equal to 0.80 as salient. In the first condition, we used the same set of PR items, but defined absolute loadings greater than or equal to 0.80 as salient. In the second condition, we used our original cutoff point for salient loadings, but conducted analyses only on PR items with ICC(3,1)s greater than or equal to 0.30. In the third condition, we used only PR items with ICC (3,1)s greater than or equal to 0.30 and defined absolute loadings greater than or equal to 0.80 as salient. RESULTS Principal Components Analysis Principal components analysis of the 17 NO measures revealed a single boldness component which explained 41.48% of the variance including proximity to novel objects, latency to leave the holding area and the frequency and duration of behaviours related to vigilance (Table 1). Of these measures, all but two had salient loadings. Principal components analysis of the 47 BO measures yielded two factors that explained 41.36% of the variance (Table 2). We rotated these components using the varimax procedure. The first component comprised behaviours related to dominance rank (e.g. rank in entering the arena, winning competitions), unilateral aggression (e.g. biting other individuals but not being bitten by others) and leadership (e.g. herding and winning agonistic interactions). This component was thus clearly related to dominance in female fallow deer. We therefore named this component ‘dominance’. Items related to the second component included those

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Table 1 Principal components analysis of measures from the 17 novel object tests performed in 2007 and 2008 Measure

Boldness

Approach rank, including closeness and time (10) Proximity to novel objects (17) Latency to leave holding area (15) Duration of vigilance (6) Frequency of vigilance (6) Tense behaviours (6) Closeness to Wheelbarrow object (2) Closeness to Scarecrow object (3) Closeness to Horse object (1) Time investigating Wheelbarrow object (2) Time investigating 5 novel objects (1) Walk (6) Crossed lines (6) Time in the field of vision in Mirror test (1) Number of objects visited in 5 novel objects test (1) Time at Scarecrow object (3) Time investigating Horse object (1) Eigenvalue Total variance %

L0.95 L0.91 0.82 0.72 0.70 0.68 L0.66 L0.64 L0.62 L0.58 L0.57 0.54 0.50 L0.50 L0.47 0.39 0.36 7.05 41.48

N ¼ 15. The number of measures out of a total of 87 is in parentheses. Boldface indicates component loadings equal to or greater than 0.40.

demonstrating better performance on the learning tasks (e.g. freeshaping trials). This component also loaded negatively on behaviours related to submissiveness (e.g. observed submissive behaviours) and agonistic encounters (e.g. being bitten and chased). This pattern of loadings suggests that, independent of dominance, animals high in this dimension were better at learning and better at avoiding bites and other aversive stimuli. As such, we named this component ‘flexibility’. The principal components analysis of the personality ratings yielded two components that accounted for 69.77% of the variance (Table 3). The first component was broad and loaded on items related to human personality dimensions (McCrae & Costa 1985; Goldberg 1990; Costa & McCrae 1992) such as neuroticism or emotional stability (e.g. fearful and stable), conscientiousness or internal controls (e.g. disorganized, persistent), and openness or curiosity (e.g. curious about deer or objects). This pattern of loadings makes it fairly consistent with definitions of boldness in other species (Svartberg & Forkman 2002; Brown & Braithwaite 2004; Momozawa et al. 2005; Wilson & Stevens 2005) and we thus named it ‘boldness’. The second component derived from ratings comprised items related to dominance and rank order (e.g. dominant, submissive), but also included items related to aggression (e.g. aggressive, bullying and stingy/greedy) and activity (active, lazy). Among humans, these items are primarily related to low agreeableness, although some are also related to higher extraversion (McCrae & Costa 1985; Goldberg 1990). We thus named this component ‘dominance’. MultitraiteMultimethod Analysis The correlations in the lower diagonal of Table 4 are indicative of convergent and discriminant validity: the same personality dimensions assessed via different methods (e.g. dominance assessed via PR and dominance assessed via BO) were correlated more highly than component scores of different dimensions assessed via the same method (e.g. dominance and boldness assessed via PR). The values in the upper diagonal indicate that the relationships between PR dominance and boldness and their BO and NO counterparts held when they were assessed by different individuals.

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Table 2 Varimax rotated component loadings from 47 measures taken during behavioural observations from 2007 to 2009 Measure

Dominance

DC Total aggressive behaviour Order of entering arena (7) DC Bite OBS Dominant behaviour OBS Groom other individual DC Dominance rank from contest DC Chase OBS Win OBS Vigilance: spare time duration OBS Herding David’s score calculated from winelose OBS Group size DC Bitten OBS Vigilance: spare time frequency OBS Vigilance: stop grazing duration OBS Vigilance: stop grazing frequency OBS Vocalize OBS Biting OBS Being groomed by other DC Chased DC Submissive OBS Vigilance: grazing chew duration OBS Push head against other individual OBS Walk RT Free-shaping trials (2) RT Free-shaping time (2) RT Free-shaping success (2) OBS Bitten OBS Trot OBS Lose OBS Submissive OBS Herded by other Walk in control situations (3) OBS Nosed by other OBS Nose on other OBS Vigilance: grazing chew frequency RT Target stick and foot, success (5) OBS Agitate Lines crossed in control situations (3) OBS Gallop OBS Self-groom duration RT Target stick and foot, trials (5) Stranger test (3) OBS Self-groom frequency OBS Distance to other individuals DC Fight standing on hindlegs RT Target stick and foot, time (5) Eigenvalue Total variance %

0.91 0.90 0.85 0.84 0.82 0.79 0.74 0.73 0.72 0.68 0.65 L0.62 L0.61 0.59 0.57 0.57 0.57 0.57 0.50 L0.49 L0.49 L0.47 0.41 L0.40 0.05 0.01 0.28 0.17 0.19 0.24 0.11 0.25 0.18 0.09 0.24 0.33 0.17 0.11 0.22 0.17 0.01 0.24 0.05 0.05 0.23 0.08 0.01 11.31 24.07

Flexibility 0.11 0.13 0.31 0.35 0.06 0.19 0.43 0.45 0.18 0.29 0.36 0.58 0.04 0.12 0.23 0.40 0.52 0.05 0.43 0.22 0.29 0.07 0.02 0.39 L0.91 L0.87 L0.85 0.80 0.77 0.73 0.64 0.59 0.48 0.44 0.36 0.04 0.33 0.32 0.28 0.28 0.25 0.20 0.19 0.18 0.09 0.08 0.04 8.13 17.29

N ¼ 15. The number of measures out of a total of 47 is in parentheses after the measure, if any; otherwise it is a single measure. Boldface indicates the highest component loading greater than or equal to 0.40. OBS: during behavioural observations when deer were free ranging; DC: during dominance contest; RT: during reinforcement training.

Table 3 Intraclass correlation coefficients (ICC) and varimax rotated component loadings from 47 reliable ratings from personality ratings Item

ICC(3,1)

ICC(3,k)

Boldness

Dominance

Cautious Fear Stable Quitting Timid nonsocial Excitable Anxious Decisive Innovative Inventive Disorganized Persistent Timid social Curious about deer Distractible Vulnerable Cool Defiant Playful Unemotional Intelligent Aggressive Friendly to fallow deer Bullying Irritable Jealous Gentle towards fallow deer Manipulative Stingy/greedy Sympathetic Active Submissive Dominant Erratic Inquisitive Dependent/follower Friendly to humans Lazy Independent Gentle towards humans Helpful Curious about objects Impulsive Conventional Individualistic Thoughtless Predictable Eigenvalue % Total variance

0.54 0.60 0.12 0.31 0.69 0.41 0.45 0.30 0.49 0.56 0.17 0.14 0.55 0.39 0.24 0.13 0.15 0.06 0.09 0.49 0.37 0.63 0.34 0.42 0.23 0.20 0.28 0.17 0.43 0.20 0.23 0.44 0.43 0.06 0.16 0.07 0.26 0.29 0.50 0.59 0.42 0.31 0.16 0.24 0.63 0.05 0.14

0.78 0.82 0.29 0.58 0.87 0.67 0.71 0.56 0.75 0.79 0.38 0.33 0.78 0.66 0.48 0.32 0.35 0.15 0.22 0.74 0.64 0.83 0.60 0.68 0.47 0.43 0.54 0.38 0.69 0.43 0.47 0.70 0.69 0.17 0.37 0.17 0.51 0.55 0.75 0.81 0.68 0.57 0.37 0.49 0.83 0.14 0.33

L0.94 L0.92 0.92 L0.90 L0.87 L0.86 L0.85 0.84 0.83 0.83 L0.82 0.78 L0.75 0.75 L0.73 L0.65 0.65 0.62 0.61 0.58 0.51 0.38 0.31 0.38 0.25 0.39 0.41 0.35 0.41 0.20 0.55 0.45 0.44 0.27 0.48 0.40 0.29 0.18 0.66 0.31 0.07 0.58 0.41 0.44 0.32 0.26 0.06 23.88 50.81

0.23 0.19 0.01 0.14 0.37 0.39 0.11 0.27 0.40 0.21 0.09 0.24 0.55 0.44 0.38 0.33 0.13 0.27 0.48 0.56 0.10 0.88 L0.87 0.86 0.86 0.84 L0.80 0.79 0.77 L0.77 0.76 L0.76 0.75 0.75 0.72 L0.72 L0.71 L0.70 0.68 L0.67 L0.67 0.64 0.64 L0.64 0.61 L0.58 L0.51 8.91 18.96

N ¼ 15. Boldface indicates the highest component loading equal to or greater than 0.40.

Foraging Parameters For these analyses the personality variables dominance, boldness, and flexibility were based on the average of the z scores for PR and BO dominance, the average of the z scores for NO and PR boldness, and the z score for BO flexibility. Familiar food in familiar situations The regression analyses to examine whether the personality dimensions were related to intake of familiar foods in familiar situations revealed that personality had no impact on food intake (Fig. 1). However, grazing in familiar situations (time spent grazing and latency to start grazing) but not FIR was related to flexibility (Table 5). Age did not influence intake of familiar foods in familiar situations (Table 5). Finally, in experimental tests involving familiar foods in familiar situations all deer consumed all pellets.

Table 4 Intercorrelations between factor scores calculated by unit weighting of scores from personality ratings (PR), behavioural observations (BO) and novel object (NO) tests on the bottom diagonal PR

BO Boldness

Dominance Boldness

(0.96) 0.43

(0.96)

BO

Dominance Flexibility

0.70 0.16

0.41 0.21

(0.90) 0.30

(0.88)

NO

Boldness

0.15

0.79

0.24

0.01

PR

Dominance

NO

Dominance

Flexibility

Boldness

0.57 0.70

(0.94)

On the top diagonal are single raters’ correlations with measures from experiments in which they did not participate. Boldface indicates significant correlations (P < 0.05) from Spearman rank correlation tests. The diagonal shows standardized Cronbach’s alpha.

U.A. Bergvall et al. / Animal Behaviour 81 (2011) 101e112

3

Food intake z - score

Table 6 Familiar food in novel situations

Novel foods in Familiar situations Familiar foods in Novel situations Familiar foods in Familiar situations

2

107

Grazing

b

Pellets 95% CI

t10

b

P

95% CI

t10

P

Boldness 0.70 0.27, 1.13 3.17 0.01 0.77 0.36, 1.19 3.66 0.004 Dominance 0.10 0.33, 0.53 0.46 0.65 0.13 0.54, 0.28 0.61 0.56 Flexibility 0.25 0.75, 0.24 1.00 0.34 0.46 0.02, 0.94 1.89 0.09 Age 0.41 0.91, 0.09 1.62 0.14 0.00 0.48, 0.48 0.01 0.99

1

0

Regression values are shown for grazing in the experimental enclosure (latency and time) and consumption of pellets during novel situations. CI: confidence interval.

−1

boldness, dominance and flexibility in female fallow deer. Even when different persons rated subjects and conducted the behavioural measures, boldness and dominance as assessed by personality ratings were strongly related to novel object test measures and behavioural observations, respectively. Moreover, the personality ratings suggested that boldness was a broad and complex dimension in deer. Items loading on this factor have been identified in humans, chimpanzees and orang-utans as reflecting high emotional stability and conscientiousness as well as aspects of high sociability and curiosity (McCrae & Costa 1985; Goldberg 1990; King & Figueredo 1997; Weiss et al. 2006). Studies of some species have shown a correlation between boldness and aggression (Johnson & Sih 2005). The behavioural observations and personality ratings suggested that aggression was one aspect of dominance in deer. In addition, the personality ratings suggested that other aspects of dominance in deer included lower altruism, emotional stability and behavioural conformity as well as higher exploratory tendencies (McCrae & Costa 1985; Goldberg 1990; King & Figueredo 1997; Weiss et al. 2006). Finally, we found that boldness, but not dominance or flexibility, was consistently related to greater amounts of food eaten when either the food or situation was novel. However, boldness was not related to how many different types of food the subjects ate, but the deer in the present study visited all novel food bowls and therefore probably smelled all of the novel food items, which could have been the cue used to decide whether or not to eat the food. We also found that flexibility was related to grazing of familiar foods in familiar situations, although the sensitivity analysis indicated that this result was not robust. The personality ratings demonstrate that boldness is a broad and complex dimension in the sense that it is described not only by behaviours related to boldness and exploration, but also by traits such as persistent, intelligent and playful. These findings are consistent with work by Svartberg & Forkman (2002) who found that, among dogs, a broad higher-order boldnesseshyness factor explains playfulness, chase-proneness, sociability and curiosity/ fearlessness, but not aggression. The present findings are also consistent with earlier work, which has linked boldness to a variety of behaviours, including foraging and exploration (Wilson & Stevens 2005), antipredator behaviour (Brown & Braithwaite 2004) and general activity (Wilson & McLaughlin 2007). The complex nature of dominance is also not unique to this study. Consistent with the ethological literature (e.g. de Waal 2000) showing that rising in the ranks of chimpanzee society requires

−2 −2.0

−1.5

−1

−0.5

0 0.5 Boldness z - score

1

1.5

2

Figure 1. Boldness scores in relation to intake of novel food in familiar situations, intake of familiar food in novel situations and intake of familiar food in familiar situations (N ¼ 15). Figure by the authors, licensed under the Creative Commons Attribution 3.0 Unported License and published under the terms of the Creative Commons 3.0 Unported License.

Familiar food in novel situations Regression analyses indicated that higher boldness was significantly related to greater consumption of pellets during novel object tests (Fig.1, Table 6). In addition, boldness but not dominance, flexibility or age was related to more grazing during novel object tests (Table 6). Novel food in familiar situations All subjects consumed all food pellets in the trials that took place in 2008 and all of the wheat presented in the test that took place in 2007, indicating that the deer were motivated to eat. All food bowls were visited at least once, suggesting that subjects had the opportunity to test all foods. Hence, some information about the foods could have been derived by smelling the foods. Higher boldness was positively related to the amount of novel food consumed (Fig. 1, Table 7). Dominance, flexibility and age were not related to the amount of novel food consumed. In addition, the number of food types tested was not related to any of the personality dimensions or age (Table 7). Sensitivity Analysis Increasing the cutoff point for the interrater reliabilities or loadings that were considered salient did not substantially influence the results (Appendix Tables A4eA13). The only difference was that the relationship between the flexibility dimension and one of the measures related to foraging from familiar foods in familiar situations (grazing in the arena with no novel objects present) was no longer significant (Appendix Table A5). DISCUSSION Using novel object tests, behavioural observations and personality ratings, we identified distinct personality dimensions labelled Table 5 Familiar foods in familiar situations

Table 7 Novel food in familiar situations

Grazing

b

95% CI

FIR t10

P

b

Boldness 0.30 0.23, 0.83 1.11 0.29 0.23 Dominance 0.30 0.83, 0.22 1.12 0.29 0.04 Flexibility 0.77 0.16, 1.38 2.46 0.03 0.49 Age 0.53 0.08, 1.15 1.71 0.12 0.31

Amount (g) 95% CI 0.40, 0.58, 1.21, 1.03,

t10

P

0.85 0.71 0.49 0.66 0.13 0.90 0.23 1.34 0.21 0.41 0.84 0.42

Regression values are shown for grazing in the experimental enclosure (latency and time) and food ingestion rate (FIR) during free ranging. CI: confidence interval.

b

95% CI

Types t10

P

b

Boldness 0.63 0.10, 1.16 2.32 0.04 0.34 Dominance 0.10 0.63, 0.42 0.38 0.71 0.10 Flexibility 0.41 0.20, 1.03 1.32 0.22 0.29 Age 0.10 0.51, 0.72 0.33 0.75 0.19

95% CI 0.29, 0.52, 0.44, 0.54,

0.97 0.73 1.01 0.91

t10

P

1.06 0.33 0.78 0.50

0.32 0.75 0.46 0.63

Regression values are shown for the amount (g) and number of types of novel food consumed. CI: confidence interval.

108

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more behavioural resources than aggression and swagger, a questionnaire-based study of chimpanzees’ personality revealed that dominance comprised many seemingly disparate traits (King & Figueredo 1997). Thus, the present findings suggest that rank in female deer may also be linked by a combination of multiple physical (Holand et al. 2004) and psychological characteristics (Côté 2000). Flexibility in this study was only identified in BO (behavioural observations). Similar behaviourally based personality dimensions have not previously been identified in ungulates. However, a potentially related trait (Trainability) has been identified in horses; this was related to ‘Concentration’, ‘Memory’ and ‘Perseverance’, but not to ‘Anxiety’ (Momozawa et al. 2005). Moreover, in pigs, Sus scrofa, individuals classified as high-resisting in a Back test (i.e. restraint test) were also more prone to reverse learning, indicating that a behavioural trait dimension related to flexibility is also present in this species (Bolhuis et al. 2004). Thus, further investigations may explore the presence of traits related to behavioural flexibility and the possible evolutionary mechanisms for the maintenance of such traits in the population. While we did not find a relationship between flexibility and food intake, it is worth speculating about what trade-off may maintain variation in flexibility. If individuals low in flexibility avoid dominant individuals less, they might also be more likely to climb in rank. On the other hand, they might be more reluctant to risk injury during such situations. If flexibility is related also to the ability to adjust to certain situations, individuals high in flexibility might be able to learn more from the consequences of their own behaviour. Our findings regarding boldness and food intake are consistent with other studies, including one on barnacle geese, Branta leucopsis, which showed that bolder individuals ate more (Kurvers et al. 2010), and studies of domesticated ungulates showing that weight gain was negatively and positively correlated with fear reactions (Fordyce & Goddard 1984) and calmness (Voisinet et al. 1997), respectively. Moreover, our finding that boldness was related to food intake only in novel situations or where the food was novel is in line with the notion that variation in boldness reflects trade-offs between offspring investment and life span (Réale et al. 2007). Bold individuals might therefore reap fitness benefits by exploiting more food resources, thus enabling them to invest more in the raising of offspring at the expense of a shorter life as a result of poisoning or being killed in accidents or by a predator while searching for food in new and unfamiliar habitats (Lima & Dill 1990; Sansom et al. 2009). In addition, since vigilance in threatening situations in our study was related to boldness, the offspring of these bold individuals will also be at greater risk from predators and other threats (White & Berger 2001; Childress & Lung 2003; Bongi et al. 2008). Changes in resource availability affect most vertebrate life history traits (Fowler 1983; Stearns 1992). Body mass and body size are affected by food availability (Ulijaszek et al. 1998), and are usually good proxies for individual performance (Clutton-Brock 1991). As a general rule the heaviest individuals survive better at all ages (Gaillard et al. 2000) and these individuals also produce more offspring over their life span than lighter individuals (Hewison 1996) in predator-free environments. Having said that, a single personality trait (fear of humans) explains between 19 and 50% of the variance in milk production in dairy cows (Breuer et al. 2000), indicating the importance of psychological traits for a trait clearly related to fitness. Given our own findings and those of others, we predict that bold females will raise heavier fawns that are less likely to suffer from starvation, but that such females, and their fawns, will be more prone to predation. At the same time, we predict that shy females and their offspring will be less prone to predation, even though the fawns will be lighter and at greater risk of starvation. Accordingly, selection pressures on boldness should be dependent on both environmental variation, such as winter severity or summer droughts, and predator

density. Thus, the different personality types will have different fitness optima and coexist in the population. Future studies investigating female vigilance and fawn survival in low- and high-predation areas will be useful to investigate this possible trade-off further. Moreover, investigating female postfawning behaviour and fawn survival could indicate the extent to which females alter their vigilance and explore their home range during this period. Based on personality theory, we expect that females showing the highest increases in vigilance should also have the most conservative home range use during fawning and vice versa, given that personality influences antipredator behaviour during fawning, so that some females are more prone to protect their fawns, while others invest more in fawn growth, with an increased risk of fawn mortality. In previous experimental studies on personality and novel foods, voluntary intake of three types of novel food was measured (Villalba et al. 2009). In our study, we measured the amount of food intake and the number of foods tested and only intake of novel food was related to boldness. Neophobic reactions to food in fallow deer are probably associated with olfactory cues and are therefore processed in the limbic system (Garcia 1989). However, to associate smell with postingestive consequences requires that food be ingested. Postingestive learning is an important mechanism for diet choice in generalist herbivores (Provenza & Balph 1987), and has also been found in fallow deer (Bergvall 2009). Among wild ungulates, willingness to eat new foods may be adaptive in fluctuating environments as new food sources can be utilized more quickly. While acute poisoning is a more frequently reported phenomenon (reviewed in Nichol 1938; Fowler 1983), subacute poisoning may have less obvious effects, including growth inhibition, interference with reproduction, shortened life span, weight loss or fur loss (reviewed in Freeland & Janzen 1974; Fowler 1983), all of which can negatively affect fitness. Four classes of behaviours are related to fitness: foraging, escaping predation, reproduction and social interactions (Dukas 1998). To understand how personality variation is maintained in a population, we need to understand the make-up of all these traits, and how these traits influence fitness. Searle et al.’s (2008) ‘landscape of fear’ concept explains how foraging is a trade-off between habitats of different qualities and different levels of safety. Hawkes (2009) emphasized the importance of understanding individual specialization to explain habitat exploitation and population processes. In vertebrates, and in particular in iteroparous species, most variation in individual fitness is accounted for by variation in life span (Gaillard et al. 2000) and offspring survival (Clutton-Brock et al. 1988). Our study shows how behaviours related to fitness are influenced by personality, and, in turn, shed some light on how personality differences can be maintained in the population. Acknowledgments We thank Pernilla Wahlqvist for assistance with experiments in 2007, Maria Karlsson for clicker training and behavioural observations in 2008, Lisa Svensson for behavioural observations in 2009, the personnel at Tovetorp research station and Torbjörn Alm for developing a computer program used for behavioural observations. This work was supported by The Swedish Research Council to U.B. and by the Swedish Environmental Protection Agency (Wildlife management fund) to U.B. and P.K. References Altmann, J. 1974. Observational study of behavior: sampling methods. Behaviour, 49, 227e267. Barrette, C. & Vandal, D. 1986. Social rank, dominance, antler size, and access to food in snow-bound wild woodland caribou. Behaviour, 97, 118e146. Beauchamp, G. 2009. How does food density influence vigilance in birds and mammals? Animal Behaviour, 78, 223e231.

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APPENDIX

Table A1 Measures and set-ups for novel object tests Test

Year

Objects and set-up

Trials

Behavioural measures

Wheelbarrow

2008

Wheelbarrow 754026 cm, which was turned upside down in trial 2 and placed in the opposite corner

2

Horse

2008

Brown toy horse (57 cm high) placed in the opposite corner

1

Five objects

2008

1

Mirror

2008

Novel trays

2007

Moving object 1e2

2007

Moving object 3

2008

Tarpaulin

2007

Five objects (a white plastic ball with blue hexagons, a green flip-flop shoe, a white box with black letters, a tiger plush-toy 21.5 cm high, a yellow flowerpot with small paintings on its side) were placed along the arena’s outer fence Mirror (61 cm high and 50.5 cm wide), attached to fence in opposite corner from the entrance of arena with reflecting surface angled towards the left. A bowl of pellets was placed in front of the mirror, but no individual ate Seven trays of different colour, shape and size: the usual clay food bowl (to make sure that the deer had a basic interest in eating), a small blue tray, a glass bowl on a green blanket, a yellow tray, three raised trays, turquoise, white or green (24, 40 and 55 cm, respectively), to prevent subjects from seeing while feeding Same as in novel trays test above. A cotton sack (about 60 cm diameter) was attached to a cord outside the arena 2 m from the fence. The sack was moved 2 m 1 min after the trial began Five food bowls were placed in the arena. A blue convex plastic barrel (length: 52 cm; diameter: 32 cm) was attached to a cord positioned on the left side inside the arena. The cord moved the barrel approximately 1 m in the direction of the outer fence, once every minute for 4 min A green plastic tarpaulin placed in the opposite corner and seven food bowls placed in the arena. Bowls 4 and 5 (from left) were on the tarpaulin. Deer could reach bowl 5 but not bowl 4 without walking on tarpaulin

Tense state, vigilance, investigating object, approach rank Tense state, vigilance, investigating object, approach rank Tense state, vigilance, number of objects visited and time investigating objects Tense state, vigilance, time spent in field of vision (s)

Time (min)

Food measures (bowls/g)

5

Grazing

5

Grazing

5

Grazing

15

Grazing

2

5

Pellets 7/25

2

5

Pellets 5/25

1

1

Tense state, vigilance

5

Pellets 5/50

2

The total score for closeness was calculated as the time to reach bowl 4

5

Pellets 7/50

Table A1 (continued ) Test

Year

Objects and set-up

Trials

Open lid

2007

2

Scarecrow

2007

Beige clay bowl with a brown metal lid, which the subject had to move to get to the food. The task was designed so that when the lid fell back into place after attempts to open it, it made a sharp noise Straw scarecrow in blue overalls placed in the opposite corner. Subjects took part in one trial per day and trials were not conducted on consecutive days

3

Behavioural measures

Time (min)

Closeness to object, investigating object, approach rank

Food measures (bowls/g)

5

Pellets 1/100

5

Pellets 1/50

All experiments were performed in the experimental arena. Basic measures are latency to leave vestibule (except for Open lid) and proximity of the subjects to novel objects. Additional measures are explained in the table. Table A2 Measures and set-ups for behavioural observations Experiment

Test

Year

Trials

Set-up

Time

Food measures (bowls/g)

2008 and 21 During free ranging in the 4 ha enclosure 2009 2008 During behavioural observations 2008 6 or 7 In experimental arena. A food bowl was placed in the opposite corner Order of encounter 2008 7 During reinforcement tests

9 h/individual

Food ingestion rate

Mouth target task Foot target task Free-shaping task Novel person

d d d 5 min

d d d d

5 min

Grazing

Free-ranging behaviour (OBS) Dominance contest David’s score (DC) Dominance test

Reinforcement tests (RT) Stranger test Control tests

2008 2008 2008 2008

3 2 2 3

2008

3

75 h observation d Until one wins or d maximum of 5 min d d

In experimental arena. Object was a tennis ball on a stick In experimental arena. Object was a white plastic lid In experimental arena. Subject was taught to take a step left In experimental arena. A person (1 male/2 females) was standing in the opposite corner In experimental arena

Table A3 Novel foods Bowl

1 2 3 4 5 6 7

Novel food test 1 (2007)

2 (2008)

3 (2008)

4 (2008)

Dry wheat Mushroom Grapes Spaghetti Sweet candy Tulips Peanuts

Chinese cabbage Cucumber Green asparagus Kidney beans Pellets Pineapple Boiled potatoes

Bamboo culms Red pepper Onion Fresh coriander Tomato Pellets Banana

Spinach Pansy Leek Pellets Raspberry Cantaloupe Carrot

Numbers represent placement of the bowl (leftmost ¼ 1, centre ¼ 4, rightmost ¼ 7).

Table A5 Regression of grazing in the experimental enclosure (latency and time) and food ingestion rate (FIR) during free ranging on personality and age Grazing

b

FIR

95% CI

t10

b

P

95% CI

Boldness 0.45 0.15, 0.74 1.46 0.17 0.01 Dominance 0.28 0.57, 0.00 0.95 0.36 0.16 Flexibility 0.71 0.33, 1.09 1.81 0.10 0.68 Age 0.53 0.16, 0.90 1.39 0.20 0.47

0.32, 0.14, 1.08, 0.85,

t10

P

0.29 0.05 0.96 0.46 0.51 0.62 0.29 1.65 0.13 0.08 1.16 0.27

Component scores based on loadings > j0.80j. CI: confidence interval.

Table A4 Sensitivity analysis for intercorrelations between NO, PR and BO component scores Measure 1

Measure 2

rS

Loadingsj0.80j BO dominance BO dominance BO flexibility PR boldness PR boldness PR boldness PR dominance PR dominance PR dominance

BO flexibility NO boldness NO boldness BO dominance BO flexibility NO boldness BO dominance BO flexibility NO boldness

0.38 0.17 0.24 0.42 0.32 0.81 0.87 0.20 0.27

ICC(3,1)0.30 PR boldness PR boldness PR boldness PR dominance PR dominance PR dominance

BO dominance BO flexibility NO boldness BO dominance BO flexibility NO boldness

0.44 0.41 0.85 0.77 0.03 0.43

Loadingsj0.80j and ICC(3,1)0.30 PR boldness PR boldness PR boldness PR dominance PR dominance PR dominance

BO dominance BO flexibility NO boldness BO dominance BO flexibility NO boldness

0.41 0.35 0.82 0.86 0.16 0.24

NO: novel object tests; BO: behavioural observations; PR: personality ratings; ICC: intraclass correlation coefficients. Spearman rank correlations (rS) in boldface are significant at P < 0.05.

Table A6 Regression of grazing in the experimental enclosure (latency and time) and consumption of pellets during novel situations on personality and age Grazing

b

Pellets

95% CI

t10

b

P

95% CI

t10

P

Boldness 0.61 0.40, 0.82 2.75 0.02 0.89 0.70, 1.09 4.39 0.001 Dominance 0.09 0.11, 0.30 0.43 0.67 0.15 0.34, 0.04 0.75 0.47 Flexibility 0.47 0.74, 0.20 1.64 0.13 0.52 0.27, 0.78 2.00 0.07 Age 0.58 0.84, 0.31 2.07 0.06 0.07 0.18, 0.31 0.26 0.80 Component scores based on loadings > j0.80j. CI: confidence interval.

Table A7 Regressions of amount (g) novel food and types of food on personality and age Amount (g)

b

95% CI

Types t10

P

b

95% CI

t10

Boldness 0.73 0.46, 1.00 2.58 0.03 0.41 0.09, 0.74 1.23 Dominance 0.18 0.44, 0.08 0.66 0.52 0.03 0.29, 0.34 0.08 Flexibility 0.44 0.10, 0.79 1.22 0.25 0.32 0.09, 0.74 0.75 Age 0.15 0.19, 0.49 0.43 0.68 0.24 0.17, 0.64 0.56 Component scores based on loadings > j0.80j. CI: confidence interval.

P 0.25 0.94 0.47 0.59

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U.A. Bergvall et al. / Animal Behaviour 81 (2011) 101e112

Table A8 Regressions of grazing in the experimental enclosure (latency and time) and food ingestion rate (FIR) during free ranging on personality and age Grazing

b

FIR

95% CI

t10

b

P

Grazing 95% CI

Boldness 0.44 0.12, 0.76 1.31 0.22 0.01 Dominance 0.32 0.62, 0.02 1.01 0.34 0.13 Flexibility 0.77 0.37, 1.16 1.87 0.09 0.69 Age 0.54 0.16, 0.91 1.38 0.20 0.47

Table A11 Regressions of grazing in the experimental enclosure (latency and time) and food ingestion rate (FIR) during free ranging on personality and age

0.32, 0.19, 1.10, 0.86,

t10

P

0.34 0.03 0.98 0.44 0.39 0.71 0.28 1.63 0.13 0.08 1.16 0.27

b

FIR

95% CI

t10

b

P

95% CI

Boldness 0.37 0.07, 0.68 1.16 0.27 0.03 Dominance 0.19 0.48, 0.11 0.61 0.56 0.18 Flexibility 0.73 0.33, 1.12 1.76 0.11 0.69 Age 0.54 0.16, 0.93 1.37 0.20 0.47

0.34, 0.12, 1.09, 0.86,

t10

P

0.28 0.10 0.92 0.48 0.57 0.58 0.29 1.67 0.13 0.09 1.18 0.27

Component scores based on loadings ICC(3,1)  0.30 for the personality ratings and loadings  j0.80j for the behavioural observations and novel object tests. CI: confidence interval.

Component scores from the personality ratings based on loadings  j0.80j and ICC (3,1)  0.30 and loadings  j0.80j for the behavioural observations and novel objects tests. ICC: intraclass correlation coefficients. CI: confidence interval.

Table A9 Regression for grazing in the experimental enclosure (latency and time) and consumption of pellets during novel situations on personality and age

Table A12 Regression for grazing in the experimental enclosure (latency and time) and consumption of pellets during novel situations on personality and age

Grazing

b

Pellets

95% CI

t10

b

P

Grazing 95% CI

t10

b

P

Pellets

95% CI

t10

b

P

95% CI

t10

P

Boldness 0.58 0.34, 0.82 2.33 0.04 0.92 0.70, 1.13 4.09 0.002 Dominance 0.11 0.11, 0.34 0.49 0.64 0.14 0.34, 0.06 0.66 0.52 Flexibility 0.44 0.73, 0.15 1.45 0.18 0.62 0.35, 0.88 2.25 0.05 Age 0.58 0.86, 0.31 2.02 0.07 0.07 0.18, 0.32 0.27 0.79

Boldness 0.59 0.38, 0.80 2.65 0.02 0.89 0.69, 1.09 4.29 0.002 Dominance 0.14 0.07, 0.34 0.65 0.53 0.13 0.32, 0.06 0.65 0.53 Flexibility 0.45 0.72, 0.17 1.57 0.15 0.57 0.31, 0.82 2.12 0.06 Age 0.57 0.83, 0.30 2.07 0.07 0.09 0.16, 0.33 0.33 0.75

Component scores based on loadings ICC(3,1)  0.30 for the personality ratings and loadings  j0.80j for the behavioural observations and novel object tests. ICC: intraclass correlation coefficients. CI: confidence interval.

Component scores from the personality ratings based on loadings  j0.80j and ICC (3,1)  0.30 and loadings  j0.80j for the behavioural observations and novel objects tests. ICC: intraclass correlation coefficients. CI: confidence interval.

Table A10 Regressions of amount (g) and types of novel food on personality and age

Table A13 Regressions of amount (g) and types of novel food on personality and age

Amount (g)

b

95% CI

Sorts t10

P

b

Amount (g) 95% CI

t10

Boldness 0.72 0.42, 1.01 2.31 0.04 0.37 0.03, 0.72 1.03 Dominance 0.12 0.40, 0.16 0.42 0.68 0.10 0.23, 0.42 0.29 Flexibility 0.52 0.15, 0.88 1.37 0.20 0.35 0.08, 0.77 0.78 Age 0.16 0.19, 0.50 0.43 0.67 0.23 0.17, 0.64 0.56

P 0.33 0.78 0.45 0.59

Component scores based on loadings ICC(3,1)  0.30 for the personality ratings and loadings  j0.80j for the behavioural observations and novel object tests. ICC: intraclass correlation coefficients. CI: confidence interval.

b

95% CI

Types t10

P

b

95% CI

t10

Boldness 0.73 0.46, 1.00 2.57 0.03 0.41 0.08, 0.73 1.20 Dominance 0.15 0.41, 0.11 0.54 0.60 0.06 0.25, 0.38 0.20 Flexibility 0.49 0.14, 0.84 1.33 0.21 0.34 0.08, 0.76 0.79 Age 0.17 0.17, 0.51 0.49 0.64 0.24 0.16, 0.65 0.58

P 0.26 0.85 0.45 0.57

Component scores from the personality ratings based on loadings  j0.80j and ICC (3,1)  0.30 and loadings  j0.80j for the behavioural observations and novel objects tests. ICC: intraclass correlation coefficients. CI: confidence interval.