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Third-party interventions of dyadic contests are often explained by appealing to high-level cognitive processes such as coalition formation between group members. However, alternative accounts that do not appeal to sophisticated cognitive processes have been proposed. We tested predictions from two such models using the fallow deer, Dama dama, as the model taxon: (1) a random target model that argues that intervention is directed randomly towards a target and (2) a specific target model that assumes that targeting is directed at contestants that have low resource-holding potential. Contrary to predictions of the specific target model, we found no evidence that targeting following third-party intervention increased as the resource-holding potential of the target declined. Both models argue that intervention serves to prevent individuals from gaining a winner effect and advancing up the hierarchy. Being targeted did not result in a decline in dominance rank, although targeting was associated with investment in dominance-related fighting tactics. Fight intervention was associated with an increase in rank early in the rut and accounted for increased mating success. Therefore, interveners benefited beyond simply preventing rivals from advancing in the hierarchy. In theoretical terms, a random target as opposed to a specific target model explains intervention behaviour in the fallow deer. [Copyright &y& Elsevier]

According to life history theory, males of iteroparous species are expected to trade off investment between current and future reproduction based on age (mating strategy or terminal investment hypotheses) or body condition (individual quality hypothesis). However, although central to this latter model, the question concerning whether and to what extent condition regulates competitive investment in polygynous species is unknown. Consequently, we investigated this issue with reference to fight structure in fallow deer contests. Support for the individual quality hypothesis was limited: males with larger necks as determined by prerut neck girth fought for longer than males with smaller necks. However, prime-aged males had higher investment in fighting than preprime- or postprime-aged males indicating that investment in fighting might be age related. Other aspects of our results also failed to support condition-related predictions; although we found that jump clashing and vocal rate were related to weight loss and decline in neck girth, respectively, there was no relationship between investment in fighting and prerut measures of body size. Moreover, we also found that rank was predicted by investment in fighting (backward pushing) rather than body condition. Our results show that, in addition to body condition and age, variation in competitive investment between individuals also influences reproductive effort in the fallow deer. [Copyright &y& Elsevier]

In general, avian species produce clutches of more than one egg. Differential investment in egg weight and hormone levels is possible and their effects on development and behaviour can be measured. Here we investigated changes in three hormones (testosterone, T; androstenedione, A4 and progesterone, P4) in the outer layer of yolks of infertile domestic goose eggs over the course of a laying season. There was a significant change in the concentration of all three hormones: T and P4 increased in a linear manner across the season whilst A4 increased until mid season and then steadily decreased. The correlation between T and P4 (r = 0.613, P<0.001), and between T and A4 (r = 0.746, P<0.001) were both positive, but the relationship between A4 and P4, while positive was not strong (r = 0.379, P<0.001), although still significant. The increase in P4 over the laying season is consistent with the transition from a laying to a broody state. The increase in T is consistent with a trade-off for the seasonal decline in egg weight. [ABSTRACT FROM AUTHOR]

Abstract: Two types of model propose that strategic decisions during contests are determined either by (i) a mutual-assessment process or (ii) a self-assessment process. Vocal signals are thought to convey information about the competitive abilities of individuals, the ultimate function of which is a reduction in costs associated with fighting consistent with the principle of mutual assessment. Nevertheless, the limited evidence that male ungulates engage in mutual assessment of vocal rates during dyadic contests has been questioned. Therefore, we examined the vocal rates of winners and losers during escalated dyadic contests between male fallow deer in order to further inform on this issue. Our results showed that winners and losers did not differ in vocal rate. The best model fit that accounted for individual vocal rates included a preponderance of factors related to the opponent indicating that contestants were attending to their opponent during fights. Vocal rate was, therefore, dependent on estimates of opponent quality without reference to self, supporting an ‘opponent-only’ rather than a mutual assessment process. [Copyright &y& Elsevier]

The status of the pygmy shrew ( Sorex minutus L.) as a native or an introduced species in Ireland has been subject to much debate. To examine this and other aspects of the colonization history of the Irish pygmy shrew, genetic variation was determined in 247 pygmy shrews collected throughout Ireland, using mitochondrial control region sequences and five polymorphic microsatellite loci. Genetic diversity was low for both types of marker. The median-joining network for control region sequences was star-like, suggesting that the colonization of Ireland involved a small number of founders and rapid population expansion thereafter; this was supported by other statistics. Molecular dating with both mitochondrial DNA and microsatellite data is consistent with a human introduction. This would have been several thousand years ago; a recent colonization within historical times can be ruled out. This is the first detailed population genetic study of the pygmy shrew anywhere in its range. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 918–927. [ABSTRACT FROM AUTHOR]

Competitive interactions between mature male fallow deer were investigated to determine whether antler length, body weight, age or dominance rank were related to the number of fights between individuals. Four different hypotheses were tested; the first predicted that body weight and antler length indicate individual quality and, therefore, as the difference between competitors in body weight and antler length increases, there should be a corresponding decrease in fight rate. The second and third hypotheses predicted that, as difference in dominance rank increased there would be a decrease in fight rate between males either, as a risk reduction measure or because of inhibitory control by dominant males. A fourth hypothesis predicted that, where dominance rank does not mediate fight rate, that similarity between contestants based on age might be important. If this is the case, then as the difference in age between competitors increased there should be a decrease in fight rate. Our results show that when dominance rank is controlled for, there was no relation between body weight, antler length or age with fight rate. There was a negative relation between dominance rank difference and fight rate, a result that supports both the risk reduction and inhibitory hypotheses. There was an increasing tendency to fight with closely ranked males as cohorts reached peak reproductive age; males aged 5 yr fought with other 5-yr-old males based on rank difference and males aged 6 yr fought with other males aged six and across all age groups based on rank difference. This trend was not observed in 4 or 7-yr-old males. Our results suggest that males in prime breeding condition limit potential costs of fighting (such as time and energy) by only interacting with other males of similar rank. [ABSTRACT FROM AUTHOR]

Intense competition between males for reproduction has led to the evolution of alternative mating tactics (AMTs). Feral goat males usually use a tactic called tending, in which they defend oestrous females from other males. Males may also use a second mating tactic called coursing, in which they gain access to oestrous females by disturbing a tending pair. Herein, we examine estimated mating success (EMS) and risks of using these tactics. Tending was only used by mature (≥4 years old), higher-ranking males and accounted for 75% of EMS. Coursing was used by males of all ages and dominance ranks, and accounted for 25% of EMS. Using coursing, male kids achieved 8% of EMS. Mature males achieved 92% of EMS. Both age and dominance rank were related to EMS, but age was not important after its relationship with dominance was controlled. Tending bouts were, on average, ca. 30 min long, while coursing bouts only averaged ca. 2 min. Males were more likely to suffer a butt while coursing than while tending, and formerly tending males were responsible for most butts. Kids that coursed had the highest risk of being butted. In most AMTs, there are reductions in the risks in relation to low fitness benefits. However, we found that the risks of butts during coursing were high, while our evidence suggests that the EMS was probably low. Nevertheless, the existence of an effective AMT in male feral goats may have an important influence on the intensity of sexual selection and the effective population size. [ABSTRACT FROM AUTHOR]

An improved understanding of the decision rules used by competing animals can be achieved by examining both the temporal structure and display rate of competitors during a contest. Current models of animal competition make different predictions regarding the behaviour of competing animals and the present study evaluates the predictions of three such models, the energetic war of attrition (eWOA), the sequential assessment game (SAG) and the cumulative assessment model (CAM) by applying them to the fighting behaviour of male fallow deer (Dama damaL.). There was no difference in rate at which the jump clash and backward push were recorded over fight duration; therefore, in terms of the temporal distribution of behavioural acts within fights, the jump clash and backward push conformed to the predictions of the SAG. There was a difference between winners and losers of fights for the frequency that the jump clash and backward push were recorded consistent with both the SAG and CAM. Analysis of bout duration showed that there was a decrease in the duration of subsequent bouts of fighting; this is only permitted under eWOA. In so far as current assessment models permit interpretation of the data, our results meet only a limited number of predictions of any one model. Given the difficulty in interpreting our data within the context of current assessment models, recommendations for the development of more complex models are presented. [ABSTRACT FROM AUTHOR]

Fights between male fallow deer (Dama dama) may conclude with the contest decisively resolved in favour of one animal (the winner), or, there may be an inconclusive resolution, in which case there is no winner. We sought to compare the structure of fights between male fallow deer in order to determine what factors might be important in influencing how fights are concluded (i.e., decisively or inconclusively resolved). We compared differences in the number of backward pushes, jump clashes and retreats over fight duration; we also compared the duration of bouts of fighting. Fights that were decisively resolved had a significantly higher number of backward pushes and jump clashes than fights that were inconclusive. Decisively resolved fights also had a higher number of retreats in the final quarter of contests suggesting that, overall, fights that resulted in a winner were more costly than fights that were inconclusively resolved. There was a significantly larger asymmetry between opponents in decisively resolved fights in the proportion of backward pushes and jump clashes recorded suggesting that opponents in fights that ended inconclusively were more evenly matched. There was no difference in overall contest duration or the duration spent fighting between decisively and inconclusively resolved fights. These results indicate that the manner by which a contest concludes, is determined by the difference in action performance between contestants and also, a difference in the rate of behavioural actions as a function of time spent fighting. [ABSTRACT FROM AUTHOR]

We tested predictions of evolutionary game theory focusing on fight duration and intensity during contests between European fallow deer, Dama dama L. We examined the relation between contest duration and intensity and resource-holding potential (RHP; body weight and antler size), in an effort to reveal the assessment rules used by competing males. We examined other potential determinants of duration and intensity: resource value (the oestrous female) and experience of agonistic interactions. Asymmetry in body weight or antler length of contestants was not correlated with fight duration. Body weight and antler length of the fight winner or loser were also not correlated with fight duration. Neither were the body weight of the heavier or lighter animal or the antler length of the animal that had longer or shorter antlers. A measure of intensity (the jump clash) was positively related to the body weight of the losing animal and the lighter member of the dyad. These results are consistent with the hypothesis that opponents escalate contest intensity based on assessment of their own ability rather than through mutual assessment. There was no evidence that resource value is an important factor in either fight duration or intensity in this population. As the number of fights between pairs of males increased, there was a decrease in fight duration. Fights were longer when at least one member of a competing pair of males had previously experienced a victory. [Copyright &y& Elsevier]

During competitive encounters protagonists are expected to use signals of individual quality particularly if there is a risk of injury or death. Lateral presentation of body profile, by which information regarding phenotypic characteristics associated with individual quality are displayed, may represent such a strategy. During aggressive interactions, male fallow deer frequently engage in parallel walking which is assumed to represent a mutual display of quality, as mediated by exposure of the maximal profile of the body or antlers. We examined the context and role of the parallel walk during competitive encounters to investigate whether there was evidence that dyads of competing males were assessing differences in phenotypic characteristics. There was no evidence to support the hypotheses that the parallel walk is a lateral display of body size or weaponry or that its use is associated with a reduced level of escalated or risky behaviours during fighting. Total time spent fighting was not shorter when a parallel walk was present than when there was no parallel walk. The parallel walk was highly associated with fighting and it was more likely to be initiated by the subsequent loser. Furthermore, parallel walking frequently followed bouts of fighting and as such may represent a strategy that permits an animal the opportunity to decide whether to continue fighting. Parallel walking was also associated with a failure to resolve contests in favour of one animal indicating that it may be a means of withdrawing from further fighting without incurring a loss in dominance status. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour. [Copyright &y& Elsevier]

A central aim of the study of animal communication is to identify the mode and content of information transferred between individuals. The lateral presentation of the antler palm between male fallow deer has been described as either a signal of individual quality or an attempt to avoid fighting. In the first case two phenotypic features have been proposed by which transmission of individual quality may be facilitated. These are antler size and antler symmetry. The alternative hypothesis proposes that the lateral presentation of antlers occurs as a consequence of averting a threatening posture and may signify a reluctance to fight. We examined whether mature fallow deer use lateral palm presentation as a display during fights to indicate antler size and symmetry. We found no relationship between presentation rate of the antler and antler size and symmetry. Furthermore, males did not preferentially present their larger antler to their opponent. We also investigated whether the rate at which males presented antlers laterally during a fight was related to their ability to win the fight. Our results show that the male who performed more presentations during a fight was more likely to lose it. There were behavioural differences in the way in which a bout of presentation ended; subsequent losers tended to turn their body away from their opponent and subsequent winners tended to lower their antlers to an opponent which we interpret as an invitation to continue fighting. We conclude that the lateral palm presentation serves to de-escalate fighting between mature fallow deer. It is not a mechanism by which to communicate individual quality but rather an indication that a male is less committed to continuing investment in the current contest. [ABSTRACT FROM AUTHOR]

Studies fighting tactics of fallow bucks during the breeding season to determine if conflict strategies were consistent with the reduction of risk. Availability of mating opportunities; Frequency of fights; Increase in sexual dimorphism.