Publications by authors named "Hirschenhauser K"

Behavioural flexibility plays a major role in the way animals cope with novel situations, and physiological stress responses are adaptive and highly efficient mechanisms to cope with unpredictable events. Previous studies investigating the role of stress responses in mediating behavioural flexibility were mostly done in laboratory rodents using stressors and cognitive challenges unrelated to the ecology of the species. To better understand how stress mediates behavioural flexibility in a natural context, direct manipulations of the stress response and cognitive tests in ecologically relevant contexts are needed.

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Employing living animals in educational settings is popular and may assist learning. Human-animal relationships are considered fundamental for the effects of animal-assisted interventions (AAI) on successful learning. Key studies on AAI emphasize dogs, or other large-brained vertebrates, while AAI with non-vertebrate species is a yet rather unexplored field.

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Background: Citizen science has evolved over the past decades by motivating members of the public to interact with scientists and actively participate in scientific research and monitoring. For this purpose, a proficient communication is mandatory in order to efficiently convey messages and reduce the gap of knowledge between scientists and lay people. In the present study, we aimed at evaluating the multiplying effect of children, who were trained to communicate their knowledge on an endangered bird species in order to engage the local community in the long-term ornithological monitoring of the free flying and individually marked colony of northern bald ibis (NBI, ), which was established at the research station in 1997.

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Beyond subject matter learning, primary science teaching aims at encouraging positive attitudes toward, and lasting interest in, science. This study tested whether the learning and science commitment of 8- to 10-year old pupils was affected by extracurricular learning opportunities involving repeated interactions with free-living northern bald ibis (Geronticus eremita; an endangered bird species) and professional researchers. To examine the project's efficacy, pupils' learning progress was monitored by repeated measures of knowledge (i) about northern bald ibises in specific, and (ii) of bird diversity in general.

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Aggression is a fundamental part of animal social behaviour. In avian species, little is known about its neural representation. In particular, neural activity following offensive aggression has not been studied in detail.

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Among vertebrates, winning a fight enhances the probability of future victories and vice versa and the role of post-conflict testosterone in mediating this 'winner effect' is widely accepted. In a series of staged fights of Japanese quail (Coturnix japonica) we tested both opponents' pre-fight and post-conflict testosterone, behavior and dominance status after returning to their social groups. We found that the presence of a familiar mixed-sex audience during the encounter modulated both the testosterone response and the long-term success after a fighting experience.

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Research on the diversity, evolution and stability of cooperative behaviour has generated a considerable body of work. As concepts simplify the real world, theoretical solutions are typically also simple. Real behaviour, in contrast, is often much more diverse.

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For successfully raising offspring, long-term monogamous pair partners need to be behaviorally and hormonally coordinated. In the monogamous, biparental greylag geese (Anser anser) a dyadic pairbond-specific measure, 'within-pair testosterone compatibility' (TC) indicated how closely synchronized are seasonal androgen levels, which co-varied with reproductive output. Males, in particular, were assumed to respond to their females' hormonal and fecundity phases.

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Ten novel polymorphic microsatellite loci were isolated and characterized from the greylag goose, Anser anser, a long-term monogamous and biparental bird. Additionally, five new primers pairs were designed based on previously published microsatellite locus sequences from closely related species. Multiplex polymerase chain reactions conditions were optimized for all 15 primer pairs.

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Tropical bird species usually have lower testosterone (T) levels during breeding than temperate species. However, the potential mechanisms behind the positive interspecific correlation between T and latitude remain unexplored. In a comparative study of more than 100 bird species, we examined whether social constraints during male-male competition arising from migration and breeding synchrony are responsible for the latitude effects.

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Testosterone regulates the expression of sexual and aggressive behavior in male vertebrates and treatments with testosterone may promote territorial aggression and winning in dyadic contests. Conversely, individual testosterone levels respond to sexual or aggressive interactions and the social environment. Post-conflict testosterone in winner males though appears to be more complex than simply reflecting conflict outcome.

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In the field as well as in the laboratory, human-generated stress responses are reduced in adult animals previously habituated to humans in comparison to non-habituated individuals. In birds, yolk steroid levels vary with maternal environment and condition. We tested the hypothesis that the experience of female birds with humans could affect yolk steroids levels and offspring phenotype.

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Lately, Emery et al. developed a bird-specific modification of the "social brain hypothesis", termed "relationship intelligence hypothesis". Although the idea may be valuable, we doubt that it is supported by sufficient evidence and critically discuss some of the arguments raised by the authors in favour of their new idea.

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The reliability of noninvasively measuring steroid hormones from feces in greylag geese (Anser anser) and domestic geese (A. domesticus), both qualitatively and quantitatively, was tested experimentally. Geese are mainly herbivorous birds with a short gut-passage time (2-3 h).

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Previous investigations suggest that male tropical birds have lower plasma testosterone concentrations than northern latitude species. To test whether this generalization is valid, we analyzed all currently available plasma testosterone data of tropical birds. We focused on peak breeding testosterone levels using phylogenetic and conventional statistics.

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Male androgen responses to social challenges have been predicted to vary with mating system, male-male aggressiveness, and the degree of paternal investment in birds ("challenge hypothesis," Am. Nat. 136 (1990), 829).

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The individual time patterns of salivary testosterone of adult healthy men, self-reported sexual behavior and their co-occurrence with regular weekly or monthly intervals were studied. Twenty-seven volunteer males (mean age 33 +/- 1 years) collected daily morning saliva over a period of 90 days. Evening questionnaires provided daily information on sexual activity.

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Androgens are classically thought of as the sex steroids controlling male reproduction. However, in recent years evidence has accumulated showing that androgens can also be affected by the interactions between conspecifics, suggesting reciprocal interactions between androgens and behaviour. These results have been interpreted as an adaptation for individuals to adjust their agonistic motivation and to cope with changes in their social environment.

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In two groups (eight individuals each) of socially acquainted, outdoor-kept, domestic ganders (male Hungarian white: Anser domesticus), basal and GnRH-stimulated plasma testosterone (T) concentrations were compared with fecal testosterone metabolites (TM) in and between three seasons, spring peak of reproductive activity, summer photorefractoriness, and fall sexual reactivation. Plasma was sampled 90 min following the challenge and T was analyzed by radioimmunoassay following the GnRH challenge. Fecal TM were measured by enzyme immunoassay using two group-specific antibodies against 17beta-OH-androgens or a novel antibody against 17-oxo groups, which was found to react with major testosterone metabolites without prior hydrolytic deconjugation.

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Seasonal patterns of fecal 17beta-OH-androgen, estrogen, and progesterone equivalents of male and female greylag geese (Anser anser) were analyzed in a flock of free-living geese. These were compared among social categories determined by pairbond status and breeding success. The annual cycle was divided into 13 phases.

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Studies of captive animals have suggested that social stress affects subdominants, whereas recent data from the wild have revealed that stress mainly affects dominants. We used a non-invasive approach to investigate, for the first time in a social bird, the circannual stress-dominance relationships between low-ranking single males, intermediately positioned paired ganders without offspring and high-ranking paired males with offspring from a flock of semi-tame, free-ranging greylag geese, Anser anser. We collected 933 faecal samples from 43 individuals, 12 singletons, 18 paired males without offspring and 13 paired males with offspring over an entire year and analysed them for corticosterone metabolites by enzyme immunoassay.

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