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Genov, P. W., & Kostava, V. (1993). Untersuchungen zur zahlenmäßigen Stärke des Wolfes und seiner Einwirkung auf die Haustierbestände in Bulgarien. Zeitschrift für Jagdwissenschaft, 39(4), 217–223.
Abstract: Die Untersuchung wurde in der Zeitspanne von 1984 bis 1988 durchgeführt. Es wurden die Protokolle des Staatlichen Versicherungsinstituts benutzt, die Angaben für Raubüberfälle von Wölfen auf Haustiere beinhalten (Tabelle 1). Außerdem wurden Angaben über die während dieser Zeitspanne erlegten Wölfe zusammengefaßt. Die Abschußzahlen lauten: 1984 – 163, 1985 – 147, 1986 – 179, 1987 – 211 und 1988 – 220 Tiere. Die Anzahl der in den einzelnen Gebirgen lebenden Wölfe wurde nach einer Umfrage festgestellt. Für die in Betracht kommenden Gebirge werden folgende Bestandszahlen angenommen: Rhodopen -- 60-80 Individuen, 189 bis 264 km2 pro Tier, Rila- und Piringebirge -- 60-80 Tiere, 109 bis 145 km2 pro Tier, Ossogowo-Belassiza Gebirgssystem -- 40-50 Individuen, 57-70 km2 pro Tier, West- und Mittelbalkan -- 35-38 Wölfe, 200 km2 pro Tier. Dazu kommen noch 10-15 Wölfe im Flußbecken von Beli Lom und etwa 20 Exemplare in Strandscha- und Sakargebirge. Insgesamt lebten in Bulgarien im Jahre 1988 etwa 260-330 Wölfe (Abb. 1).
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Henry, S., Fureix, C., Rowberry, R., Bateson, M., & Hausberger, M. (2017). Do horses with poor welfare show 'pessimistic' cognitive biases? Sci. Nat., 104(1), 8.
Abstract: This field study tested the hypothesis that domestic horses living under putatively challenging-to-welfare conditions (for example involving social, spatial, feeding constraints) would present signs of poor welfare and co-occurring pessimistic judgement biases. Our subjects were 34 horses who had been housed for over 3 years in either restricted riding school situations (e.g. kept in single boxes, with limited roughage, ridden by inexperienced riders; N = 25) or under more naturalistic conditions (e.g. access to free-range, kept in stable social groups, leisure riding; N = 9). The horses' welfare was assessed by recording health-related, behavioural and postural indicators. Additionally, after learning a location task to discriminate a bucket containing either edible food ('positive' location) or unpalatable food ('negative' location), the horses were presented with a bucket located near the positive position, near the negative position and halfway between the positive and negative positions to assess their judgement biases. The riding school horses displayed the highest levels of behavioural and health-related problems and a pessimistic judgment bias, whereas the horses living under more naturalistic conditions displayed indications of good welfare and an optimistic bias. Moreover, pessimistic bias data strongly correlated with poor welfare data. This suggests that a lowered mood impacts a non-human species' perception of its environment and highlights cognitive biases as an appropriate tool to assess the impact of chronic living conditions on horse welfare.
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Mori, E., Benatti, L., Lovari, S., & Ferretti, F. (2016). What does the wild boar mean to the wolf? European Journal of Wildlife Research, 63(1), 9.
Abstract: Generalist predators are expected to shape their diets according to the local availability of prey species. In turn, the extent of consumption of a prey would be influenced by the number of alternative prey species. We have tested this prediction by considering the wild boar and the grey wolf: two widespread species whose distribution ranges overlap largely in Southern Europe, e.g. in Italy. We have reviewed 16 studies from a total of 21 study areas, to assess whether the absolute frequency of occurrence of wild boar in the wolf diet was influenced by (i) occurrence of the other ungulate species in diet and (ii) the number of available ungulate species. Wild boar turned out to be the main prey of the wolf (49% occurrence, on average), followed by roe deer (24%) and livestock (18%). Occurrence of wild boar in the wolf diet decreased with increasing usage of roe deer, livestock, and to a lower extent, chamois and red deer. The number of prey species did not influence the occurrence of wild boar in the wolf diet. The wild boar is a gregarious, noisy and often locally abundant ungulate, thus easily detectable, to a predator. In turn, the extent of predation on this ungulate may not be influenced so much by the availability of other potential prey. Heavy artificial reductions of wild boar numbers, e.g. through numerical control, may concentrate predation by wolves on alternative prey (e.g. roe deer) and/or livestock, thus increasing conflicts with human activities.
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