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Effects of Variable Food Supply on the Body Condition of Breeding Tawny Owls <i>Strix aluco</i> in Southern Finland
Get PDFBody condition of boreal species of vole-eaters seems to vary in accordance with fluctuating vole populations. Tawny owls Strix aluco of temperate origin were studied to reveal if they show a similar pattern during nestling period near the northern limit of the species' range. The body condition of tawny owls was not considerably affected by the annual fluctuations of small voles indicated by regional vole indices and local prey samples. There were some significant relationships with some alternative prey but the variation in the body condition of owls was largely explained by the bird's age, time of the season, and stage of the nestling period. Old birds that bred earlier in the season were in better condition than young ones that bred later. Due to alternative prey, the body condition seemed to be relatively resistant to the effects of variable foraging conditions as expected for a generalist species of southern origin.</jats:p
Impact of Dominant Predators on Territory Occupancy and Reproduction of Subdominant Ones within a Guild of Birds of Prey
No full textVulnerability of Prey Species to Predation by Two Sympatric Accipitrine Hawks in Rural and Peri-Urban Landscapes in Southern Finland
No full textThis study assesses how the predation by the Eurasian sparrowhawk Accipiter nisus and the Eurasian goshawk Astur gentilis may affect the composition of prey communities breeding in rural and peri-urban landscapes. It asks how consistent the vulnerability of prey species is between different predator species and landscapes and which characteristics of prey species affect their vulnerability. Vulnerability of prey species to predation was characterised by the difference between the proportion of the prey species in the sample of prey items caught and the proportion of the species in the local pool of suitable prey. For both predators, vulnerability of shared prey species was positively related to vulnerability to predation between landscapes. Positive relationships between predators suggested that they prey independently from each other, while negative relationships suggest some interaction between predators. Higher vulnerability of shared prey species to sparrowhawk predation suggests that these species were less important prey for the goshawk. Effects of various characteristics of prey species on their vulnerability to predation varied to some extent between predator species and between landscapes. In particular, this was the case for sparrowhawk predation between rural and peri-urban areas. Prominent impact of prey body mass and population density on vulnerability to predation was highlighted
Timing of breeding in rural and urban Tawny Owls Strix aluco in southern Finland: effects of vole abundance and winter weather
No full textOwls’ Responses to Environmental Challenges
No full textOwls are a group of predatory birds characterized by their largely nocturnal way of life [...
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Body Condition in the Tawny Owl Strix aluco near the Northern Limit of Its Range: Effects of Individual Characteristics and Environmental Conditions
No full textThe body condition of boreal species of vole-eaters seems to vary largely according to fluctuations in vole populations and weather conditions of the preceding winter. I studied females and males of the Tawny Owl Strix aluco of temperate origin near the northern limit of the species’ range in southern Finland to reveal if they show similar patterns to the boreal species. Winter weather conditions before breeding seemed to have pronounced effects on the food availability of Tawny Owls. In females, intrinsic factors such as colour morph and age, as well as the body condition of the mate and the stage of the season (Julian date), governed body condition. In males, only age and Julian date showed pronounced relationships with body condition. The results suggest that deep snow cover protects vole populations through winter until spring better than a minor amount of snow and that frequent temperature fluctuations around the freezing point in early spring make voles more available for owls that are preparing for breeding. This was also reflected positively in the body condition of female owls. Probably due to the efficient use of alternative prey, the effects of fluctuating vole populations on the body condition of Tawny Owls are, in general, only moderate
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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