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- Kullberg, Cecilia, et al.
(author)
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An experimental study of predator recognition in great tit fledglings
- 2002
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In: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 108:5, s. 429-441
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Journal article (peer-reviewed)abstract
- Studies of naturally predator-naïve adult birds (finches on predator-free islands) and birds experimentally hand reared in isolation from predators indicate that birds can recognise predators innately; that is, birds show anti-predator behaviour without former experience of predators. To reduce predation risk efficiently during the vulnerable fledgling period, we would predict an innate response to be fully developed when the chicks leave the nest. However, 30-day-old naïve great tit fledglings (Parus major) did not respond differently to a model of a perched predator than to a similarly sized model of a non-predator. Although chicks showed distress responses such as warning calls and freezing behaviour, they did not differentiate between the stimuli. In contrast, wild-caught first-year birds (4 mo old) and adults responded differentially to the two stimuli. Lack of recognition of a perched predator might be one explanation for the high mortality rate found in newly fledged great tits. Our results imply that parental care is not only important for food provisioning, but also to reduce predation risk during the time when fledglings are most vulnerable
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- Kullberg, Cecilia, et al.
(author)
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Magnetic cues and time of season affect fuel deposition in migratory thrush nightingales (Luscinia luscinia)
- 2003
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In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 270:1513, s. 373-378
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Journal article (peer-reviewed)abstract
- Bird migration requires high energy expenditure, and long–distance migrants accumulate fat for use as fuel during stopovers throughout their journey. Recent studies have shown that long–distance migratory birds, besides accumulating fat for use as fuel, also show adaptive phenotypic flexibility in several organs during migration. The migratory routes of many songbirds include stretches of sea and desert where fuelling is not possible. Large fuel loads increase flight costs and predation risk, therefore extensive fuelling should occur only immediately prior to crossing inhospitable zones. However, despite their crucial importance for the survival of migratory birds, both strategic refuelling decisions and variation in phenotypic flexibility during migration are not well understood. First–year thrush nightingales (Luscinia luscinia) caught in the early phase of the onset of autumn migration in southeast Sweden and exposed to a magnetic treatment simulating a migratory flight to northern Egypt increased more in fuel load than control birds. By contrast, birds trapped during the late phase of the onset of autumn migration accumulated a high fuel load irrespective of magnetic treatment. Furthermore, early birds increased less in flight–muscle size than birds trapped later in autumn. We suggest that the relative importance of endogenous and environmental factors in individual birds is affected by the time of season and by geographical area. When approaching a barrier, environmental cues may act irrespective of the endogenous time programme.
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- Lindholm, Cecilia, 1960-
(author)
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Ansvarighet och redovisning i nätverk : En longitudinell studie om synliggörande och osynliggörande i offentlig verksamhet
- 2003
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Doctoral thesis (other academic/artistic)abstract
- Making fundamental changes in the accounting systems of public-sector organisations and introducing management accounting models in those organisations constitutes not only a change in accounting techniques, but more importantly, causes major changes in the processes within which accountability is constructed through interaction between actors. When the use of management accounting methods in the public sector occurs, fundamental ideas about public sector activities change. This study draws upon the distinction between accounting systems as they are supposed to be used in the public sector and systems of accountability as these developed in practice. Accountability is constructed through processes, and studying accountability involves focusing on what is made visible, as well as concealed, in the interaction between actors over time. The aim of this processual study was to analyse the processes of accountability over a period of seven years, between 1987 and 1994. The arena of the study was three functionally distinct relationships between three actors connected by intraorganisational and interorganisational relationships. The study uses a multidimensional concept of relationships, since the relationships consist of actors connected by bonds, linked activities, and resource ties. Main conclusion of the study is the theoretical stand that formal accounting system is important as the actors construct accountabilities if there is a contemporaneous shortage of financial resources. In a situation with financial surplus, accountability is constructed according to the actor’s professional ideas and guidelines. The main conclusion is the development of the concept network of accountability as an extension and deepening of the concept system of accountability.
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