Individual Variability in Experiments with Emlen Funnels

Marchetti, Chiara; Baldaccini, Natale Emilio

doi:10.1007/978-3-662-05957-9_28

Cited by 6 publications

(6 citation statements)

References 14 publications

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“…However, this depends on whether heightened overall activity levels covary with migration in the wild. Consequently, there is a need for further research on the relationship between Zugunruhe and other behavioural traits (Marchetti and Baldaccini , Nilsson et al ). In future genetic experiments on Zugunruhe , data should be collected on traits that shed light on the migratory context of behaviour (Noordwijk et al ).…”

Section: Discussionmentioning

confidence: 99%

Programmed and flexible: long‐term Zugunruhe data highlight the many axes of variation in avian migratory behaviour

Doren

Liedvogel

Helm

2017

Journal of Avian Biology

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Studies of Zugunruhe – the ‘migratory restlessness’ behaviour of captive birds – have been integral to our understanding of animal migration, revealing an inherited propensity to migrate and an endogenous timing and navigation system. However, differences between Zugunruhe in captivity and migration in the wild call for more data, in particular on variation within and among taxa with diverse migration strategies. Here, we characterise Zugunruhe in a long‐term dataset of activity profiles from stonechats (genus Saxicola) with diverse migratory phenotypes (976 migration periods from 414 birds), using a flexible and consistent quantitative approach based on changepoint analysis. For east African, Austrian, Irish, and Siberian stonechats and hybrids, we report key inter‐population differences in the occurrence, timing, and intensity of Zugunruhe. In line with expectations, we found the highest Zugunruhe intensity in the longest‐distance migrants, more variable patterns in short‐distance migrants, and intermediate characteristics of hybrids relative to their parental groups. Inter‐population differences imply high evolutionary lability of Zugunruhe timing within a robustly structured annual cycle. However, counter to theory, Irish partial migrants showed no segregation between migrant and resident individuals, and previously reported nocturnal restlessness was confirmed for resident African stonechats. Further features of nocturnal restlessness that did not align with migratory behaviour of stonechats were juvenile nocturnal restlessness even prior to postjuvenile moult, and protandry in spring, although stonechats winter in heterosexual pairs. Importantly, Zugunruhe of all populations declined with age, and the intensity of an individual bird's Zugunruhe was correlated with activity levels during other parts of the annual cycle. Our results confirm endogenous, population‐specific migration programmes but also reveal apparent discrepancies between Zugunruhe and migration in the wild. We thus highlight both the continued potential of Zugunruhe study and the need for circumspect interpretation when using migratory restlessness to make inferences about migration in the wild.

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Section: Discussionmentioning

confidence: 99%

Programmed and flexible: long‐term Zugunruhe data highlight the many axes of variation in avian migratory behaviour

Doren

Liedvogel

Helm

2017

Journal of Avian Biology

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“…Whenever we place birds in standardised experimental conditions, whether it is a respiration chamber, a cage to measure migratory restlessness or an orientation funnel, part of the consistent variation among individuals may be due to differences between personalities that are also described as pro-active and re-active strategies to cope with stress (Koolhaas et al 1999;Marchetti and Baldaccini 2003). Thus, personalities may interfere with the possibilities for measuring certain traits under standardised test conditions.…”

Section: Bird Personalitiesmentioning

confidence: 97%

“…Thus, personalities may interfere with the possibilities for measuring certain traits under standardised test conditions. It is quite likely that by discarding individuals that do not fly well in a wind-tunnel or that do not orient well in an Emlen-funnel, we systematically under-represent individuals on one end of the personality score axis (Marchetti and Baldaccini 2003). A second issue is that, in nature, personalities also greatly affect social interactions and learning.…”

Section: Bird Personalitiesmentioning

confidence: 98%

A framework for the study of genetic variation in migratory behaviour

et al. 2006

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Evolutionary change results from selection acting on genetic variation. For migration to be successful, many different aspects of an animal's physiology and behaviour need to function in a co-coordinated way. Changes in one migratory trait are therefore likely to be accompanied by changes in other migratory and lifehistory traits. At present, we have some knowledge of the pressures that operate at the various stages of migration, but we know very little about the extent of genetic variation in various aspects of the migratory syndrome. As a consequence, our ability to predict which species is capable of what kind of evolutionary change, and at which rate, is limited. Here, we review how our evolutionary understanding of migration may benefit from taking a quantitative-genetic approach and present a framework for studying the causes of phenotypic variation. We review past research, that has mainly studied single migratory traits in captive birds, and discuss how this work could be extended to study genetic variation in the wild and to account for genetic correlations and correlated selection. In the future, reactionnorm approaches may become very important, as they allow the study of genetic and environmental effects on phenotypic expression within a single framework, as well as of their interactions. We advocate making more use of repeated measurements on single individuals to study the causes of among-individual variation in the wild, as they are easier to obtain than data on relatives and can provide valuable information for identifying and selecting traits. This approach will be particularly informative if it involves systematic testing of individuals under different environmental conditions. We propose extending this research agenda by using optimality models to predict levels of variation and covariation among traits and constraints. This may help us to select traits in which we might expect genetic variation, and to identify the most informative environmental axes. We also recommend an expansion of the passerine model, as this model does not apply to birds, like geese, where cultural transmission of spatio-temporal information is an important determinant of migration patterns and their variation.

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“…Bagg et al 1950;Critchfield 1966;Kreithen and Keeton 1974;Richardson 1982;Dänhardt and Lindström 2001;ShamounBaranes et al 2006), and (5) cloud cover level (e.g. Mouritsen 1998a, b;Å kesson and Bäckman 1999;Koistinen 2000;Marchetti and Baldaccini 2003;Nilsson et al 2006) were all found to be correlated to migratory activity.…”

Section: Introductionmentioning

confidence: 92%

“…As a sixth category, only a few outdoor orientation cage experiments have been analysed in relation to weather so far, and these have concentrated mainly on the level of cloud cover (e.g. Mouritsen 1998a;Marchetti et al 1998;Å kesson and Bäckman 1999;Marchetti and Baldaccini 2003). All the studies mentioned above showed correlations and/or dependencies between weather factors and migratory activity.…”

Section: Introductionmentioning

confidence: 96%

Weather significantly influences the migratory behaviour of night-migratory songbirds tested indoors in orientation cages

2010

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Each year, millions of birds migrate from their breeding grounds to their overwintering sites and back. The success, duration and effort of such a long journey depend strongly on the meteorological parameters the birds encounter en route. The behaviour of free-flying migratory birds and those studied outdoors in orientation cages has been shown to be influenced by local weather factors. However, only a few, mostly descriptive, studies have analysed whether meteorological parameters should be considered when testing captive migratory birds indoors in orientation cages. Here, we used a statistical approach to analyse how meteorological parameters affect orientation performance in a night-migrating songbird, the garden warbler (Sylvia borin), when tested indoors in Emlen funnels. Our results show that the activity and directionality of the tested birds is influenced significantly by local atmospheric pressure. Together with previous studies, these results suggest that weather conditions have an impact on orientation behaviour even during indoor experiments. The findings emphasize the importance of mixing up and/or randomizing different conditions on any given night. Ideally, during any given test night, the same number of birds should be tested in each condition involved in a given study. Thereby, the documented weather effects will influence the results of all experimental groups equally.

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Individual Variability in Experiments with Emlen Funnels

Abstract: The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

Cited by 6 publications

References 14 publications

Programmed and flexible: long‐term Zugunruhe data highlight the many axes of variation in avian migratory behaviour

Programmed and flexible: long‐term Zugunruhe data highlight the many axes of variation in avian migratory behaviour

A framework for the study of genetic variation in migratory behaviour

Weather significantly influences the migratory behaviour of night-migratory songbirds tested indoors in orientation cages

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