Atmospheric conditions create freeways, detours and tailbacks for migrating birds

Journal of Comparative Physiology A, May 2017

The extraordinary adaptations of birds to contend with atmospheric conditions during their migratory flights have captivated ecologists for decades. During the 21st century technological advances have sparked a revival of research into the influence of weather on migrating birds. Using biologging technology, flight behaviour is measured across entire flyways, weather radar networks quantify large-scale migratory fluxes, citizen scientists gather observations of migrant birds and mechanistic models are used to simulate migration in dynamic aerial environments. In this review, we first introduce the most relevant microscale, mesoscale and synoptic scale atmospheric phenomena from the point of view of a migrating bird. We then provide an overview of the individual responses of migrant birds (when, where and how to fly) in relation to these phenomena. We explore the cumulative impact of individual responses to weather during migration, and the consequences thereof for populations and migratory systems. In general, individual birds seem to have a much more flexible response to weather than previously thought, but we also note similarities in migratory behaviour across taxa. We propose various avenues for future research through which we expect to derive more fundamental insights into the influence of weather on the evolution of migratory behaviour and the life-history, population dynamics and species distributions of migrant birds.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2Fs00359-017-1181-9.pdf

Atmospheric conditions create freeways, detours and tailbacks for migrating birds

J Comp Physiol A Atmospheric conditions create freeways, detours and tailbacks for migrating birds Judy Shamoun?Baranes 0 1 2 Felix Liechti 0 1 2 Wouter M. G. Vansteelant 0 1 2 0 Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam , P.O. Box 94248, 1090 GE Amsterdam , The Netherlands 1 Vansteelant Eco Research , Dijkgraaf 35, 6721 NJ Bennekom , The Netherlands 2 Department of Bird Migration, Swiss Ornithological Institute , Seerose 1, 6204 Sempach , Switzerland The extraordinary adaptations of birds to contend with atmospheric conditions during their migratory flights have captivated ecologists for decades. During the 21st century technological advances have sparked a revival of research into the influence of weather on migrating birds. Using biologging technology, flight behaviour is measured across entire flyways, weather radar networks quantify large-scale migratory fluxes, citizen scientists gather observations of migrant birds and mechanistic models are used to simulate migration in dynamic aerial environments. In this review, we first introduce the most relevant microscale, mesoscale and synoptic scale atmospheric phenomena from the point of view of a migrating bird. We then provide an overview of the individual responses of migrant birds (when, where and how to fly) in relation to these phenomena. We explore the cumulative impact of individual responses to weather during migration, and the consequences thereof for populations and migratory systems. In general, individual birds seem to have a much more flexible response to weather than previously thought, but we also note similarities in migratory behaviour across taxa. We propose various avenues for future research through which we expect to derive more fundamental insights into the influence of weather on the evolution of migratory behaviour and the life-history, population dynamics and species distributions of migrant birds. Birds; Biologging; Flight behaviour; Radar; Weather Introduction During migration, birds must contend with an environment which is highly dynamic in space and time, and they must do so efficiently. As birds can transverse hundreds to thousands of kilometres in a single flight, tens of thousands of kilometres within a migration season and perhaps hundreds of thousands of kilometres in a lifetime it may be easy to take for granted just how sophisticated the adaptations must be for dealing with such a complex environment, the aerosphere. Scientists have been studying the impact of weather on migration for decades (e.g. Smith 1917; Mackintosh 1949; Lack 1960a) . For the vast majority of the 20th century studies were often limited in their spatial scope due to the technical difficulties in monitoring migratory movements. These studies were often based on visual observations (Ferguson and Ferguson 1922; Lowery 1945; Beth 1961) or local radar systems (Lack 1960b; Nisbet and Drury 1968; Bruderer 1971; Gauthreaux 1971) (Fig. 1). While visual observations may have a restricted spatial extent, constant effort sites and observation networks created opportunities for long-term studies and enabled researchers to identify recurring patterns of migration and elucidate how birds respond to weather (Allen et al. 1996; Maransky et al. 1997; Shamoun-Baranes et al. 2006) . In recent decades new measurement and modelling techniques have greatly facilitated studying how birds respond to weather and what the consequences are for individuals or populations, facilitating a new age of research and discovery (Fig. 1). Biologging techniques enable researchers to study individual response to weather and other external factors along entire flyways (Fig. 2), over sea as well as over land (Gill et al. 2014; Vansteelant et al. 2015; Nourani et al. 2016; Weimerskirch et al. 2016) . With high resolution GPS tracking and additional sensors such as accelerometers or heart rate monitors it is increasingly feasible to measure fine-scale changes in flight behaviour and flight energetics in response to the aerial environment (Bishop et al. 2015; Sherub et al. 2016; Vansteelant et al. 2017a) . The use of operational weather radar networks, in some cases combined with citizen science based field observations, enable researchers to study migration phenology and altitudinal distribution in relation to weather over much larger areas than previously possible (Shamoun-Baranes et al. 2014; La Sorte et al. 2015b; Horton et al. 2016a) . Simulation modelling and biologging have created opportunities to study potential cumulative effects of behaviour for an individual as well as population level consequences of individual behaviour (Fig. 2) (Stoddard et al. 1983; Erni et al. 2005; McLaren et al. 2012) . Theoretical studies with analytical models have defined clear benchmarks or boundaries within which we expect migratory behaviour to occur generating hypotheses which can be tested in the field (Ale (...truncated)


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2Fs00359-017-1181-9.pdf

Judy Shamoun-Baranes, Felix Liechti, Wouter M. G. Vansteelant. Atmospheric conditions create freeways, detours and tailbacks for migrating birds, Journal of Comparative Physiology A, 2017, pp. 509-529, Volume 203, Issue 6-7, DOI: 10.1007/s00359-017-1181-9