Change search
ReferencesLink to record
Permanent link

Direct link
Avian migration: the role of geomagnetic cues
Stockholm University, Faculty of Science, Department of Zoology.
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The regularity and scale of bird migrations has impressed mankind for generations. Birds rely on an inherited migratory program to guide them during the journey; however, recent evidence suggests that additional external cues are necessary. This thesis concerns how migratory birds use information from the Earth’s geomagnetic field, the role it plays in locating the breeding area and as a cue affecting fuelling behaviour.

A displacement experiment with lesser whitethroats (Sylvia curruca) during spring migration indicates, for the first time, that birds include information from the geomagnetic field to locate their breeding area. Birds geomagnetically displaced south of the Swedish breeding area, exhibited consistent northerly orientation, close to the expected migratory direction. Birds displaced north, beyond their previous experience, failed to show a consistent direction of orientation. This suggests that they may have difficulty finding a direction in the absence of other compass cues.

Migratory birds must obtain enough fuel and in the right places, e.g. before an ecological barrier, if they are to complete the journey successfully. Young birds on their first migration must do this without previous experience of the journey ahead. Inexperienced thrush nightingales (Luscinia luscinia) increased fuel deposition as expected when given a magnetic field of northern Egypt, their last stopover before the Saharan barrier. A single step change in magnetic field to Egypt resulted in the same change in fuel deposition as previously shown with multiple steps. In contrast, European robins (Erithacus rubecula) experiencing a simulated migration to the wintering area in Spain, where no large fuel loads are needed, showed low fuel deposition rates. This suggests that geomagnetic field information does not produce a general response in fuel deposition in a manner, similar to the way day length triggers migratory activity in autumn, rather birds respond in a biologically relevant way for each species.

For both nightingales and robins the patterns of body mass change was unaffected by the time of season in birds experiencing the magnetic treatments. The magnetic field acts, therefore, as an important external cue, overriding the effect of season, helping birds make the right fuelling decisions along the migratory route. Furthermore, food intake was the major reason for the observed increase in fuelling rate compared to control birds. The finding that the magnetic field induces hormonal changes in thrush nightingales gives an indication of the underlying mechanism behind the food intake and resulting body mass changes seen in these experiments.


Place, publisher, year, edition, pages
Stockholm: Department of Zoology, Stockholm University , 2009. , 23 p.
Keyword [en]
geomagnetic cues, orientation, food intake, fuel deposition, corticosterone, endogenous time program, bird migration
National Category
Biological Sciences
Research subject
URN: urn:nbn:se:su:diva-27404ISBN: 978-91-7155-886-2OAI: diva2:216168
Public defence
2009-06-05, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 8 C, Stockholm, 10:00 (English)
Available from: 2009-05-14 Created: 2009-05-01 Last updated: 2009-05-07Bibliographically approved
List of papers
1. Food intake and fuel deposition in a migratory bird is affected by multiple as well as single-step changes in the magnetic field
Open this publication in new window or tab >>Food intake and fuel deposition in a migratory bird is affected by multiple as well as single-step changes in the magnetic field
Show others...
2008 (English)In: The Journal of Experimental Biology, Vol. 211, 649-653 p.Article in journal (Refereed) Published
urn:nbn:se:su:diva-14293 (URN)doi:10.1242/jeb.014183 (DOI)000253196600010 ()
Available from: 2008-08-15 Created: 2008-08-15 Last updated: 2014-10-28Bibliographically approved
2. Fuelling decisions in migratory birds: geomagnetic cues override the seasonal effect.
Open this publication in new window or tab >>Fuelling decisions in migratory birds: geomagnetic cues override the seasonal effect.
Show others...
2007 (English)In: Proceedings of the Royal Society of London B, Vol. 274, no 1622, 2145-2151 p.Article in journal (Refereed) Published
Abstract [en]

Recent evaluations of both temporal and spatial precision in bird migration have called for external cues in addition to the inherited programme defining the migratory journey in terms of direction, distance and fuelling behaviour along the route. We used juvenile European robins (Erithacus rubecula) to study whether geomagnetic cues affect fuel deposition in a medium-distance migrant by simulating a migratory journey from southeast Sweden to the wintering area in southern Spain. In the late phase of the onset of autumn migration, robins exposed to the magnetic treatment attained a lower fuel load than control birds exposed to the ambient magnetic field of southeast Sweden. In contrast, robins captured in the early phase of the onset of autumn migration all showed low fuel deposition irrespective of experimental treatment. These results are, as expected, the inverse of what we have found in similar studies in a long-distance migrant, the thrush nightingale (Luscinia luscinia), indicating that the reaction in terms of fuelling behaviour to a simulated southward migration varies depending on the relevance for the species. Furthermore, we suggest that information from the geomagnetic field act as an important external cue overriding the seasonal effect on fuelling behaviour in migratory birds.

magnetic cues, bird migration, fuelling decisions, magnetic cues, endogenous time programme
National Category
urn:nbn:se:su:diva-18096 (URN)doi:10.1098/rspb.2007.0554 (DOI)000248809600011 ()
Available from: 2007-10-17 Created: 2007-10-17 Last updated: 2014-10-28Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Henshaw, Ian
By organisation
Department of Zoology
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 145 hits
ReferencesLink to record
Permanent link

Direct link