Interactions in the flexible orientation system of a migratory bird

MIGRATING birds rely on interacting compass senses: magnetic, star, polarized light and perhaps Sun compasses1,2. During the development of orientation mechanisms, celestial rotation of stars at night3 and of polarized skylight patterns during the day time4 provide information about true compass directions that calibrates the direction of migration selected using the magnetic compass3–11. It might often be advantageous to adjust the magnetic preference by a geographic reference, especially at high northern latitudes where magnetic declination is large. Paradoxically, a magnetic preference so calibrated will be reliable only within a region of similar declination unless magnetic orientation remains open to calibration in older birds, something that earlier studies suggested was not the case1,2. We report here that in the Savannah sparrow (Passerculus sandwichensis) the same sort of calibration of magnetic orientation found in very young birds also occurs in older individuals exposed during the migration period to clear day and night skies within a shifted magnetic field.

[1]  Stephen T. Emlen,et al.  A TECHNIQUE FOR RECORDING MIGRATORY ORIENTATION OF CAPTIVE BIRDS , 1966 .

[2]  Klaus Schmidt-Koenig,et al.  Animal Orientation and Navigation , 1972 .

[3]  W. Wiltschko,et al.  The interaction of stars and magnetic field in the orientation system of night migrating birds. II. Spring experiments with european robins (Erithacus rubecula). , 1975, Zeitschrift fur Tierpsychologie.

[4]  W. Wiltschko,et al.  The interaction of stars and magnetic field in the orientation system of night migrating birds. I. Autumn experiments with European Warblers (gen. Sylvia). , 2010, Zeitschrift fur Tierpsychologie.

[5]  F. Moore.  Solar cues in the migratory orientation of the Savannah sparrow, Passerculus sandwichensis , 1980, Animal Behaviour.

[6]  V. Bingman.  Savannah sparrows have a magnetic compass , 1981, Animal Behaviour.

[7]  E. Batschelet.  Circular statistics in biology , 1981 .

[8]  V. Bingman.  Magnetic Field Orientation of Migratory Savannah Sparrows With Different First Summer Experience , 1983 .

[9]  F. Moore.  Integration of environmental stimuli in the migratory orientation of the savannah sparrow (Passerculus sandwichensis) , 1985, Animal Behaviour.

[10]  Mary Ann Rankin,et al.  Migration : mechanisms and adaptive significance , 1985 .

[11]  K. Able,et al.  An alternative method for the analysis of Emlen funnel data , 1986 .

[12]  V. Bingman.  Earth's magnetism and the nocturnal orientation of migratory European Robins , 1987 .

[13]  Magnetic Orientation and Celestial Cues in Migratory Orientation , 1990 .

[14]  K. Able,et al.  Ontogeny of migratory orientation in the savannah sparrow, Passerculus sandwichensis: calibration of the magnetic compass , 1990, Animal Behaviour.

[15]  Kenneth P. Able,et al.  Calibration of the magnetic compass of a migratory bird by celestial rotation , 1990, Nature.

[16]  P. Berthold,et al.  Orientation in Birds , 1991, Experientia Supplementum.

[17]  K. Able.  The development of migratory orientation mechanisms. , 1991, EXS.

[18]  W. Wiltschko,et al.  Migratory orientation of pied flycatchers: interaction of stellar and magnetic information during ontogeny , 1992, Animal Behaviour.

[19]  J. Kirschvink,et al.  Uniform magnetic fields and double-wrapped coil systems: improved techniques for the design of bioelectromagnetic experiments. , 1992, Bioelectromagnetics.

[20]  Kenneth P. Able,et al.  Daytime calibration of magnetic orientation in a migratory bird requires a view of skylight polarization , 1993, Nature.

[21]  K. Able.  Orientation cues used by migratory birds: A review of cue-conflict experiments. , 1993, Trends in ecology & evolution.