Manipulations of polarized skylight calibrate magnetic orientation in a migratory bird
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Young migratory birds enter the world with two representations of the migratory direction, one coded with respect to the magnetic field, the other with respect to celestial rotation. The preferred magnetic direction of migratory orientation is malleable early in life: it may be calibrated by celestial rotation, observed either in daytime or at night.
Previous experiments showed that early experience with skylight polarization was necessary for calilbration to occur in daytime. In this study, we performed a direct manipulation of patterns of polarized skylight at dawn and dusk.
Hand-raised Savannah sparrows (Passerculus sandwichensis) were allowed to observe the clear sky for 1 h prior to local sunrise and for one h following local sunset. They never saw the Sun nor stars. The birds observed the sky through bands of polarizing material (HNP'B) aligned with the e-vector axis in one of three orientations with respect of the azimuth of sunrise and sunset: group 1) 90°; group 2) 45° CW; group 3) 45° CCW.
Tested indoors in covered cages in both shifted and unshifted magnetic fields, the autumn migratory orientation of the three groups differed significantly. Group 1 oriented magnetic N-S, group 2 oriented magnetic NW-SE, and group 3 oriented magnetic NNE-SSW. These observed orientation directions are very close to those predicted by the manipulations of polarized skylight.
These results indicated that a fairly simplified, static polarized light pattern viewed a limited number of times only in dawn and dusk snapshots is sufficient to produce calibration of the preferred magnetic migratory orientation direction.
Key wordsMigratory orientation Magnetic orientation Polarized skylight Ontogeny Passerculus sandwichensis
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- Able KP (1982) Skylight polarization patterns at dusk influence the migratory orientation of birds. Nature 299: 550–551Google Scholar
- Able KP (1989) Skylight polarization patterns and the orientation of migratory birds. J Exp Biol 141: 241–256Google Scholar
- Able KP (1991) The development of migratory orientation mechanisms. In: Berthold P (ed) Orientation in birds. Birkhäuser, Basel, pp 166–179Google Scholar
- Able KP (1993) Orientation cues used by migratory birds: a review of cue-conflict experiments. Trends Ecol Evol 8: 367–371Google Scholar
- Able KP (1994) Magnetic orientation and magnetoreception in birds. Prog Neurobiol 42: 449–473Google Scholar
- Able KP, Able MA (1990a) Ontogeny of migratory orientation in the Savannah sparrow, Passerculus sandwichensis: calibration of the magnetic compass. Anim Behav 39: 905–913Google Scholar
- Able KP, Able MA (1990b) Calibration of the magnetic compass of a migratory bird by celestial rotation. Nature 347: 378–380Google Scholar
- Able KP, Able MA (1993a) Daytime calibration of magnetic orientation in a migratory bird requires a view of skylight polarization. Nature 364: 523–525Google Scholar
- Able KP, Able MA (1993b) Magnetic orientation in the Savannah sparrow. Ethology 93: 337–343Google Scholar
- Batschelet E (1981) Circular statistics in biology. Academic, New YorkGoogle Scholar
- Bingman VP (1983) Magnetic field orientation of migratory naive Savannah sparrows with different first summer experience. Behaviour 87: 43–53Google Scholar
- Bingman VP, Beck W, Wiltschko W (1985) Ontogeny of migratory orientation: a look at the pied flycatcher, Ficedula hypoleuca. In: Rankin MA (ed) Migration: mechanisms and adaptive significance. Contrib Marine Sci, Suppl, vol 27, Marine Science Institute, Univ Texas, AustinGoogle Scholar
- Brines ML (1980) Dynamic patterns of skylight polarization as clock and compass. J Theoret Biol 86: 507–512Google Scholar
- Cherry JD, Able KP (1986) An alternative method for the analysis of Emlen funnel data. Auk 103: 225–227Google Scholar
- Emlen ST (1970) Celestial rotation: its importance in the development of migratory orientation. Science 170: 1198–1201Google Scholar
- Emlen ST, Emlen JT (1966) A technique for recording migratory orientation of captive birds. Auk 83: 361–367Google Scholar
- Goddard SM, Forward RB (1991) The role of the underwater polarized light pattern, in sun compass navigation of the grass shrimp, Palaemonetes vulgaris. J Comp Physiol A 169: 479–491Google Scholar
- Helbig AJ (1990) Depolarization of natural skylight disrupts orientation of an avian nocturnal migrant. Experientia 46: 755–758Google Scholar
- Helbig AJ (1991) Dusk orientation of migratory European robins, Erithacus rubecula: the role of sun-related directional information. Anim Behav 41: 313–322Google Scholar
- Helbig AJ, Wiltschko W (1989) The skylight polarization patterns at dusk affect the orientation behavior of blackcaps, Sylvia atricapilla. Naturwissenschaften 76: 227–229Google Scholar
- Kirschvink JL (1992) Uniform magnetic fields and doublewrapped coil systems: improved techniques for the design of bioelectromagnetic experiments. Bioelectromagnetics 13: 401–411Google Scholar
- Merritt R, Purcell C, Stroink G (1983) Uniform magnetic field produced by three, four, and five square coils. Rev Sci Instruments 54: 879–882Google Scholar
- Moore FR (1986) Sunrise, skylight polarization, and the early morning orientation of night-migrating warblers. Condor 88: 493–498Google Scholar
- Moore FR, Phillips JB (1988) Sunset, skylight polarization and the migratory orientation of yellow-rumped warblers (Dendroica coronata). Anim Behav 36: 1770–1778Google Scholar
- Phillips JB, Moore FR (1992) Calibration of the sun compass by sunset polarized light patterns in a migratory bird. Behav Ecol Sociobiol 31: 189–193Google Scholar
- Phillips JB, Waldvogel JA (1982) Reflected light cues generate the short-term deflector-loft effect. In: Papi F, Wallraff HG (eds) Avian navigation. Springer, Berlin, pp 190–202Google Scholar
- Phillips JB, Waldvogel JA (1988) Celestial polarized light patterns as a calibration reference for sun compass of homing pigeons. J Theoret Biol 131: 55–67Google Scholar
- Prinz K, Wiltschko W (1993) Migratory orientation of pied flycatchers: interaction of stellar and magnetic information during ontogeny. Anim Behav 44: 539–545Google Scholar
- Waldvogel JA, Phillips JB (1991) Olfactory cues perceived at the home loft are not essential for the formation of a navigational map in pigeons. J Exp Biol 155: 643–660Google Scholar
- Wiltschko W, Baum P, Fergenbauer-Kimmel A, Wiltschko R (1987) The development of the star compass in garden warblers, Sylvia borin. Ethology 74: 285–292Google Scholar
- Wiltschko W, Wiltschko R (1991) Magnetic orientation and celestial cues in migratory orientation. In: Berthold P (ed) Orientation in birds. Birkhäuser, Basel, pp 16–37Google Scholar