Invisible Forces: Magnetism and Migration
The latest Slam Skillet release crafts a sailing uniform with imagery from marine birds. Just as the wind guides sailboats with an invisible force, the earth’s ever-shifting magnetic field influences the migrating behaviors of bird species. Avian orientation systems rely on the sun and stars to guide them along their seasonal journey. Until fairly recently, ornithologists were hesitant to group geomagnetism as a legitimate factor in orientation. In 1958, Franz and Eleanore Sauer developed an experiment that documented movement during migratory restlessness (a sudden and pressing urge to migrate). An bird was placed in a funnel of blotting paper, its feet touching an ink pad. When the bird attempted to fly towards its goal, its feet scuffed a certain portion of the funnel. Sauer recorded these data across many individuals and drew composite graphs that show directionality and intensity of orientation.
By the early 1970s, experiments by William Keeton, Charles Walcott, and Robert Green supported the hypothesis that birds use the earth’s magnetic topography for migratory orientation. Pigeons wearing bar magnets were thrown off their bearings in overcast conditions compared to a control group wearing brass bars. To supplement Keeton’s study, Walcott and Green attached Helmholtz coils to the heads of homing pigeons, generating an artificial magnetic field that altered the outcome of orientation. The bird’s response to the earth’s magnetic field is rooted in anatomy. Photopigments in the eye respond to poleward or equatorward angles of inclination, and guide flight direction. Magnetite receptors in the opthamalic branch of the trigeminal nerve cue an individual’s position, relative to its destination.
In the Slam Skillet Sailing Tee, Sauer’s diagrams are used to build a logo for a sailing uniform. The five interlocking rings resemble the symbol for the Olympic Games and corporate sponsors of sailing teams. Racing decals on the left sleeve and back contain the silhouette of an albatross, nestled between two Slam Skillet monograms. The Wandering Albatross has the largest wingspan of any extant bird (3.5 meters) and is a symbol of long-distance flight over open ocean.