Model of acoustic propagation based on actual meteorological data between the Cornell loft in Ithaca, NY, USA (right edge of plot) and the Jersey Hill experimental release site (left edge of plot) on the one day that Cornell pigeons were well oriented there (inset circular diagram) and returned normally to the loft. Usually, Jersey Hill is in an acoustic ?shadow? zone relative to the loft, but on this day infrasonic signals were transmitted directly from the loft area to this release site due to abnormal atmospheric conditions.

Birds can navigate accurately over hundreds to thousands of kilometres. Their senses outnumber those of humans and can detect small changes in barometric pressure and the weak geomagnetic field. Pigeons can hear very low frequency infrasound, signals that can travel for thousands of kilometres in the atmosphere. Jon Hagstrum discusses how birds might use natural infrasonic signals for long-range navigation. The evidence supporting this hypothesis comes from locations where birds become disoriented in acoustic shadow zones, and the disruption of pigeon races by sonic booms.

Conference