Infrasound and Avian Navigation

Jon's paper on infrasound as a major factor
in bird navigation is finally out!
Way to go Jon! Check out the abstract below.
Click for the complete paper। PDF download
With charts and graphs!

"The Case for Infrasound as the Long -Range

Map Cue in Avian Navigation"

by Jonathan T. Hagstrum, U.S. Geological Survey

ABSTRACT;
Of the various ‘map’ and ‘compass’
components of Kramer’s avian
navigational model, the long-range map
component is the least well understood.
In this paper atmospheric infrasounds are
proposed as the elusive long-range cues
constituting the avian navigational map.
Although infrasounds were considered a
viable candidate for the avian map in the 1970s, and pigeons in
the laboratory were found to detect sounds at surprisingly low
frequencies (0.05 Hz), other tests appeared to support
either of the currently favored olfactory or magnetic
maps. Neither of these hypotheses, however, is able to
explain the full set of observations, and the field has been
at an impasse for several decades. To begin, brief descriptions
of infrasonic waves and their passage through the atmosphere
are given, followed by accounts of previously unexplained
release results. These exam-ples include ‘release-site biases’
which are deviations of departing pigeons from the homeward
bearing, an annual variation in homing performance observed
only inEurope, difficulties orienting over lakes and above tem-
perature inversions, and the mysterious disruption of sev-
eral pigeon races. All of these irregularities can be con-
sistently explained by the deflection or masking of infra-
sonic cues by atmospheric conditions or by other infra-
sonic sources (microbaroms, sonic booms), respectively.
A source of continuous geographic infrasound generated
by atmosphere-coupled microseisms is also proposed. In
conclusion, several suggestions are made toward resolv-
ing some of the conflicting experimental data with the
pigeons’ possible use of infrasonic cues."

COMPLETE PAPER in PDF Download.