PENINSULA GEOLOGICAL SOCIETY

Presents

Jonathan T. Hagstrum, U.S. Geological Survey

The Geophysical Basis of Avian Homing and Migration: Infrasonic Map Cues Coupled to the Atmosphere from Microseismic Waves

  • DINNER MEETING - Tuesday, May 13, 2008

    • Location: Stanford University

  • 5:30 PM-Social (3/4) Hour: . . . Hartley
  • 6:15 PM-Dinner: . . . Hartley
  • 7:30 PM-Meeting: . . . GeoCorner Room 320-105

    see Map showing Mitchell and GeoCorner Room 320

    Anyone wishing to attend the lecture only is welcome at no cost.

    This will be the 397th meeting since 1954

    Abstract

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    Transmission of infrasound (0.14 Hz) from the Cornell University pigeon loft near Ithaca, NY, north to the site of a successful release at Weedsport, NY, on September 21, 1972.

    After more than 50 years of intensive biological study, the ability of homing and migratory birds to navigate over great distances remains a mystery. Natural infrasounds (low-frequency acoustic waves) have been considered as possible map cues, but no perennial geographic source has been identified and no supporting evidence of its actual use has been found. Laboratory tests, however, show that pigeons (the experimental subject of choice) can detect sounds down to at least 0.05 Hz, and infrasounds can travel over several thousand km in the atmosphere with relatively little attenuation. Other experimental results have been interpreted as supporting either of the currently favored concepts of birds using olfactory or magnetic map cues. Neither of these hypotheses, however, can explain common observations from homing release experiments, and the field has been at an impasse for several decades. In this talk, a brief description of infrasonic waves and their passage through the atmosphere will be given, followed by accounts of previously unexplained release results. These examples include ‘release-site biases’ which are regular deviations of departing pigeons from the homeward bearing, an annual variation in homing performance observed only in Europe, difficulties orienting above temperature inversions and over lakes, and the perplexing disruption of pigeon races in the eastern United States and Europe. All of these irregularities can be consistently explained by the deflection or masking of infrasonic map cues by atmospheric conditions and topography or by other infrasonic sources (oceanic microbaroms, sonic booms), respectively. Results from an acoustic ray-tracing program using atmospheric rawinsonde data will also be presented in support of the acoustic-signal explanations. In conclusion, a perennial source of geographic infrasound generated by atmosphere-coupled microseisms, consistent with the available evidence, will be proposed.

    About the Speaker

    passport-style photo of Jon

    Jon Hagstrum was graduated with a BA in Geology in 1976 from Cornell University, an MS in Geology in 1979 from the University of Michigan, and a Ph.D. in 1985 from Stanford University. Since 1979 he has worked as a research geophysicist with the USGS at Flagstaff, Ariz., Denver, Colo., and, beginning in 1981, Menlo Park, Calif. His body of work lies primarily within the fields of paleomagnetism, rock magnetism, geomagnetism and plate tectonics.

    Reservations: The preferred way to make reservations is simply to email John Spritzer at jspritzer@usgs.gov by May 9, tell him you will attend, commit to pay, and bring your payment to the meeting. John always emails a confirmation; if you don’t get one, assume email crashed yet again and email him a second time. A check made to “PGS” is preferred, payable at the meeting.

    If you want to pay in advance:

    Everyone (including Stanford folks now) Please make dinner reservations by May 9. Contact John Spritzer, at U.S. Geological Survey, 345 Middlefield Road, MS-973 Menlo Park, CA 94025, Tel.: (650) 329-4833. Send check made out to “PGS” to John.

    Dinner is $30.00. Includes wine (5:30 to 6:15 PM.) and dinner (6:15-7:30 PM.).

    For students from all universities and colleges, the dinner, including the social 3/4-hour, is $5.00 and is partially subsidized thanks to the School of Earth Sciences, Stanford University (Note, no-show reservations owe the full price).

    Doris, whose wonderful crew prepares our meals, asked that we let you know that people who are late RSVPing and people who show up without a reservation will be welcome but that they will be eating on paper plates with plastic utensils (food supply permitting).

    Dues for Academic Year 2007-2008 ($10.00) should be sent to John Spritzer, U.S. Geological Survey, 345 Middlefield Road, MS-973 _Menlo Park, CA 94025. John’s phone: (650) 329-4833.

    Officers: Tom Moore, President; Keith Howard, Vice President; Mike Diggles, Secretary; John Spritzer, Treasurer; Elizabeth Miller, PGS Stanford University Coordinator

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    Date created: April 29, 2008
    Last modified: April 30, 2008
    Created by: Mike Diggles, Webmaster-Secretary, PGS.

    c/o U.S. Geological Survey, MS-951, 345 Middlefield Road, Menlo Park, CA 94025. (650) 329-5404. email Mike Diggles at mdiggles@usgs.gov

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