Table of Contents
Great Circle Hypotheis
Compass Bearings Hypothesis
Suns' Azimuth Hypothesis
Always Advance Hypothesis
Never Go Back Hypothesis
A Calculated Kiepenheuer and Schmidt-Koenig Magnetoclinic Late Summer and Fall Migration Route for Eastern
Population of Monarch Butterflies
Mississauga, Ontario, Canada, in Lower Great Lakes Region used as Starting Point
Drawing by Diane Scott
- Joined arrows indicate one possible Kiepenheuer and Schmidt-Koenig Magnetoclinic late
summer and fall migration route from lower Great Lakes region (i.e. Mississauga,
- Grey stippled region indicates area of overwintering sites.
- Numbers along top margin are degrees of longitude.
- Numbers on left margin are degrees of latitude. Parallels of latitude are not shown
but extend horizontally across drawing - note 49th parallel at Canada/US border.
- Numbers along right margin are isoclinic lines of of equal magnetic inclination (dip angle).
- Dashed lines radiating from top are isogonic lines of equal magnetic declination (variation).
- Agonic (i.e. making no angle) line running from panhandle of Florida to
western tip of Lake Superior. All compass bearings taken along the Agonic line are
equivalent to true bearings.
- The dashed line labelled 20° located to the left of the Agonic line is the 20°E
isogonic line. A compass bearing taken at any point along this line will be 20° greater
than true bearing (subtract to get true).
- The dashed line labelled -20° located to the right of the Agonic line is the 20°W
isogonic line. A compass bearing taken at any point along this line will be 20° less than
the true bearing (add to get true).