[Leps-l] Joe Billings Discovers Monarchs Are True Navigators

Paul Cherubini monarch at saber.net
Wed Dec 4 13:28:26 EST 2013

Earlier this year Rachael Derbyshire, a Canadian graduate student, and
her faculty advisers concluded, based on flight testing in an artificial flight 
http://imageshack.com/a/img28/4354/ybo7.jpg that fall migrant monarchs 
are not true navigators 
Here's an 8 minute interview with Rachael where she describes how 
fall migrants she tested in the flight simulator in Ontario headed southwest 
towards Mexico. She then drove them to Calgary, Alberta, tested them
again and found they still oriented to the southwest. So she and her
faculty advisers concluded fall migrants are not true navigators because
after being transported to Calgary the butterflies failed to head 
southeast in the flight simulator, towards their final overwintering destination 
in central Mexico http://www.cbc.ca/quirks/media/2012-2013/qq-2013-04-13_03.mp3

But this fall as well as in 2008 and 2010, a self-taught naturalist, Joe Billings 
of Vail, Arizona http://imageshack.com/a/img22/3729/2ksr.jpg
acquired tagging evidence that shows fall migrants are not behaviorally
locked into flying southwest or in other southerly directions in the fall to
find the refrigerator-like climates where they overwinter.  The nearest
refrigerator-like winter climate to southeastern Arizona is the central
California coast and Joe found that fall migrants tagged in southeastern 
Arizona during the first three weeks of September routinely fly northwest to
the overwintering sites along the cold central California coast, hence they 
are true navigators. In other words, Joe's butterflies were capable of 
orienting themselves in northwesterly directions - in the autumn - towards 
a geographical region that is thermally suitable for keeping them alive 
during the fall and winter months.

Specifically, two of a mere 51 fall migrants Joe tagged on Sept. 20, 2013
at Elgin, Arizona (near the Mexican border) were resighted at 
overwintering sites on the central California coast in October and November, 
hence there can be little reasonable doubt that most of them flew northwest
to the central California coast http://imageshack.com/a/img23/1631/0lcq.jpg

Weather history data from http://www.wunderground.com/history/ 
suggests Joe's butterflies battled westerly headwinds or northerly 
and southerly crosswinds during most of the journey to the central California

Surface winds: 
Sept. 20: http://imageshack.com/a/img545/7279/c4z3.jpg
Sept. 21: http://imageshack.com/a/img27/2074/tr8g.jpg
Sept. 22: http://imageshack.com/a/img14/6921/5pkd.jpg
Sept. 23: http://imageshack.com/a/img856/5635/2yz8.jpg
Sept. 24: http://imageshack.com/a/img30/5476/cr86.jpg
Sept. 25: http://imageshack.com/a/img849/1089/9h7x.jpg

To date, true navigation has been shown in only a few invertebrates
such as the eastern newt, the loggerhead sea turtle and the spiny lobster.

Paul Cherubini
El Dorado, Calif.

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