the mystery of Vanessa unidirectional migration

[Ernest Mengersen]

Two additions to Patrick Foley's references are:

Myres, M. T.  1985.  A southward return migration of painted lady butterflies, Vanessa cardui, over southern Alberta in the fall of 1983, and biometeorological aspects of their outbreaks in North America and Europe.  Canadian Field-Naturalist 99(2): 147 - 155.  

Nelson, R. Wayne.  1985(?).  Southward Migration of Painted Ladies in Alberta and British Columbia.  Blue Jay 43: 7 15.

Both are Canadian publications so may be difficult to find in the U.S.  If I remember correnctly, someone on the west coast was doing some research on this topic last spring.  Can anyone fill us in.  Also, I have observed them heading south in late July, early August in high population years but the southward migration is definitely not as spectacular.

Ernest

Ernest


 
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