• [2013-02-21] Research shows that coldness triggers northward flight in migrating monarch butterflies
  + http://www.cell.com/current-biology/abstract/S0960-9822%2813%2900087-0 + http://www.eurekalert.org/pub_releases/2013-02/cp-fmt021313.php
  in Tietoukka Monitor > 2013 > 2013-08 with migratory_butterflies temperatures

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