Cottage Q&A
QUESTIONI noticed a phenomenal number of monarch butterflies around the cottage this summer, more than ever before. What's the reason for this? I thought they were in decline because of loss of habitat and food.
ANSWER
"It has been a real banner year," says renowned field naturalist Don Davis. "The conditions for monarchs were just outstanding." Davis, who has been observing monarchs for 35 years, says butterfly populations have rebounded since 2002, when freezing temperatures in Mexico - where monarchs winter - killed up to 250 million of them and significantly reduced the number of butterflies migrating north. Davis says reports suggest that populations this year were particularly large in areas around Georgian Bay, Haliburton, and Muskoka.
Chris Darling, curator of insects at the Royal Ontario Museum, says that the number of monarchs in Canada is dependent on conditions in Mexico, as well as adequate temperatures and food supplies for their up to 4,500 km northern migration in late winter and spring and the journey back south in the fall. Along the northbound route, successive generations lay eggs and die, leaving offspring to continue the migration to Canada, where they spend the summer. In 2006, all conditions were ideal, resulting in the largest migration since 2001. In Canada, a bumper crop of milkweed, the sole food source for monarch larvae, as well as excellent weather, helped spread the butterflies as far northwest as Edmonton and as far east as Newfoundland. (Their usual habitat ranges from the southern Prairie provinces to Nova Scotia.) "Insects have a remarkable ability to reproduce if the conditions are right," says Darling. "And populations will rebound unless affected by a serious human-induced change, such as logging." You can expect monarchs to return to your cottage sometime around June. To track their progress, go to Journey North at www.learner.org/jnorth.
* Published in the November/December 2006 issue of Cottage Life
