Thursday, September 18, 2014

Monarch Migration

Monarch emerged, dry and ready to take off
Chrysalis before emerging
As we watch the last of our monarch butterflies from Linda Bower emerge from their chrysalids to head south to Mexico, we are reminded of the challenges facing them.  First there is the emergence from the dried skin of the chrysalis itself.  They must hang on while pumping blood down into the veins of their deflated wings, expanding them with the help of gravity until they dry.  Falling or failure to hang properly can lead to deformity that sentences them to a brief stationary existence.

Failed wing expansion
Once their wings have dried and we release them from the rearing cage, they have to warm up their flight muscles, not easy on these last few cool, overcast rainy days.  Under these conditions they take off later and land earlier, frequently dependent upon the sun.   An observer from Ontario a few days ago reported, "We conservatively counted 1,000 monarchs from 11 a.m. to 2 p.m., at 4 - 8 per minute. Then the sun went behind clouds and all stopped!"*

Migration progress 9/17/2014 - Learner.org
You can follow the progress of migration thanks to citizen science reports on
Learner.org  including some day to day personal observations from Canada and the northern states as the migration begins.  The Learner.org maps show the day to day progress of the wave of monarchs heading to their winter quarters in Mexico.  Other maps show the location of adult butterflies, eggs and larvae, and fall roosts.

The migration of species has always been of interest to nature lovers, but now with the tools of the Internet, we have the ability to follow their journey.  Citizen scientists all over the US reporting their sightings of monarch butterflies and hummingbirds allows us to see the big picture as well as understand changing patterns of migration brought on by human activity and climate change.  Someday there may be tiny chips that allow us to follow the monarchs we raise.  Waaay too much information!

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