Tom's Blog

Wednesday, September 9, 2015

Tagging migrating Monarch butterflies

The Monarch butterfly (Danaus plexippus) is unique because of its long-range seasonal migration. The late-summer eastern North America populations migrate alll the way to central Mexico, where they overwinter. In the spring, the same individuals migrate to Texas or Oklahoma where they mate and produce a second generation, which migrates further north. Third and fourth generations may continue the northern migration before the butterflies finally settle for the rest of the summer in breeding grounds such as southern Wisconsin. 

Monarchs lay their eggs exclusively on milkweeds. We have lots of milkweeds at Pleasant Valley Conservancy, and hence lots of Monarchs.

In early September, the mature individuals prepare for the long southern migration. Although the return trip is long and arduous, significant numbers of individuals do complete the journey, where they overwinter in the Mariposa Monarca Biosphere Reserve (Michoacan province). 

Tracking this migration as part of a widespread butterfly conservation movement is an organization based in Lawrence, Kansas called Monarch Watch. Madison Audubon Society is cooperating with Monarch Watch and managing the tagging of Monarch butterflies in our area. The local headquarters for the tagging operation is at the MAS Goose Pond Sanctuary (Mark and Sue Martin). 

This is the second year that Kathie and Pleasant Valley Conservancy have been cooperating with MAS and Monarch Watch. Although catching and tagging Monarchs is not easy, today Kathie caught and tagged four Monarchs at PVC, three in the area of the East Basin and Ridge Prairie, and the fourth at the Pocket Prairie. All were successfully tagged and released!

The tags are small light-weight paper disks that contain a harmless adhesive.
After catching the butterfly in a net (the hardest part of the operation),
one of the numbered tags is picked  up with a toothpick.

Placing the tag on the butterfly's wing.
At this stage the sex of the butterfly is noted for the record.

The probability of a tagged butterfly reaching the Mariposa reserve is low, and the probability is even lower that someone might spot the tag and report it to Monarch Watch. Even so, at least one Monarch tagged at Goose Pond Sanctuary has been reported from Mexico. A $5 reward is given to anyone reporting a tagged butterfly.

Releasing the tagged butterfly.
The tagging operation does not harm the butterfly.


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