Monarch Butterfly Migration Update

Monarch Butterflies

Monarch Butterfly Update: March 1, 2012

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Your Sightings!

The first migrating monarchs have been seen, and the millions remaining are running low on fuel. March is here and it's a time of great change. Do you have questions about monarchs? Ask the Expert is now open.

This Week's Update Includes:

News: Spring is Coming, Fuel is Falling
Slideshow: No Food for Five Months?
The Migration: Maps and Journal

Image of the Week

Monarch Butterfly expert Dr. Karen Oberhauser

Ask the Expert

News: Spring is Coming, Fuel is Falling

First Butterflies Coming!
The first of sign of migration was just reported from the northern edge of the sanctuary region:

February 29: "Here come the monarchs! I observed a good number of butterflies migrating toward the north yesterday. I was able to see them on the stretch of road between Contepec and Maravatio," reports biologist Eligio Garcia, courtesy of Rocio Trevino.

Many millions of monarchs will remain at the sanctuaries until mid-to-late March, but this is the first sign of departure. With each passing day, the mass exodus is getting closer. Temperatures are rising. Monarch activity is at a frenzy on warm, sunny days. Mating increases dramatically now, and the butterflies are leaving their clusters continually to head out in search of water.

Fuel is Falling
The monarchs are running low on fuel. Look at the falling lipids on this line graph based on Dr. Lincoln Brower's research. How much longer could the monarchs stay in Mexico before they'd run out of fuel? Running out of fat is a common cause of mortality. Many monarchs simply starve.

Drought and Lipids
Lipid levels are of particular concern this year because of the drought in Texas and northern Mexico. Last fall, little nectar was available when monarchs traveled through that drought-stricken habitat. Normally, the butterflies would eat hungrily in that region to gain lipids for migration and winter survival. Scientists have been concerned whether monarchs would have enough lipids in reserve to sustain them this winter.

Recovering Tags
This week, Estela traveled with volunteers from Monarch Watch to gather tags people have found in the oyamel forest. "Some people brought only 2 tags but some brought many more, as many as 100. These were tags found during the previous winter. Sharing this couple of days with Diane and Debbie from Monarch Watch has been one of the most enriching experiences I have had in my education about the monarch's life and migration," reports Estela.