Monarch Migration News: June 4, 2015
By Elizabeth Howard
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The grandchildren of the monarchs from Mexico are developing now. How many generations will this summer yield?

Amy Evoniuk

News: Midwest Seeing the Action
As the northernmost monarchs approach latitude 48°N in the Midwest, the migration into the prime breeding region is nearing completion. Among the monarchs reported were:

a bright male sipping dew from the grass
a female feeding on a dandelion blossom
a faded butterfly laying eggs on poke milkweed
four eggs on six plants in a suburban garden

Stalled in Northeast
The migration is lagging behind in the northeast, where it's stalled at latitude 41°N. The distance to this region from Mexico always means a later arrival; this is the outermost extent of the breeding range.

Cold temperatures appears to be holding the butterflies back this year even more than normal as the comparative maps show. A delayed arrival will delay generations and allow less time for numbers to build. Monarchs may be more scarce than normal this summer. In the short life-span of a butterfly, single days or weeks can impact the population significantly.

Late-May Surge
Of the 12 week migration so far, 33% of the seasons sightings were reported during the last 2 weeks. This graph documents the late-May surge that represents the emergence and northward migration of the 1st spring generation. Thanks to the observations contributed by citizen scientists we know when this year's northern breeding season began and can estimate generation timing.

Counting Generations
Monarch generations are continuing to cycle. It takes about one month for each to develop. Over the summer, three generations will be produced in the north.

June: grandchildren

July: great-grandchildren

August: great-great-grandchildren—the generation that migrates to Mexico.

Monarch Butterfly Migration Maps
Compare Years

Monarch Butterfly Migration Sightings
Late-May Surge

Monarch Butterfly Egg
Grandchild Generation
Monarch Butterfly Migration Maps
Spotlight: Monarchs of the Pacific Northwest
Details of monarch migration in the Pacific Northwest are poorly known, says Dr. David James. Low populations of monarchs and people in the region have made migration difficult to study.

Recent observations along California's Trinity River reveal a migration pathway. The river concentrates the monarchs to detectable levels and makes tagging and studying possible.


Conservation News

White House Promotes Pollinator Health
A new national conservation strategy to help pollinators includes a goal to increase the monarch population to 225 million butterflies a 4-fold increase from last winter's 57 million.

How you can help Monarch Butterflies at Sanctuary in Mexico
Maps: Report Your Sightings
Monarch butterfly migration map Monarch butterfly migration map Map of milkweed emergence: Spring 2015
What to Report First Adult
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Monarch butterfly migration map Monarch butterfly migration map Monarch butterfly migration map
First Egg
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First Larvae
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Other Observations
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Journal and Activities
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Next Update June 11, 2015