Monarch Butterfly News: September 5, 2013
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Numbers are down, but monarchs are on their way to Mexico, flying, nectaring, and roosting. Image of the Week
Monarch Butterfly
Helping Monarchs

Anna Letaw
News: Signs of Migration
Despite their low numbers, monarchs showed sure signs of migration this week:

People saw monarchs flying overhead, directly toward Mexico. This is called "directional flight." Dave Kust of Minnesota counted 14 monarchs per hour on September 1st while driving home from Iowa:

"The wind had finally shifted overnight to north. The monarchs I observed were flying south on these fresh cooler winds."

Most people only saw one or two nectaring monarchs last week, so an observation like this one was a welcome surprise.

"Had at least 30 adult monarchs nectaring in the native prairie pasture here late this afternoon. This is the highest number sighted by us this year. " Bruce Morrison, Hartley, Iowa 9/3/13

Four roosts have been reported so far, with a total of 530 butterflies. This graph compares roost data over three years, and illustrates this year's dramatic drop. These data suggest extremely low reproduction in the north. We'll be watching closely to see what happens further south. The number and size of roosts should increase substantially as the monarchs funnel toward Mexico.

Still Laying Eggs
According to observers, monarchs are still laying eggs as far north as Wisconsin and Michigan and as far south as Georgia and Texas. Historically, the U.S. corn belt has produced half of the monarchs that migrate to Mexico. How much will the fall-breeding southern monarchs contribute to this year's overwintering population? We really don't know.

  • Report sightings of monarch eggs and larvae.
Monarch Butterflies nectaring in Iowa prairie
Signs of Migration
Monarch Butterfly nectaring
Nectar is Critical
Monarch Butterfly overnight roost graph
Roost Numbers Down

Monarch Butterfly
Still Laying Eggs
Lori Piller
Monarch Population: Why the Decline?
Monarch numbers are down and people are wondering why. Examine the factors that caused the decline during the past year, and the downward trend over the past decade. Explore how you can help. Monarch Butterfly Population Graph
Tracking the Migration: Map and Journal
What to Report to Track Fall Migration Monarch Butterfly Migration Map: Peak Migration, Fall 2012 Worksheet: Journal Page
What to Report
Next Update September 12, 2013