|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.