"After weeks of prevailing south winds, a mild cold front with light northerly winds has come through central Oklahoma. I saw approximately 200 southbound monarchs this evening between 5:45 and 7:00. They were at least 75-100 feet in altitude and appeared to be gliding effortlessly on their journey south. Here's wishing them fair skies, gentle winds and a safe journey."

— Patrick Bell  Edmund, OK  Sept. 29, 2015

Drifting Westward?
Two large roosts were reported from eastern Colorado, each containing hundreds of monarchs. Rarely are such large numbers reported from that state.

The overwintering sites in Mexico are at longitude 100°W. At longitude 103°W, the Colorado monarchs are west of their destination. (See map.) East winds during the past week seem to have carried a large number of butterflies westward of their usual pathway.

Energy Costs of Flight
Why is the wind such an important factor during migration? Glider pilot and scientist Dr. David Gibo discovered that soaring and gliding uses 25 times less fuel than flapping flight. Monarchs can save their precious fat reserves by using the wind.

Newsy Documentary: Saving the Migration
"We can't stay the course we're on or we will lose the migration," warns Dr. Chip Taylor.