An Endless Parade

Silent Travelers

As monarchs traveled silently overhead, the voices below were anything but quiet: "This is one of the most amazing things I have ever seen!!!!" exclaimed Jim Worth of Savannah, Missouri as an estimated 10,000 butterflies crossed the sky.

"It started with many birds. I went to the house to grab my binoculars to attempt to identify a major bird migration.  I thought I was seeing leaves blowing through my binoculars. I was seeing literally thousands of monarchs riding the winds of a cold front moving through. The majority were gliding in the wind, expending little to no energy. Coming from the northeast to a southwest direction. It’s 5:00 p.m. and some seem to be coming to the ground as I write this..." (More)

Drifting Westward?

A remarkable flow into eastern Colorado has occurred over the last 10 days (Sep. 8-18). People reported hundreds of monarchs where there are typically only reports of single butterflies.

"They’re (1,000 monarchs) roosting in afternoon/evening on the north side of trees...Strong wind out of south." 9/15/18 Holyoke, Colorado (102° W)

The overwintering sites in Mexico are at longitude 100° W. Compare maps and notice the pathway monarchs have traveled during past years. Pay attention to 100° W and see how seldom they drift west of their destination.

Flight Behavior

What does monarch migration look like? Here's how observers described it this week:

"Northeast wind at 8 mph had monarchs gliding on the breeze heading southwest."

"The wind currents took them up very high until they disappeared from my view." 

"Flying high, on straight path, in short succession, approximately 1 minute apart."

"Riding the wind out of east northeast..."

 Energy Costs of Flight

A scientific study of monarch flight behavior revealed why monarchs would never make it to Mexico if they had to flap their wings all the way.