Monarch Migration News: October 29, 2015
By Elizabeth Howard
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First arrivals expected any moment at the monarch's winter home in Mexico.

With just 250 miles left to fly, monarchs rested by the thousands on Monday in Mexico's Sierra Madres.
Jose Ivan Cumpian Medellin    Juamave, Tamaulipas   October 26, 2015

News: Post-Hurricane Patricia
Hurricane Patricia threatened to intersect the migration last weekend, but the storm dissipated quickly and, in its wake, the monarchs moved in a strong pulse along northern Mexico's Sierra Madres.

"Peak migration is here. There are monarchs flying over my house right now! You can see them all over Ciudad Victoria, floating like bubbles in the sky."
— October 27, 2015  Ciudad Victoria, Tamaulipas

Only 80 Miles to Go
The southernmost roost report came from a town in central Mexico, only 80 miles north of the overwintering region.

"We have 40 monarchs roosting in our conifer tree. Normal arrival is around Halloween based on my 14 years of observation."
— October 25, 2015  San Miguel Allende, Guanajuato

Vacating the North
Note the dramatic drop in sightings reported from north of the Mexican border over the past 3 weeks.

October # Monarchs
7 - 13 150,000
14 - 20 15,000
21 - 27 2,000


Population Increase?
More roosts and larger concentrations this fall are raising hopes for a population increase from the record lows of the past 3 years. Scientists will measure the population in December; results are typically available by March.

  • Looking at the graph, how do you think this winter's population will compare to those in previous years?


Hurricane Patricia
Major Monarch Highway
Major Monarch Highway
Monarch Butterfly
Vacating the North
Monarch Butterfly
Population Increase?
Spotlight: Arrival and Mexican Traditions

The first monarchs traditionally reach their winter home in Mexico by the first of November, the Day of the Dead.

"The arrival of the monarchs symbolizes our ancestors' souls returning to Earth for their annual visit," says Estela Romero.

Monarch Butterfly Arrival in Mexico and Traditions

Maps: Report Your Sightings
What to Report to Track Fall Migration Monarch Butterfly: Adult Sighted Monarch Butterfly: Egg or Larva Sighted
What to Report Adult Butterflies
map | list | animation
Eggs and Larvae
map | list
Monarch Butterfly Migration Map: Fall Roosts, Fall 2015 Monarch Butterfly Migration Map: Peak Migration Fall 2015 How You Can Help
Fall Roosts
map | list | archives | animation
Peak Migration
map | list | animation
Journal and Activities
Next Update November 5, 2015