Monarch Butterfly Update: Feb. 10, 2011
Please Report
Your Sightings!

The monarch's winter habitat in Mexico is surprisingly cold. Temperatures can fall to freezing! This week, explore how the cool winter habitat meets the monarchs' needs for survival. Also, Estela Romero reports from Angangueo on the anniversary of last year's deadly landslides.

This Week's Update Includes:

 

Image of the Week

Monarch butterflies in sanctuary in Mexico

Risks and benefits?
Look for clues!

News: A Critical Time is Passing

It's almost mid-February. This mean the monarchs have now survived what's typically the coldest part of the overwintering season. "The really critical time for the monarchs is January and early February," says Dr. Lincoln Brower. Temperatures can fall so low the butterflies can freeze to death.

Dr. Brower has studied the monarch's overwintering biology in Mexico since the 1970s. "Right now we are waiting to hear how many monarch butterflies are overwintering in Mexico," says Brower. "World Wildlife Fund-Mexico usually releases their annual report in early January, after they have measured all the areas in December. These data are crucial to understanding the annual size of the eastern monarch population."

How large will this year's population be? Dr. Chip Taylor of Monarch Watch estimates 5-6 hectares. This graph shows measurements made over 16 years. Notice: Last year's population was the smallest ever recorded. This year's results are expected any day and will be provided here. What do you predict? Will the population be above or below average?


Graph of annual temperature in the monarch region

Average Low Temperatures

 

Graph of monarch butterfly population in Mexico.

How many monarchs in Mexico this winter?

Slideshow: Temperature and Survival

It can be warm during the day at the monarch's winter home in Mexico, but at night it's as cold as the inside of your refrigerator. This is surprising! Why do monarchs migrate long distances to overwinter in a place that is so cold? Explore this week's slideshow and resources:

  • Slideshow: Temperature and Survival
    Includes Photo Gallery, Booklet, Text-only Version, and Teacher's Guide with:
    • Pre-reading Anticipation Guide
    • Risks and Benefits Chart
    • Blank Book for Student Writing

 

Journal page

Slideshow
Temperature and Survival

Journal: Monitor Temperatures of Monarch Habitat

How Are Temperatures Affecting Monarchs Today? You can track real-time weather information at the monarch overwintering region in Mexico. Keep a journal of temperature conditions in Mexico and compare them to your own:

Weather in Mexico

Data Sheet Journal page for data analysis Sentence starters for data analysis: Gray whale migration data

Today's
Temperature

Record
Data

Analyze
Data
Sentence
Starters
Life in the Monarch Butterfly Sanctuary Region

Last Friday was the first anniversary of the deadly landslides that struck Angangueo on February 4, 2010. Estela Romero shares her town's experience as they mourned loss and celebrated survival.

"One year ago we suffered the worst tragedy in the history of our town ever imagined by any of us living here. We had a long religious ceremony and totally crowded procession remembering the children and adults who died one year ago and visiting the points in town most affected by the disaster. I hope the images give you at least an impression of what we lived today." 

 

Angangueo event mourning 1st anniversary of flooding and landslides

Monarchs were also part of this procession. Our Monarch was wearing a black and white ribbon on his upper right wing, in signal of grief, like the rest of the people.

Seeing Monarchs or Milkweed? Please Report Now!

All monarchs do not go to Mexico! Before spring migration begins, please help us document where monarchs are located this winter and where milkweed is available.

Map of monarch wintering sites in Mexico Pre-migration map: Winter monarch butterfly sightings (January or February) Map of milkweed emergence: Spring 2011

Mexico's Monarch Butterfly Wintering Region

Monarch Butterfly
Winter Sightings

(map/sightings/home)
First Milkweed
(map/animation/sightings)
The next Monarch Migration Update will be posted on February 17, 2011.