|
| Please
Report Your Sightings! |
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This week's word is survival. The strong spirit of the people of Angangueo survives as they pick up the pieces of their lives, literally and figuratively. Monarch butterflies migrate to Mexico to survive. So what happens to the butterflies when a strong storm and below-freezing temperatures strike their winter refuge?
This Week's Update Includes:
- News: Butterflies After the Storm
- Slideshow & Guide: Temperature and Survival
- Journal: Think by Analogy
- Seeing Monarchs or Milkweed? Report Now
- Research Question and Links: Explore!
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| President of Mexico Visits Angangueo |
Signs
of Survival!
How did the rainstorm that hit Mexico two weeks ago affect the monarch
butterflies overwintering there? Early reports from tourists visiting
the colonies are promising. Clearly, thousands upon thousands of beautiful
butterflies survived the storm as you can read in Kim Baily's observations
in the Chincua and Pelon monarch sanctuaries:
Although these signs are promising, a scientific assessment of the complete region has not yet been done. Scientists are watching with concern because the weather conditions were a recipe for disaster: wet butterflies and below-freezing temperatures.
“The worst possible scenario for the monarchs is for them to get wet, and then for the temperature to drop when the sky clears,” says Dr. Lincoln Brower. "The key will be to see how cold it got after the rain. We will know soon when we examine our Weatherhawk data from the Chincua sanctuary."
Exactly
How Cold Can a Butterfly Be?
From studies after a previous winter storm, Dr. Brower learned how critical
each degree below freezing can be for wet butterflies. Here are the temperatures:
| Wet
Butterflies |
|
How
Cold? |
How
Bad? |
-3°C |
5%
killed |
-4°C |
40%
killed |
-5°C |
80%
killed |
Dead
or Alive?
Dr. Brower says visual observations in a colony can be deceiving. Monarchs
that appear to be clustering might not actually be alive. He shared this
gruesome observation: it's actually possible for dead butterflies to remain
in their clusters. Here's why: monarchs hang in their clusters effortlessly
because of special claws on their feet. (The cold temperatures the butterflies
regularly experience during the winter paralyze them.) After a previous
storm, Dr. Brower witnessed clusters of dead butterflies falling to the
ground many days after they had been killed by the cold. To learn more
about how monarchs hang on when they're cold see:
An
Important Year to Survive
This winter's population was at a 16-year low based on measurments
made in December. How many monarchs will survive the winter and migrate
north in the spring? That is the important question on everybody's mind.
Let's hope mortality from the February storm was minimal!
How
many monarchs now?
The
monarch population was at an all-time low before the February storm.
| Rain
in the dry season? |
|
It's
unusual to have a substantial rainstorm in Mexico during the dry
season. Look at Mexico's normal precipitation patterns in this animation.
|
Why do monarchs migrate long distances to spend the winter in a place that is so cold? What are the risks and benefits of Mexico's cold climate? This booklet and slideshow explore the relationships between temperature and monarch survival. The accompanying Teacher Guide includes activities, handouts, and a template for students to write their own fact book.
Temperature and Survival:
How
Does the Forest Protect the Monarchs?
Dr.
Lincoln Brower says the monarch's forest is like an umbrella and a blanket.
Analogies help us understand new things because they draw upon our past
experiences. This journal page has students use analogies to describe
how the forest protects monarch butterflies.
- Think by Analogy: How does the forest protect monarch butterflies?
Journal
Page
Think by Analogy
All monarchs do not go to Mexico! Please help us document where monarchs are located this winter, and whether milkweed is available.
This
Week's Research Question:
What adaptations do monarchs have to survive in cold temperatures in Mexico?
Explore these links to do your research:
- Why do monarchs form colonies?
- Why don't cold butterflies fall?
- Why do monarchs shiver?
- Camouflage in the Overwintering Colonies
Additional links to explore:
- Journal Cover & Pages: Monarch Winter Habitat Journal
- Overview: About Journey North's Monarch Butterfly Overwintering Study
- Get Ready to Track Spring Migration: How to Watch for Monarchs
The Next Monarch Migration Update Will Be Posted on February 25, 2010.
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