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Monarch Butterfly Migration Update: February 28, 2003

Today's Report Includes:


Field Notes from Mexico by Dr. Bill Calvert
It’s the 4th week of February in Mexico and the dry season is in full throttle. The mountain trails are deep in fine dust, kicked up by horses and people traveling to see the butterflies.

At El Rosario, the monarchs decided not to cooperate this year. They didn’t form their colony within the loop of cement stairs which were provided for them and for the visitors. Instead, the colony is north of the Llano de Conejo. This choice by the butterflies requires the butterfly enthusiasts to walk about a mile to see them. At Chincua, the butterflies chose the often-used location in the Arroyo Hondo.

What is an "Ejido"?

The Chincua colony has now moved down-slope maybe 100-200 meters from its January location. In contrast, the Rosario colony did not appear to have moved at all last week, and has moved only a little this week. The difference in movement between the two colonies may be due to the location of water. It is likely that through the dry part of the butterflies’ overwintering tenure, the colony will always move in the direction of water.

Ironically, if the Rosario colony moves down the arroyo above which it’s now positioned, the butterflies will no longer be on ejido El Rosario’s land. Instead they’ll be on land owned by ejido La Salud. (Only edjio El Rosario now receives income from tourists.) Perhaps to avert this, the Rosario ejido is irrigating to provide water for the butterflies where they are presently located.

The most noticeable butterfly behavior seen during the past week was the striking behavior called “cascading,” in which literally tens of thousands of butterflies suddenly push off their perches, en masse, and fall downwards. After a fall of 3-5 meters they begin to fly, all in the same direction. The phenomena is absolutely awesome. Sometimes one cascade will trigger another, resulting in a sequential cascading from numerous branches in the colony. The cause and purpose of this spectacular behavior remains a mystery.

Until next week,
Bill Calvert


Unsolved Mysteries: Challenge Question #7
After years of observing cascading behavior, Dr. Calvert says the cause and purpose of the behavior remains a mystery. What experiment could you design to try to tease out the cause of cascading? Another question: Dr. Calvert says the presence of people might cause cascading. What do you think about this:

Challenge Question #7:
"Other than sound or sight, can you think of another way monarchs might be able to sense the presence of people?"

(To respond to this question, please follow the instructions below.)


Domestic Needs for Wood
Discussion of Challenge Question #5

Mrs. Swentzel's third grade class from Stanhope (Byram), NJ did a fantastic job discovering the many ways wood is used in the sanctuary area.

"We brainstormed as a class and came up with the following list before we saw the video: wood would be used to make chairs, tables, and other furniture, tools, utensils, bowls, firewood for heating and cooking, wood for making houses, canes, fencing, boxes, wagons, and carving.

"After watching the video we also added ladders, roofing (although we did say for building houses) outhouses, sheds for animals or barns, water trough and for harness for the cows. My students really enjoyed watching the video and were able to figure out a lot of what was being shown from the pictures."


Two Burrow-Loads Per Week

According to Ed Raskin of the Michoacan Reforestation Project, a typical family uses 2 burrow-loads of wood per week for firewood alone. One burrow carries a half a cubic meter of wood. This means that a typical family would use some 50 cubic meters of firewood per year. Multiplying this figure by the rural population in the region of 90,000, the equivalent of 40,000 mature oyamel fir trees is needed for firewood.

Reserve-Area Families Receive New Stoves
In response to this demand on the forest, conservation programs have aimed to reduce wood consumption by moving toward alternative stoves.

"It’s not as warm, but it is nice when my husband is feeling lazy about collecting wood," laughed Señora de Jesus about her new government-issued gas stove. "We can cook immediately, we don’t have to wait for the fire."

In Novermber, 2002, the governments of Michoacan and Mexico provided stoves to families who live in the immediate vicinity of the sanctuaries. While the stoves are efficient, the traditional wood stove is hard to give up. The kitchen stove is the only source of heat during the cold winter months at 10,000 feet altitude.

Concerned about the truckloads of wood they see coming down the mountain and passing their store, the Romero family in downtown Angangueo is also trying to cut back on their use of firewood by cooking with gas. "It’s cold, but we’re willing to make the sacrifice," says Estela Romero.

Laura Emila Romero cozy in bed, with her mother, Estela

Alternare Stoves Cut Wood Use by 50%
The Mexican conservation organization "Alternare" works with reserve communities to build energy efficient adobe stoves. Alternare estimates a 50% reduction in wood use with these stoves. In addition, much less indoor smoke is produced, an important health benefit to the family.


No Indoor Heat
Visiting American Family Found Angangueo COLD

Last year, teacher Dave Kust and his family traveled to Mexico with the monarchs during Dave’s sabbatical. They made it through the cold Anagangueo nights in an unheated home thanks to hot water bottles and piles of blankets on the beds. (Katie Kust slept under seven!)

"I quickly began to understand how important this microclimate was for the butteflies," said Dave.

Why No Heat?
Simply put, the cost of heat is too high because incomes in the area are so low. A good and safe gas heater, one that could heat a big room, costs $2,500 pesos. The gas to run the heater costs 25 pesos per day. Visitors to the region never fail to be amazed at the cold conditions under which people live. Temperatures inside the homes, day and night, remain in the 50's!


Can You Spot the Cause?
Challenge Question #8

In next week’s update, we'll discuss another significant cause of deforestation in the monarch region. Here's what it looks like:

Challenge Question #8:
"Can you name the cause of deforestation shown in these pictures?"

(To respond to this question, please follow the instructions below.)


Discussion of Challenge Question #6
Who Ate These Butterflies?
#1
#2
#3

Mrs. Nunnally's second grade class at Peter Woodbury School in Bedford, NH, looked at the pictures of butterflies.

“We think the predators were:
#1 black-headed grosbeak because the abdomen was gone
#2 black-backed oriole because the abdomen looked like it was split open
#3 black-eared mouse because only the butterfly wings were left
We also noticed that all the predators' names started with black!”


First Milkweed Emerging on the Migration Trail!
Exciting news was reported from Texas. The first milkweed of the season!

“Here’s a photo of early Asclepias viridis sprout from yesterday (2/23/03),” says Harlen Aschen. “The sanctuaries are only about 650 miles SSW of here and, with good southerly March winds, they could make it in less than a week. We will get serious about watching for very faded monarchs on a dedicated northbound course starting next weekend (3/1/03) but don't expect much for another week after that-- maybe the fifteenth of March.”


Before the Migration Begins...
  • Please report Over-wintering Monarchs now. We need your help before the monarchs arrive from Mexico.
  • Also, please report the FIRST MILKWEED Leaves to Emerge This Spring! We hope you will help us monitor the spring emergence of the monarch's food plant across North America.

How to Respond to Today's Challenge Questions:

IMPORTANT: Answer only ONE question in each e-mail message.

1. Address an e-mail message to: jn-challenge-monarch@learner.org
2. In the Subject Line of your message write: Challenge Question # 7 (or #8)
3. In the body of EACH message, give your answer to ONE of the questions above.

The Next Monarch Butterfly Migration Update Will Be Posted on March 7, 2003

 

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