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Monarch Migration Update: October 11, 2000

Today's Report Includes:

Highlights Along the Migration Trail

Monarchs and Space Shuttle Grounded by Same Gusty Winds
The cold, arctic air mass that moved across the continent during the past week brought record low temperatures across the monarch migration trail. The system's steep pressure gradients caused high winds in many regions.

NASA forecasters were concerned about the effect of gusty winds on the Space Shuttle Discovery, so they delayed the launch. Imagine how these winds might affect the travels of migrating butterflies! On Monday, with 20 mph winds and gusts up to 30 mph on the Virginia Coast, Denise Gibbs saw the devastating effect first-hand:

10/09/00 Assateague Island, VA
(Click on image to enlarge)
"The 10am census showed 900 Monarchs per hour migrating (being blown) through--the largest wave of Monarchs here so far this migration season. I stood on the beach dressed in 2 layers of hooded polartec with windblock topped with an Eider-down jacket. My face, (the only exposed skin on my body) felt raw from the sandblasting wind.

"I watched helplessly as Monarchs rolled and tumbled past me like tiny orange tumbleweeds on the sand. Normally on this island Monarchs favor north or northwest winds for migration, but today the north wind's fury is forcing them down to the ground. If they're lucky enough to land on vegetation--dune grasses or Seaside Goldenrod, they cling to the leeward side, staying 3-5 minutes to rest and warm their flight muscles in the sun. Others, not so lucky are landing on the exposed sand and are trying to get a foothold on the loose, blowing grains of sand. Monarchs that lose their grip are getting blown out to sea.

"I can only guess at the fate of this 'wave' of Monarchs. But I can tell you what happened on a similar October day in 1999 here. Winds were from the west at 30mph. I watched Monarchs by the thousands getting blown out to sea all afternoon until the winds ceased at 5pm. The next day, the high tide deposited thousands of Monarchs on the beach. All had wings saturated with salt water, but most were still alive. Families on the beach assisted in scooping up wet Monarchs, placing them on higher, dry ground, blowing on their wings until they dried and releasing them to more favorable winds."
Denise Gibbs, Chincoteague Monarch Monitoring Project (

Migration Frozen in Place in Texas and Coahuila
Teacher Harlen Aschen reports from the Texas Gulf Coast: "The record low for tomorrow (Thuesday) morning is 43 dF. Somewhere there are a bunch of cold, wet monarchs. The drizzle, light rain, and cold seem to stretch along Interstate 10 and to South Texas. The late hummingbirds are stacking up at the feeders and are having a hard time coping with the cold ... a report of some appearing dead or having "fainted" ... (torpor?). Is this same word used when the monarchs get extremely cold?"

Dr. Bill Calvert reports from his vantage point in Texas: "Basically everything has been frozen in place by this enormous cold wave that's come down and caused all this rain. I can't say it's broken the drought, because it's only rained about 1 to 1.5 inches. Most monarchs seem to be in the western part of the flyway, west of Rocksprings, Ballinger, and Junction to the Midland area. When things clear, monarchs should fill the skies."

Migracion en Coahuila
"El cuarto frente frio de esta temporada invernal y las lluvias que nos trajo el huracan Keith han tenido a todo el estado de Coahuila, Nuevo Leon y Tamaulipas con mucha lluvia, neblina y temperaturas muy bajas para ser el mes de octubre. En Saltillo tenemos tres dias a cero grados. Las mariposas no han volado y he recibido reportes de Acuna, Piedras Negras y Monclova de que las mariposas estan perchadas formando racimos de 50 a 100 monarcas. Espero que cuando mejore el tiempo, las veamos seguir su viaje de nuevo y que este fenomeno meterologico que no se presentaba desde hace seis anos no haya causado muchas bajas."
Saludos desde Coahuila
Rocio Trevino, Correo Real (

How Do Other Butterflies Survive the Cold? Discussion of Challenge Question #8
Speaking of cold temperatures, let's go back to look at how other butterflies and moths manage to survive the winter, without migrating southward to escape freezing temperatures. Challenge Question #8 asked, "In what stage of their life cycle do these butterflies and moths over-winter?"

1. Viceroy

2. Black Swallowtail

3. Sphinx Moth

"Dear Journey North," wrote the 2nd grade students at Haddonfield Friends School. "We think that we know the answer to the Challenge question #8. The Viceroy Butterfly larva hibernates in rolled leaves for the winter. The Eastern Black Swallowtail winters over in its chrysalis. The Sphinx Moth hibernates in the pupa stage under the soil."
Teacher Bonnie's Second Grade Class, Haddonfield Friends School, Haddonfield, NJ

News From Students at Sanctuaries in Mexico
Students at 6 different schools surrounding the sanctuaries are watching and waiting to announce the monarchs' arrival. Every week, Pedro Ascencio school is monitoring the temperature, so you can see what the weather is like there. As you know, monarchs migrate to escape the cold, northern winters. So before reading the Challenge Question below, discuss as a class how you imagine the weather in Mexico to be. Guess the high and low temperatures on a typical fall day.

Measurements Are Metric in Mexico: Challenge Question #11
Now here is your challenge. The metric system is used in Mexico, so the students from Pedro Ascencio school sent these temperatures in degrees Celsius.





21.4 C

7.9 C


24.9 C

5.5 C


26.5 C

1.5 C

Challenge Question #11
"What were the high and low temperatures on the following days, in degrees Fahrenheit? How do these temperatures compare to those that you guessed?"

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

How to Respond to Today's Monarch Challenge Questions:

IMPORTANT: Please answer ONLY ONE question in each e-mail message!

1. Address an e-mail message to:
2. In the Subject Line of each message write: Challenge Question #11 (or #12)
3. In the body of the message, answer ONE of the questions above.

The Next Monarch Migration Update Will Be Posted on October 18, 2000.

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