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Monarch Butterfly Migration Update: October 4, 2001
Today's Report Includes:
- Highlights Along the Migration Trail
- The Value of Collecting Data Over Time
- Will My Monarch Make it to Mexico?
- Challenge Question #10
- How Far Fly in a Day? Discussion of Challenge Questions #6 & #7
- Other Monarch Flight Facts
Highlights From Along the Migration Trail
- Link to This Week's Migration Data (for classroom mapping).
The migration is only approaching its peak in Texas, and observers
there are in for a treat. A cold front is predicted to move across the state late tomorrow, and butterflies will
be streaming their way from points across the eastern continent. On the U.S. East Coast, the strongest migration
of the season was recorded last week at two monitoring sites. Observers everywhere seem to agree that numbers are
higher this fall than in recent memory. Here are some of this week?s highlights:
On Wednesday, October 1st, Texas?s Big Bend region was thick with monarchs heading south. ?I counted 3 a minute
around 9:00 a.m. and up to 12 a minute at noon around Del Rio,? observed Kathy Adams Clark while traveling from
Sanderson to Del Rio.
"While driving from Sonora to San Angelo (67 miles) I began to count the numerous monarchs crossing my path,?
reported Donna Kelly of South Elementary in Midland on September 29th. ?I was up to 68 when about 15 miles south
of San Angelo we encountered a virtual storm of butterflies. They were coming so fast and furious, I couldn't count
them all. I estimated 200 or 300. The encounter lasted about 2 miles and then the numbers thinned down again.?
?The principal at our school reported seeing about 20 Monarchs in their garden Sunday,? wrote William B. Travis
Elementary School in Pampa, Texas on September, 30th. ?Two girls in our school reported seeing about 30 Monarch
in the trees around their house this weekend.?
Meacham Middle School in Fort Worth, Texas reported on Friday, ?Today our 7th and 8th graders went outside around
2:45 to enjoy the mild weather and kick around the soccer ball. While outside, we saw 9 Monarchs over a 30 minute
period of time. They were flying alone and heading directly south. We are finishing up our symbolic migration,
so we were excited to see the real thing.?
Nearby at Parish Day School in Dallas, Ms. Stack wrote: ?One of my 4th grade students reports sighting approximately
25 monarchs in her Dallas backyard early Saturday morning.?
Oklahoma observers report more monarchs heading toward Texas. Thousands of monarchs were covering trees in a cow
pasture east of Pawnee, Oklahoma on Saturday, September 29. That evening, Buffalo High School teacher Anita Cosby
observed a large number of monarchs in the trees on her ranch while moving tractors to drill wheat. ?I saw them
just before sunset. I looked at a 10 inch section of a branch and counted 7 butterflies,? she said.
"They're here!? exclaimed Carole Jordan of Oak Park Magnet School in Laurel, Mississippi on the 30th. ?Driving
in town from 12:45 p.m. until around 2:45 p.m. I spotted approximately 1 every 5 minutes, flying in a definite
westerly direction, straight down streets or crossing avenues (our town is laid out in a traditional avenue north/south,
streets east/west).
Last Friday, September 28 a steady stream of monarchs was observed migrating south across the 24 mile causeway
bridge that connects the shores of Lake Pontchartrain near New Orleans. According to Joel Lyons, his colleague
counted 92 monarchs in the half hour trip. Later he tallied 142 monarchs in just 15 minutes! The migration continued
over the weekend. ?We drove across Lake Pontchartrain toward the east and couldn't even count the number of monarchs
we encountered,? said Louise Cragin. ?This is the most fabulous fall encounter that we can remember, and we have
been watching for years,?
Meanwhile, Ms. Moon's class of Pickens Elementary in Pickens, South Carolina has been monitoring the migration
there: ?Each day at recess we have seen a stream of Monarchs flying over the school. Our recess lasts only 20 minutes
and takes place at noon. We count about 15 each day,? she says.
In the aftermath of the September 11th terrorist attack, Regina McCarthy of Gateway Environmental Study Center
in Brooklyn, New York has found brief solace as monarchs visit their urban garden. ?Things are slowly getting back
to near normal here in NYC. In the end it has been a season of hope for all of us in the face of terrible sadness.
People have been wonderful to us.? She sent these photos of the Gateway garden on October 3rd. ?It?s hard to really
get the full impact of literally what seems to be close to one hundred monarchs on the bushes today.?
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In New Jersey, "a large wave of monarchs moved into the Cape May area on Friday, September
28th," reports Dick Walton, director of the Cape May Monarch Census. "We recorded our highest census
run count for the season, and over 10,000 monarchs were counted in local roosts.?
To his south, Denise Gibbs of Virginia?s Chincoteague Monarch Monitoring Project also reports the season?s strongest
migration at her monitoring site. An average of 880 monarchs per hour were streaming through on September 29th!
The Value of Collecting Data Over Time
Imagine counting the stream of butterflies passing over your head each day during the entire fall season! Daily observations at monitoring sites such as Cape May and Chincoteague (say ?chink-o-teeg?) are providing a new view of migration. Now in their 10th and 5th years respectively, these annual migration counts are providing a long-term record of migration patterns. Both sites are migration hotspots because they?re located at the tip of a peninsula. The monarchs congregate there in high numbers to avoid the over-water crossing until the wind is right.
Are there truly more monarchs this year than last? What time of year is the migration strongest in a particular place? What can you learn from this migration data?
Try This!
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Sample Graph of Cape May Migration Data |
2) Does the migration appear to peak each year during any particular week?
3) List the years in order, from the strongest to weakest migration seasons.
4) To date, in which year was the monarch migration through Chincoteague the strongest?
5) In which year were the fewest monarchs seen?
6) Do you think the Chincoteague migration data is an accurate tool for comparing monarch numbers from year to year? What factors might affect the counts, so that the monarch population might seem higher or lower than it actually is?
Will My Monarch Make it to Mexico?
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Tagged by Mrs. Kloewer's Class in York, Nebraska |
Challenge Question #10:
?Of the tagged monarchs that were recovered Mexico, what?s the latest date one was tagged??
(To
respond to this question, please follow the instructions below.)
How Far Fly in a Day?
Discussion of Challenge Questions #6 & #7
As discussed in our September 20th report, one tagged monarch was recovered one day later 140 miles from its tagging site! Challenge Question #6 asked, "In how FEW hours might the monarch have traveled the 140 miles?? As a follow-up, Challenge Question #7 asked, "Using the number of hours you calculated for Challenge Question #6, how many miles per hour might the monarch have traveled, on average?"
- Since monarchs don?t fly in the dark we counted the daylight hours between sunset on Oct.
6th (6:35 pm) and sunrise on the 7th (7:01 am).
- Then, because monarchs don't fly when it?s too cold, we took away 1.5 hours before sunset and 1.5 hours after sunrise. (Since we don't know the actual temperatures those days, this is just a an estimate. Observers say monarchs arrive before sunset and leave after sunrise, when they are warm enough.)
Thus, here are the hours we estimate the monarchs could have flown:
|
Date |
Time Started |
Time Stopped |
Elapsed Time |
|
Oct. 6 |
1:00 PM |
5:05 PM |
4 hours, 5 minutes |
|
Oct. 7 |
8:31 AM |
4:56 PM |
8 hours, 25 minutes |
|
TOTAL |
12 hours, 30 minutes |
Dividing 140 miles by 12.5 hours = 11.2 miles per hour.
In summary, the monarch may have flown for as few as 12.5 hours and traveled
an average of 11.2 miles per hour.
Other Monarch Flight Facts
Nobody knows how fast monarchs migrate for certain, but here are other observations to keep in mind:
- The record flight is 265 miles of a monarch that was tagged one day and recaptured the
next day. This monarch was tagged during the Urquhart tagging program. It flew from its tagging site in Waterford,
Pennsylvania to a site in Virginia.
- Dr. Calvert says the monarchs? daily progress is determined largely by the direction and
strength of the winds. Strong frontal systems tend to "bunch" them up into discreet pulses. Then, when
the winds are northerly and strong, the monarchs may fly as much as 400 miles in a day.
- Denise Gibbs has observed an interesting pattern of travel between the East Coast monitoring sites: ?Dick Walton would report big ?waves? of monarchs coming through Cape May, New Jersey about 150 miles to our north. It would take 2 days for these waves to reach me at Chincoteague National Wildlife Refuge (suggesting 75 miles/day). I would report big waves to Mark Garland at Kiptopeke, VA which is about 70 miles south of me. He would receive them one day later (suggesting 70 miles/day). This was not a one-time event. It happened time after time over 3 seasons. Usually, but not always, the winds were from the north, northwest, or west-northwest with full sun.?
Notice that Denise's predicted pattern occurred last week, on September 28th and 29th!
How to Respond to Today's Challenge Question:
1. Address an e-mail message to: jn-challenge-monarch@learner.org
2. In the Subject Line of your message write: Challenge Question #10.
3. In the body of the message, answer the question above.
The Next Monarch Migration Update Will Be Posted on October 11, 2001.
Copyright 2001 Journey North. All Rights Reserved.
Please send all questions, comments, and suggestions to our feedback form
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