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Migration Rate Math
Who saw the strongest migration this week?

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Week ending September 21, 2007
Here are a few of this week's observations. Read the comments and calculate the migration rate for each.
Record this fall's most impressive observations on your Record Sheet and add your favorites to your own Migration Highlights Map.

9/19/07 Asheville, NC (35.59 N, -82.56 W)
This evening from 5:30 to 7:30 pm, we counted roughly 300 monarchs sailing through Tunnel Gap on the Blue Ridge Parkway. It was roosting time for the ones in our view at 7:30pm; temp 64dF; winds stiff from the north.

9/19/07 St. Louis, MO (38.68 N, -90.38 W)
Since this past weekend's cold snap in the 40's over night, I counted 6 in a 10 minute time period all flying in a determined southwesterly direction.

9/19/07 Lake Ozark, MO (38.21 N, -92.66 W)
Today from 10AM to 4:30PM CST I observed 10 Monarchs all flying south at a height of 10-15ft. The temperature was in the upper 80's with a nice breeze of approx 10mph. These observations were on my school bus route.

9/16/07 Louisville, KY (38.25 N, -85.77 W)
Within one hour today we saw more than 20 monarchs flying through!

9/16/07 Columbia, MO (37.30 N, -89.62 W)
I observed 5 Monarchs in flight at a height of 15ft during an hour and a half period,. Temperatures were in the mid 80's with a light south wind (approximately. 5mph).

9/16/07 Kismet, NY (40.63 N, -73.34 W)
For about 2 hours while I was on the beach, looking in any direction there were butterflies visable, all heading west. At any one time I could see clearly ten butterflies sometimes more. Understand that there were many more visible but because there were so many in the distance you could not count them. I am sure there were hundreds,and possibly a few thousand butterflies that passed us as we sat at the beach.

9/13/07 Cape Girardeau, MO (38.95 N, -92.33 W)
Each day, during our 20 minute recess, my students look for Monarchs. We started this week with only seeing one or two a day. Now we are seeing 10 - 15 per day! It is very exciting!

9/14/07 Central City, PA (40.08 N, -78.73 W)
A heavy flight of monarchs today. We counted 115 in a ten minute time period. (Courtesy of the Allegheny Front Hawk Watch Site). For extra credit, make a graph of this fall's data. See how the migration rate changes from one day to the next:

  • Sept. 17: 2,000+ Monarchs (9.5 Observer Hours)
  • Sept. 14: Heavy flight of monarchs. Counted 115 in a ten minute time period. Conservative estimate over 2000 today.
  • Sept. 13: 650 Monarchs (9 Observer Hours)
  • Sept. 12: 245 Monarchs (8 Observer Hours)
  • Sept. 10: 175 Monarchs (7.5 Observer Hours)
  • Sept. 9: 90 Monarchs (6 Observer Hours)
  • Sept. 8: 95 Monarchs (8.5 Observer Hours)
  • Sept. 7: 87 Monarchs (8 Observer Hours)
  • Sept. 6: 152 Monarchs(8.5 Observer Hours)
  • Sept. 5: 420 Monarchs (8.5 Observer Hours)
  • Sept. 3: 400+ Monarchs (8 Observer Hours)
  • Sept. 2: 161 Monarchs (8 Observer Hours)
  • Sept. 1: 118 Monarchs (9 Observer Hours)

You can collect more observations like these from the sightings database and migration maps.