New Jersey Study Shows Slowest Fall Migration in 14 Years

For the 14th year, monarchs are being counted every single day as they migrate through Cape May, New Jersey. This October 1st, after four weeks of counting, the average number of monarchs seen per hour of observation is only 7.41 butterflies.

Here are the data that have been collected since 1992 as of Week #4 each year:


Monarchs per Hour
1992 12.95
1993 67.83
1994 123.57
1995 27.22
1996 58.99
Location of Cape May, NJ
Monarchs concentrate at the tips of peninsulas. They wait for northerly winds before crossing water.
1997 173.27
1998 38.95
1999 181.11
2000 37.90
2001 66.44
2002 45.48
2003 12.17
2004 7.41

Data courtesy of Dick Walton, Project Director, The Monarch Monitoring Project (Cape May Bird Observatory/New Jersey Audubon), Cape May, NJ.

Try This!

  • Make a chart of the migration rate each year. (Or print and analyze our chart above.)
  • Which year was the migration rate the highest? The lowest?
  • Write the years in order, from highest to lowest migration rate.
  • What is the average migration rate?
  • How does this year’s migration rate compare to the average?

National Math Standards

  • Understand numbers, ways of representing numbers, relationships among numbers, and number systems.
  • Create and use representations to organize, record, and communicate mathematical ideas.
  • Select and use appropriate statistical methods to analyze data.