A Puzzling Decline in Butterflies - San Francisco Chronicle 12/22/99

Paul Cherubini cherubini at mindspring.com
Wed Dec 29 21:07:20 EST 1999


While monarch butterfly counts along the west coast were low this past
fall, along the Atlantic coast it was a much different story: (data
below was copied from Dick Walton's web site)

CAPE MAY POINT,  ROAD CENSUS 1992-1999
(NEW JERSEY, USA)

The following table gives cumulative averages of monarchs observed per
hour at the end of each week in Sept and Oct. over the last 8 years:

Week 1992 1993 1994 1995 1996 1997 1998 1999

  1        8      12     96     43      9     184      3      23
  2      11      12   155     35      7     125    28      17
  3      12      41   143     29    52     156    21    106
  4      13      68   124     27    59     173    39    181
  5      12      82   129     27    73     153    51    463
  6      12      81   108     27    69     140    50    475
  7      13      72     95     29    66     129    54    409
  8      11      65     91     27    63     114    51    357

Totals:92   433   941   244  398   1174  297   2031

Clearly, the fall migration of 1999 along the Jersey coast was by
far the best observed in the past 8 years.

In my opinion, the data do not support the popular notion that
monarch numbers are being appreciably impacted by urban sprawl,
malathion spraying over New York City, roadside herbicide spraying,
genetically modified crops, logging in Mexico, commercial butterfly
releases, etc. etc. The cumulative impact (positive or negative) of
these human activites to date appears to be trivial.

Paul Cherubini. Placerville, CA


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