Wood Nymphs: banner year??

[Chris J. Durden]

I agree that the 15 mile count circle on one day a year leaves much to be
desired as a tool for faunistic study. I think for most people it is a
teaching/learning occasion rather than a research tool. Here in Austin TX
the Austin Butterfly Forum (a NABA affiliate) held a count on the first
Saturday after July 4th. Three parties observed different localities within
the count circle between 8:30 AM and 12 noon. I went with one of the
parties teaching, rather than counting. I think the whole process was very
worthwhile.
  In order to obtain numbers for my Nineteenth Austin Urban July Butterfly
Count I conducted another count on the traditional first Saturday after
July 10th. This was a day when the high was 107 dF and we have been weeks
without rain. I was the only one who showed up. The traditional site on
Lower Barton Creek had no butterflies recorded. Count was from 10 AM to
5:30 PM. I feel I can compare the numbers from these counts over the last
19 years all taken between day 190 and day 199. They show nicely the slow
recovery of our fauna following a general crash when the imported fire ant
was introduced. This time is for our butterflies analogous to the Christmas
count for birds. The butterflies are at a low point in their populations
between the April-May peak and the September-October peak.
  I can make raw data and summaries of the 19 years of Austin Urban July
Butterfly Counts, available to anyone interested.
........Chris 


At 07:11  17/07/00 -0400, you wrote:
>John Acorn's comments on Wood Nymphs is exactly the reason why I think that a
>one day, 15 mile count circle is an inappropriate way to census
butterflies or
>document trends. It was borrowed uncritically from winter birds (where it
>probably isn't all that appropriate either), based on a method selected
nearly a
>hundred years ago.  Sort of like pulling apart the human genome with a
pair of
>pliers.
>
>The phenology of a season and the weather on a single day can seriously
distort
>counts. For example, the Raritan Canal count of Monarchs in 1999 was an
all-time
>low, yet fall migration was an all time high.
>
>What may be interesting is to look at the variability of some common species
>across the parties on a given count.  We had a few species yesterday (Raritan
>4JC) where all four parties got the same number per hour plus or minus a few,
>indicating a rather uniform distribution (swallowtails, Pearl Crescents, for
>example), and others which shoiuld have been uniform (i.e. Common Wood
Nymphs)
>which were virtually absent from all but one habitat.
>
>Mike Gochfeld
>