Wood Nymphs: banner year??

[Michael Gochfeld]

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

John Acorn wrote:

> Hi Folks,
>
> This year, there were no Wood Nymphs (Cercyonis pegala) on the Edmonton
> count either.  This, however, has nothing to do with whether they are having
> a good year.  The weather was cool this spring, so this species was not yet
> on the wing when we did the count.  Season plays a huge role here in Canada,
> and it is very difficult to compare one year's count with another unless you
> know for sure that they represent the same portion of the phenological
> progression.
>
> John Acorn
> Edmonton