gochfeld at eohsi.rutgers.edu
Tue Jul 15 20:34:58 EDT 2003
My 4JC Ambivalence #2. Recent postings on one or both lists have both
criticized and supported the value of the Fourth of July counts (4JC).
When the 4JCs were started by the Xerces Society people (not NABA) back
in the mid-1970s, the 15 mile diameter circle was adopted straight out
of ornithology, with little regard (in my view) for the differences
between how we find butterflies and birds (spatial scale). However, a
number of counts made no pretense of covering such a large circle with a
3 mile circle specified in one case (and a single backyard with a single
species, guess which?) in another case.
It may have made sense in terms of the area that a large number of
people could comfortably cover in a day. And it may make sense in areas
of the country where there is a lot of homogeneous habitat so that you
dont need to cover the whole circle to find out whats in the whole
In reality, most counts dont sample the entire circle, but an outsider
wouldnt know that. Count circles may be gerrymandered to include prime
About 15 years ago, I recommended that the 4JCs (or equivalent) focus on
much smaller management units----a park, a forest, a preserve, even a
town----and get to know the fauna (and flora) in more detail. This
suggestion was not take seriously.
My main reasons for not liking the 4JCs
1) We encounter butterflies at very close range (usually within a few
meters, perhaps even a net-handle length). We encounter birds at
distances of dozens to hundreds of meters, and we can even scope out
ducks on a river at over a kilometer.
2) Butterfly phenology is such that even a bivoltine species can be
completely non-flying on the day of the count (not absent of course
since the early life stages are hiding out). Our 4JC at Vischer Ferry,
NY, covers the habitat of the endangered Karner Blue (L. melissa), but
more often than not we are between broods. The editor of the first
count noted that the 4th of July was generally not optimal and dates
would have to be changed.
3) There is a lot of un-tapped information. Counters may note what
nectar sources are present, but there is no recording scheme for which
nectar sources are actually used by butterflies on the day of the count.
My main reasons for liking the 4JCs (apart from the fun of being in the
field for a day), is that we try to cover the same area year after year,
and even relatively new counts already have ten years of data.
Patterns emerging across counts may be more valuable than temporal
trends within counts.
Subsequent posts will examine the limitations (and strengths) of such
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