numbers game or counting

[Martin Bailey]

----- Original Message -----
From: "Michael Gochfeld" <gochfeld at EOHSI.RUTGERS.EDU>
To: "Barb Beck" <barb at birdnut.obtuse.com>
Cc: "leps-talk" <TILS-leps-talk at yahoogroups.com>; <leps-l at lists.yale.edu>
Sent: Tuesday, April 30, 2002 7:45 AM
Subject: numbers game or counting


> I agree too, that butterfly numbers are more variable than birds due to
> phenology and weather conditions and events the previous week, month or
year.
>
> Also individual counters may have particular preferences and spend more
time
> hunting for particular species or bothering to count the common ones. For
> example, there are a lot more Cabbage Whites (at least in NJ) when you
actually
> count them individually, than if you just do drive by estimates.  That
must be
> more of a problem for less conspicuous species.

House Sparrows are notoriously undercounted on Christmas Bird Counts because
folks rather spend their time on looking for the "more interesting" species.
Except in one location.  There the count co-ordinator insists that great
effort is spend on counting House Sparrows.  He is very proud that "his"
count has more House Sparrows recorded on it than anywhere else.

I don't think this changes anything.  What matters is to keep track of the
ebb and flow of a species over time.  In the case of the "perfect" count the
order of magnitude for House Sparrows will be higher than in the "fun"
counts.  The trend line will be the same for both over time.

In the case of counting butterflies annual fixed day counting may be great
for getting folks and becoming aware of what is around them.  Otherwise,
there is a need to go back to the drawing board.

My suggestion: Note first sighting in a season and count total numbers of a
species seen on each subsequent sighting.  Note last sighting.

Do I do this?  No.  My interests lie elsewhere. (I do keep
first and last sighting records for all species.)

Martin Bailey




 
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