"counting" butterflies (was: Tucson sightings)

[Eric or Pat Metzler]

The Pollard method, mentioned by Doug Yanega, is relatively easy to
understand, and easy to explain to others.  The Ohio Lepidopterists society
is now in its third year of doing Pollard counts statewide.  We have about
30 monitoring sites and about 60 persons who regularly count butterflies in
parks, natural areas, and other places.  The system is a wonderful way to
get persons involved with butterflies - the same people can do something
useful while they are watching butterflies.  As Doug said, the consistency
of the method and the counts is important.

The Ohio Lepidopterists wrote its own counting manual to augment the
program.  You can see the manual by visiting The Ohio Lepidopterists'
butterfly monitoring web page
http://www.dnr.state.oh.us/odnr/wildlife/diversity/lepid/default.htm     You
can download the manual, or you can send $2.00 to me and I'll send you a
copy of the manual.  It is free - the $2.00 is for postage and packaging.

Be sure to check out the rest of the Ohio Lepidopterists' Butterfly
Monitoring website where you are there.  Comments are always welcome.

The next Butterfly Monitoring Workshop will be 24 March 2001 in Toledo Ohio.
You are all invited.  Preregistration is required if you want to eat the
included lunch.

Cheers from a snowy (today at least) Columbus Ohio.

Eric Metzler

1241 Kildale Sq. N.
Columbus Ohio 43229

"Doug Yanega" <dyanega at pop.ucr.edu> wrote in message
news:b6ba1117090210042312@[138.23.134.119]...
> >Ron and others,
> >
> >I can fully understand and I respect the concern regarding the accuracy
of
> >"counts".  I will, however, attempt to explain and defend "counts" a
little
> >in order to try and show that they may not be as ridiculous as they seem.
>
> I'll add to this by pointing out that certain types of counts are more
> useful than others. There's a textbook about a well-known British
Butterfly
> Monitoring project (probably still ongoing), that uses a much more
sensible
> system; each monitor walks the same exact personal route during the same
> time window each year, under similar conditions. Results from any given
> monitor are ONLY compared directly to results from that same monitor in
> different years, and standardized before any comparisons *between*
monitors
> are made, because they assume (correctly) that no two observers are
exactly
> equally proficient. In other words, if monitor X is poor at spotting
> skippers, and monitor Y brilliant at it, then X's reports will always be
> lower than Y's even if the actual abundance at their respective sites is
> the same; but by *standardizing* and using percentages rather than raw
> numbers, one can say "there was a 30% increase in skipper sightings by
both
> monitors X and Y in 1998 versus 1997 and 1999" and feel better about it
> being a real pattern.
> Systems like the US butterfly counts and the famous Breeding Bird Survey
> assume that all observers are equally proficient, and this severely
> undermines the validity of the comparisons.
>
> Peace,
>
>
> Doug Yanega        Dept. of Entomology         Entomology Research Museum
> Univ. of California - Riverside, Riverside, CA 92521
> phone: (909) 787-4315 (standard disclaimer: opinions are mine, not UCR's)
>            http://entmuseum9.ucr.edu/staff/yanega.html
>   "There are some enterprises in which a careful disorderliness
>         is the true method" - Herman Melville, Moby Dick, Chap. 82
>
>
>
>
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