Subject: CBC's
Date: Jan 3 16:49:53 1995
From: "Michelsen, Teresa" - TEMI461 at ecy.wa.gov



Dennis - Too bad your message didn't go out BEFORE the CBCs - I think it
should be required reading for bird count volunteers. While it has been
interesting to read about the rare bird species that have been seen in
various counts, I have been wondering what larger trends might have been
noticed - very few people commented on those. I had assumed that they just
weren't done compiling the data yet, but maybe that's not the case. Where
DO these data go? Is there a central repository somewhere?

Listers vs. counters aside, I wonder about the effects of weather on bird
counts. I have been participating in the WDFW Winter bird survey and doing
a less formal weekly survey of my own property and find that the weather
seems to have a large effect on the birds I might see in any given day, with
the birds definitely more visible on sunny days than in periods of rain. I
have concluded, watching my own yard, that there are not any less birds,
they are just hiding out and not visible for counting. Given the great
extremes of weather we experienced over this last bird count period, I
wonder how comparable the earlier counts done in cold, driving rain are to
those done this past weekend when it was sunny. Can these data sets really
be combined or compared? Does anyone keep track of weather conditions and
look at how it affects the counts from year to year (or place to place)?
For the DFW surveys, they have you count two days in a row and take the
higher of the two counts for each species. This may be an attempt to deal
with the vagaries of the "snapshot" you get when counting on a given day.
On the other hand, it's obvious that logistically, the CBCs couldn't last
two days in a row, and even that might not solve the weather problem. I was
surprised (this is my first counting season) that everyone didn't have to
count on the same day, under the same conditions.

Teresa Michelsen
temi461 at ecy.wa.gov