The discussion of the Backyard Bird Count comes at a time when I've been
mulling over the Christmas Bird Count (CBC).

Probably everyone who's tried to use the CBC numbers has wished that someone
in the last century would have added an unbiased count to the CBC numbers.
Because the CBC numbers vary so much with number of birders and access to
count areas, it's hard to extract any useful information from them beyond
the crudest comparison of species and numbers.

Various formulas have been used to try to compensate for number of
volunteers, with minimal success. The relationship between volunteer and
count is complicated. The difficulty of using CBC numbers is underscored by
contrast to the Breeding Bird Survey, which is one of the best sets of
long-term ecological data on population trends over a large area. The BBS
has a rigid sampling protocol and permanent routes.

I realize the CBC is as much education and public relations as it is data
collection. I wouldn't propose eliminating the count as it exists now or
changing any of the current CBC rules. I'd suggest instead the addition of
an unbiased count on Christmas morning in addition to the regular count.
(Christmas morning because traffic would be minimal across the country
then.) For example, a 15 mle. road transect running as close to a diagonal
as possible across the circle could be permanently established for each
circle and sampled by a pair of experienced birders using protocol similar
to the BBS (a stop every half mile, counting the number of birds seen for a
3 minute period within a quarter mile, etc.)

The CBC just began its second century. The next count would be a great time
to upgrade its methods.

Kelly Cassidy