[Tweeters] CBC trends in a warming world (Steve Hampton)

[jimbetz at jimbetz.com]

Steve/all,

   First let me preface this by saying that "yes, birds are moving further
North due to climate change".  I do -not- dispute that nor your research
(study).

   Having said the above ... it is somewhat misleading to use simple growth
percentages of birds seen and where.  Let me explain what I mean when I say
"somewhat misleading" ...

   Let's say that the number of Cedar Waxwings in the CBC goes up from 20
birds to 30 birds for Sequim.  On the surface that is a 50% increase and
I'm not disputing that number.
   But.  If that number isn't made in reference to the total population of
Cedar Waxwings in the CBC ... it can indicate a "larger trend" than what
experience shows.  As in ... just how often will any birder actually see
a Cedar Waxwing in the Sequim area in December?  When the total population
in that area - at that time - is so small.  Another way of saying this is
that the percentage is "anecdotal evidence" - it's true but it doesn't
tell the whole story.

   Again - I am NOT disputing the change(s).  I'm saying that the numbers
may not support the experience level we birders should expect.

   I looked at your 'article'.  I did not see the actual numbers there.
Did I miss them?  I'm asking was the 4.3% a result of 10s ... or 1000s
of Cedar Waxwings (or other birds) seen and reported during the CBC?

                                                     - Jim