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

jimbetz at jimbetz.com jimbetz at jimbetz.com
Thu Nov 17 13:44:40 PST 2022


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

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

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