This is fun: See where some of your CBC fee monies have been well spent.



Go to:



 www.birdsource.org <http://www.birdsource.org/>



Look left, click on the Christmas Bird Count box



Look left again, click "Historical Results", then scroll down



Select "Make a Graph" on the graph box (or find a map-that's fun, too).



Enter the species you want to search for in the "Type a name" box, "kestrel"
then click "Search"



Click on the words "American kestrel" in the search results box then click
"Add"



Select a date range-the last fifty years looks interesting.



Select Ohio or any other region you want to look at then click "Add"



Click "Make a graph"



Use the top graph, "Number / Party hr"



You can take it from here: Just follow the detailed instructions and you
will enjoy looking at graphs of numbers of birds of different species seen
over different time periods and different regions.



Now, make a map and try using the ten year animation for eruptive species,
etc. MORE FUN.



The kestrel decline in the late 80's and 90's may be 'real', but the data
reflects a short term trend well within the apparent variability over the
long term. The variability is due to many variables that can't be controlled
in the CBC model. Maybe the preceding kestrel increases during earlier
decades are related to increasing birding skills and CBC coverage and don't
reflect population trend? Visit your local statistician for guidance-the
details are over my head. There has been a lot of discussion about
statistical validity of CBC data. Use caution-see the bibliography.



Sometimes, if it walks like a duck, and quacks like a duck, it's probably a
duck.



Tom Bain

The Glaciated Allegheny Plateau

Chillicothe, Ross County




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