Hello list,

Since this thread began with an early CBC but shifted to a discussion on
RHWP, I thought I would add some more recent CBC data in the form of a
graph. The graph shows CBC 60 years worth of Ohio CBC data from 1951 to
2010.  The data was created from data obtained from the National Audubon
Society's CBC site.

Regrettably, for this discussion,party-hours before 1950 were not well
tracked and thus are not reliable. Likewise the raw numbers of any species
is not reliable as there was/was not more birds but definitely fewer counts
and counters.

As to the graph, the vertical axis is birds per party-hour (determined by
dividing the total (state-wide) number of birds by the total number of
party-hours of those counts where birds were seen. For example. the 0.2
line really means one whole bird was seen every 5 hours on average.

The horizontal axis is obviously years.  The trendline Poly[nominal]-5 is a
fifth form polynomial as per the formula in Microsoft EXCEL 2003. The
Moving Ave - 3 is computed as being the average of the graphed year and the
2 previous years.e.g. average of 1973, 1974 and 1975 for the year 1975 on
the graph.  Also note that for the poly trendline, the first and most
recent curves are exaggerated downward due to the nature of the formula.

That being said, note the drastic downward trend for whatever reason during
the 1960's.

To add to Bill's observations, one could speculate  (but not verify) that
another agricultural practice contributed to the habitat loss including
food supply. During the 1960's and 70's the predominance and increased
number of multi-headed, self-propelled corn combines (rather than pulled
few-headed corn ear pickers) which more efficiently removed the grain from
the fields was possibly a mitigating factor in the bird's food supply.
Farmers, to make these large machines more economical, also expanded field
sizes which in the process decimated any field edges and woodlots.

It would be interesting to compare Ohio's RHWP numbers with non-cornbelt
states.

To add to Milt Trautman's early 20th century observation of road kills
(redheaded woodpeckers are almost addicted to corn spilled along highways)
was the 1950's and 1960's increases of traffic speed limits on all types of
roads throughout the state. For a corn-eating bird, gleaning the grain
along a road when vehicles are going 30 mph is a dangerous habit. At 60 mph
it is suicidal.

  Also note that the numbers are somewhat cyclic over a 2 to 4 year period.

Roger Troutman
Mansfield Ohio

 [image: Inline image 1]



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