[TN-Bird] reflections on finding redstarts during atlas and foray efforts
- From: "Stephen Stedman" <SStedman@xxxxxxxxxx>
- To: "tn bird" <tn-bird@xxxxxxxxxxxxx>
- Date: Thu, 19 Aug 2010 16:07:13 -0500
About a quarter century ago, I recall hearing a Tennessee birder claim
that with proper diligence one could find Bachman's Sparrows in every
Tennessee county. This claim seemed somewhat exaggerated to me at the
time, and the fact that I have found only one Bachman's Sparrow in one
Tennessee county during the intervening years has not caused me to think
it any less exaggerated.
That anecdote notwithstanding, I have always thought that there were
more breeding American Redstarts (AMREs; pronounced am-ree) in Tennessee
than were turned up by the breeding bird atlas effort; there might even
be breeding AMREs in every Tennessee county, if only we took the time to
seek them. [Here I must mention the exhaustive recent effort to find
them in Lewis County by Bill Pulliam, an effort that apparently failed;
here I suppose is an exception to test the rule I propose.]
The Tennessee breeding bird atlas reveals the AMRE to be mostly thinly
distributed in maybe 50 counties, leaving 40+ counties with nary an AMRE
recorded during the atlas, which, if you will recall, focused attention
on 700+ priority blocks rather than all 4200+ blocks in the state.
Given the work-force available in 1986, even tackling 700+ blocks was a
huge undertaking, and it is a credit to those who contributed to this
effort that it came to fruition. As it turned out, nearly all 700
priority blocks were surveyed and another 1800 blocks got at least some
attention paid to them, leaving only 1700 blocks that received no survey
effort at all.
For most species of birds, the atlas method of focusing on priority
blocks with attention to additional blocks as resources were available
was a good one. I think most maps in the atlas book are good
representations of the distribution of the breeding avifauna during the
late 1980s and early 1990s.
But the AMRE is not one of them; at least I would like to make the case,
with some limited data, that the AMRE is a species whose true
distribution in the state we will never know if we do not organize a
project to survey all 4200 blocks in the state. [Oh dream on!]
Here's why I make this claim. The atlas map for AMRE shows no AMREs in
Cumberland, Pickett, and Clay counties, and it shows only two possible
blocks where AMRE might have been in White County, each a block that
overlaps two counties, so unless the observer happened to know in which
county the AMREs were found in the overlapping block, it might or might
not have been present in White County.
For the past four years, forays have been conducted in Upper Cumberland
Region counties, including Cumberland, Pickett, Clay, and White. Each
foray in those counties has turned up one or more sites with breeding
AMREs. In one block (Grassy Cove 3) in Cumberland County, for example,
18 singing males were found. It's possible that all these AMREs moved
in since the time of the atlas; I can't prove otherwise, but I doubt
that a block with 18 AMREs now was devoid of them 20 years ago,
especially when the habitat has not changed too much, in that time. [I
suppose I should at this point also consider the possibility that
climate change has brought in all these breeding AMREs over the past 20
years, but let's not go there.]
Another piece of evidence comes from a county just to the north of
Tennessee, namely Pulaski County, Kentucky, where the Kentucky atlas
project turned up not one AMRE in the 12 priority blocks found in the
county (this atlas project , too, used the formula of surveying one out
of every six blocks). A foray effort in Pulaski County this past June
turned up AMREs in 12 of the county's 72 blocks.
A final piece of evidence involves two sites where I know that AMREs
have maintained populations for the past 20 or more years-Frozen Head
State Natural Area and western Putnam County. I've visited these sites
for about 20 years now, and each them has maintained a fairly large,
stable population of AMREs over the entire period. Is it likely that
these populations could have been present for 20 (or 20+) years but
that all the other nearby AMRE populations that I have mentioned
suddenly rose out of the primordial chaos quite recently? [The near or
total disappearance of AMREs from many low elevation sites in the Great
Smoky Mountains National Park since the time of Arthur Stupka
{mid-1900s} shows that this species is capable of changing its
distribution/abundance from time to time and from place to place; here
is another exception to test the rule I propose.]
Well, I doubt I will live long enough to see a project to survey all
4200 blocks in Tennessee, but it's nice to be involved in a smaller
survey effort like the forays that shows where we missed out because of
the way that the atlas project was conducted, and, again, I know there
was no other way to go with the atlas.
Steve Stedman
Cookeville, TN
You may see a map of AMRE distribution based on foray effort in the UCR
at this page of my website:
http://iweb.tntech.edu/sstedman/FORAY--ucr%20tn%20composite--AMRE%202007
-2010.jpg
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