[TN-Bird] Re: Shrikes and Quail - A War on Wildlife
- From: "Roger Applegate" <Roger.Applegate@xxxxxxxxxxx>
- To: <Dthomp2669@xxxxxxx>,<aves7000@xxxxxxxxxxxxx>, <TN-Bird@xxxxxxxxxxxxx>
- Date: Tue, 20 Jan 2009 17:10:44 -0600
All,
Few if any of you know me, but I am the TWRA Statewide Coordinator that deals
specifically with bobwhite and several other non-web-footed game birds. Some of
your emails were forwarded to me earlier today and I decided that I should
weigh in on this important issue. Alan Houston and Scott Somershoe have
already provided some key points relating to the history of land use that has
led up to our current situation.
Because we have large areas of the state that are either cotton/corn/soybean
agriculture, fescue pasture (overgrazed to boot), urban/suburban including
Walmart parking lots, and closed canopy forest, we have only small, often
postage stamp sized, habitats that are suitable for bobwhite. One covey of
bobwhite (average size 11) requires 40 acres of land that consists of patches
of low shrub, bare ground, and grasses and forbs (weeds to many people). This
is the stuff you get when farmland is taken out of cropping and allowed to
fallow and then succeed toward a developing forest. Ecologists call it
oldfield; I call it bobwhite habitat. It?s the same stuff bobwhites will be
found using in from southern New England to the western edge of Guatemala and
all points in between. The fine differences are in the specific plants that
make it up, and whether or not there are trees. Trees are irrelevant to
bobwhite unless they are too dense; the condition of a vast amount of our
forested land. They should not be closed-canopied and density should be less
than 60 ft2/acre of basal area. Basal area is the area taken up by a tree
trunk and if this figure for all trees growing on 1 acre adds up to more the 60
ft2 there is going to be a problem for bobwhite.
Back to the 40 acre point I made earlier, it REALLY takes more than just a plot
of 40 acres to truly make a bobwhite population that is able to sustain itself.
Each tract of 40 acres must be at least connected to another, and still
another, in chain fashion. This is because bobwhite coveys maintain themselves
on the landscape in groups of 10-11 which is the optimum size for survival. In
order to do this in the face of continual losses due to predators, disease,
toxins, etc., multiple coveys must be able to make contact so that small groups
may combine or excess members can join other undersize coveys. Without this
dynamic ability, the covey will eventually become extinct. So, our problem is
not just that we don?t have enough 40 acre plots of suitable habitat, but also
that they are not connected by very short (< 1 mile) corridors.
Another critical issue, and one that alarms me a great deal is the potential
for genetic contamination of bobwhite from release of domestic bobwhite.
Domestic bobwhite are any that can be raised successfully in captivity. They
are domestic because increasing studies are showing that they not only are
genetically distinct from wild birds, but extensive behavioral research has
shown that their development impedes their ability to survive under the range
of conditions found in the wild. With that said, we also know from a wide
range of evidence that some domestic birds released into the wild do manage to
survive IF WILD BIRDS ARE PRESENT. This works because, as mentioned earlier,
undersize coveys will take in new members to reach the optimum 10-11 number.
When this happens there is a risk that domestic genes will be incorporated into
the wild population and erode the genetic makeup that allows for the wild birds
adaptability.
While I have seen reference in one of the emails about TWRA somehow promoting
propagation and release of domestic bobwhite, I can assure you that we do not.
There are legitimate and useful functions for domestics in training dogs, field
trials, and for the commercial poultry market, but raising and releasing
domestics for replenishing or re-establishing bobwhite populations is a
dangerous waste. If used for training and field trials we recommend that they
be recovered using call boxes or shot rather than being allowed to remain in
the wild.
I have also noted mention of turkeys and the possibilities of turkeys eating
bobwhite chicks or eggs. I can assure you that in many years of study of wild
turkeys there have been not records of this happening. In the 1920?s or 30?s
there was an observation of a domestic turkey eating quail eggs in a farmyard.
The correlation between the increase in wild turkey and the decrease in
bobwhite is because of the land use changes as noted above. Since turkey
habitat is much more generalized, there is more of it than for bobwhite.
Therefore, there is the appearance that bobwhite are giving away to turkeys
when in fact it is habitat that is creating the change.
One final point I?d like to make relates to shrikes. First of all, shrikes can
make out fine in fescue pastures with barbwire fence around the margin and
clumps of multiflora rose scattered about, or locust, Osage orange or similar
thorny things. Bobwhites, while they can use some of the thorny stuff, do not
make out well in the fescue. In short, shrikes can actually live in places
that already probably don?t have bobwhite. So, if you see shrikes, you cannot
necessarily expect to see bobwhites although you could depending on the
composition of the habitat. Also, importantly, shrikes were impacted by
pesticides back in the pre-1970 period when organochlorines were causing egg
shell thinning in bald eagles and other raptors. Unfortunately, they have not
increased the way eagles and other raptors have; we can only speculate that it
is because something else changed. My guess, and it?s only a guess, is that it
has to do with grasshopper numbers. In the Flint Hills of eastern Kansas,
where there are far more grasshoppers than here, shrikes are everywhere.
I am going to quit this right now as it has already gotten longer than I
intended and many of you have probably already stopped reading and hit the
delete button anyway.
Roger D. Applegate
Small Game Coordinator
Tennessee Wildlife Resources Agency
Ellington Agricultural Center
PO Box 40747
Nashville, TN 37204
PH: 615/781-6616
FAX: 615/781-6654
Email: roger.applegate@xxxxxxxxxxx
UPS Address: 440 Hogan Road
Nashville, TN 37220
FedEx Address: 5107 Edmonson Pike
Nashville, TN 37211
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