[Bristol-Birds] Blue-winged drama at Hampton Creek Cove

From: "Wallace Coffey" <jwcoffey@xxxxxxxxxx>
To: "Bristol-birds" <bristol-birds@xxxxxxxxxxxxx>
Date: Tue, 10 May 2011 22:10:08 -0400
Biologists, researchers and serious amateur ornithologists
are beginning to get their science and minds around the puzzling
"Blue-winged Warbler" type bird that is nesting at Hampton Creek 
Cove State Natural Area near Roan Mountain in Carter Co.

It goes without saying that, at this hour, anyone's best guess is
a good one.  

It was discovered building a nest by Gary Cooper and Mike
Sanders of Bristol Virginia. 















                                                                               
photo by M Sanders

The drama is centered around the fact that this bird appears,
for all practical purposes, to be a male Blue-winged Warbler.
It carried nesting material and birders have seen that as well
as seen it build a nest.  Now it has five (5) eggs and it is
incubating.  It sings a male Blue-winged Warbler song.

The fascinating contradictions are that male Blue-winged
Warblers are not reported, in older literature, to build nests
or participate in nest building.  They also are not known to
incubate eggs.  The same is true of Golden-winged Warblers
where the males do not build nest or incubate.

A more complete search of recent literature has not been
undertaken.

But what would a strange-type hybrid do ?

These two species have a long and historic reputation for
frequently hybridizing where their breeding habitat overlaps.

The relatively short historical divergence of these species 
from a more common ancestor has created two birds with
very close-matching DNA and most capable of crossing.  

A study on Blue-winged and Golden-winged warblers 
represents a case of hybridization and the ecological aspects 
of speciation. The Blue-winged Warblers can live in a wider 
range of habitats and thus hybridizes with the Golden-winged 
warblers. Thus ecological aspects will eventually decide the 
fate for the Golden-winged warblers. 

This nest site is at higher elevations where the Blue-winged is
less likely to occupy breeding territories.  The Golden-winged
is in its element in the high elevation of Hampton Creek Cove.

For the most part, the Blue-winged is spreading more to the
east and invading the Golden-winged breeding areas where
it has the capability to genetically wipe out the later.

It is believed that Hampton Creek Cove has the largest known
population of Golden-winged Warblers nesting in Tennessee.

Researchers and managers believe the Carter County
population could become at risk.  It may already be
too late as the genetic makeup of all birds there may have
a significant genetic compromise.  The Brewster's Warbler
is a classic-known hybrid of the two species.  It is also known
from the area.  Some Blue-wing Warbler type birds have
been seen there during several recent years.

But, until Cooper and Sanders made their discovery,  there
had been no evidence that Blue-winged Warblers have 
nested at Hampton Creek Cover and surrounding areas.
But Brewster's Warblers have been showing up.

Also of significant suspicion is "where is and what is" the mate
in this strange nesting at Hampton Creek Cove ?

The best look was an apparent female-appearing Golden-winged
Warbler photographed as it was visiting the nest with the 
Blue-winged Warbler type bird that built it.  At first, based on
appearance alone, the Blue-winged was a field guide perfect
male and the Golden-winged was a color plate perfect female.
However, no Golden-winged type bird (male or female) has
been associated with the nest since that one observation.

No other Blue-winged warbler has been present other than
apparently the same bird which built the nest which apparently
is the same one incubating the eggs.




















                                                  photo by M Sanders

Sanders later got a photo of the nest when it had three eggs
but one seems suspiciously larger than the other two and a
little more heavily marked.  Today (10 May) there were five
eggs in the nest.  More photos were taken of the clutch today.

There is speculation that the male-looking Blue-winged Warbler
type building the nest and sitting on the eggs might actually be
reproductively a female.  But the outward expression of its genes 
gives it a male appearance and some behavior.  

For simplicity, we are calling the male looking bird a Blue-wing
Warbler for ease of communications.

Several biologists are trying to not only think thru the possibilities
but also what else to investigate and how to efficiently proceed.

Another has suggested that even if this is conveniently called
a hybrid Brewster's Warbler between a Blue-winged and Golden-winged,
it may still be a Brewster's that has, along its genetic path, seen
"back crosses" many times with one of the original Blue-wingeds
or Golden-wingeds or even other hybrids. We may never know without
good DNA material to study.

Nora Schubert has been conducting population censuses at the 
Hampton Creek Cove site.  She is continuing to be funded for
more such work this spring and already started in the field.

Nora is the modern-day face of the Golden-wing Warbler
studies at Hampton Creek Cove as has been Allan Trently
about 10 years ago and Melinda Wilson just a few years
before.  Melinda Welton has also made significant
contributions about 10 years ago.

Today, Nora began to identified and mobilize technicians
who will band warblers in the cove.   And, if color banding nestlings 
from this special nest is doable, then that too.  It could be 
helpful to get markers on the first offspring from a successful
Blue-winged type nesting -- whatever we have.

Let's go birding . . . .

Wallace Coffey
Bristol, TN
[Bristol-Birds] Blue-winged drama at Hampton Creek Cove

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