[Bristol-Birds] Biologist says army ammunition plant eagles always build on heron's nest.

  • From: "Wallace Coffey" <jwcoffey@xxxxxxxxxx>
  • To: "Bristol-birds" <bristol-birds@xxxxxxxxxxxxx>
  • Date: Tue, 21 Feb 2012 14:20:54 -0500

Bruce Cole, a natural resources biologist with the sprawling Holston Army
Ammunition Plant located at the edge of Kingsport in Hawkins County, TN,
called this morning to share his thoughts and experiences with Bald Eagles
at the nests of Great Blue Herons.  He has been reading Bristol-Birds reports
about the Boone Lake pair.

The ammunition plant was constructed 1942-1944 for use by the government 
contractor and its two sites, connected by a railroad track, total 6,000 acres.

Bruce had been intending to catch up with me since reading that the Bald Eagles
at Boone Lake were frequenting the Great Blue Heron nest and then the eagles
moved on.

He was not surprised that the herons had arrived and were back at the nest.

Déjà vu, over and over and over again !

"That's what eagles and heron do here at our area," he told me.  "I've 
that many times."  He believes the Boone Lake eagles are still nearby and may
not nest this year.

Cole has a Bald Eagle nest which is located on the plant's property and was
the first ever known in the upper Holston River area.  Bald Eagles have nested
there almost yearly since the first in 2005 -- eight years !!  They have fledged
9 young and are believed to be the mother of all pool sources for birds building
nest throughout the region.

Cole said that Greg Lee worked his position at the plant before Cole came in

Lee arrived at the Hawkins County plant site in 1996 and a pair of eagles came.
They added nest material to a Great Blue Heron nest but never nested.

Ever since then, the eagles have been present at the Clay Island rookery site
on the river in the plant and, each year, the Bald Eagles have established
presence on a Great Blue Heron nest, usually adding nesting material.

Eagles have nested at the plant since 2005 and are now in their eighth breeding 
season and nesting regularly. One year the nest failed when a major windstorm 
the upper branches of the nest tree and the nest fell.  They built back and have
continued yearly.

The nest is located on Clay Island in the Holston River between river Mile 
Point 138-139  (36.5254°N, 82.6527°W),  fully within the security area of the 
fenced plant property.  Cole said the nest was built in the tallest tree 
around.  It easily towers 20-30 feet above any other.  He estimates the nest 
to be about five feet in diameter and maybe four feet deep.

Cole said the eagles had expanded the nest by about double its 2005 size.  It 
is much deeper and his usual hillside viewing spot no longer allows him to 
observe as much about the contents as he did earlier.  

He says that every nesting effort at the plant, including the nest that is there
now, has been built on that of a Great Blue Heron's and sticks and materials
taken from other Great Blue nests were used to build the present nest and the
one blown out in the storm.

Of note is that various pairs of Bald Eagles, some with different age and sex
and plumages by age, have been present at the nest site throughout the
breeding season since Lee saw the first in 1996 but that went on for eleven
years before eagles actually were successful building a nest.

He said the eagles would roost in the large Great Blue Heron rookery on the
island but herons abandoned and moved up in a nearby creek area of the plant 
once the eagles actually built a nest and began this eight year run.

He believes eggs were laid 8 Feb 2012 and the birds usually incubate there
for about 35 days.  He expects young to hatch about 13-14 March.

In 2009, there were 121 Great Blue Herons nesting in the plant rookeries and
about 89 Double-crested Cormorants.  In the nesting season of last year, the
cormorants had increased until, for the first year, they out numbered the
Great Blue Herons.  Last year there were 88 herons and 101 cormorants.

The Bristol Bird Club held a field trip into the ammunition plant 8 April 1995. 
That was the only time birders have been allowed into the plant.  The area 
contained an estimated 57 Great Blue Heron nests and we found five 
Double-crested Cormorants sitting on nests.  We had about 20 birders take 

Only four Tennessee counties had historical breeding cormorants and the 
rookery, at that site in 1992, represented the first documented observation 
of nesting Double-crested Cormorants in Tennessee since 1955. 

The Double-crested Cormorant was found there by Caldwell and Copeland, 
17 April 1992, when five individuals were on the river during breeding season. 

On 14 May 1992,  the biologists observed a cormorant carrying nest material 
in its beak. Two cormorant nests, each with two nestlings, were observed 
22 June 1992 on Clay Islands. These nests were found within a nesting 
colony of Great Blue Herons.

A nesting record for the cormorant in Sullivan County on the South Fork Holston 
River was about 6 miles upstream of the ammunition plant.  Rick Knight found 
a bird on a nest 30 March to 30 May 2006 just downstream from Netherland Inn. 
The nesting attempt failed.

Downstream at Bird Island on Cherokee Lake in Hamblen Co., Michael Sledjeski 
and Leslie Gibbens did a survey of the wading birds found nesting there on 
2 June 2008 and they determined 142 Double-crested Cormorant nests and 
450+ birds; 78 Great Blue Heron nests and 250+ birds; 3 Great Egret nests with 
14 birds, 33 Black-crowned Night-Heron nests and an estimated 125 birds.  

Nationally, cormorants showed a 30-year colonization period (1920s-1950s), 
followed by a 20-year decline (1950s-1970s) and, most recently, a 30-year 
resurgence (1970s-2000s). This resurgence is believed by some wildlife 
to be a result of legislation protecting cormorants, a decrease in commercial 
a decrease in human persecution, and a lower level of toxic chemicals, such as 
PCB and DDT.

Let's go birding . . . .

Wallace Coffey
Bristol, TN 

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