[Bristol-Birds] Bald Eagle egg laying may be a Valentine gift !

From: "Wallace Coffey" <jwcoffey@xxxxxxxxxx>
To: "Bristol-birds" <bristol-birds@xxxxxxxxxxxxx>
Date: Tue, 30 Mar 2010 22:43:59 -0400
The young Bald Eagles seen in the Avens Bridge nest
location appear to be about 10 days of age -- give or
take a couple of days.  This is not absolute but as
close as we can project it at this time.

Given the 35-day incubation period, we can count the
egg laying back to the middle of February.

Now we can set our memory reminders to expect egg
laying by the Bald Eagle at our latitude and elevation
(2,100 feet) in this case as beginning each year near
Valentines Day !  This is a useful reminder because
we have a memory benchmark for a full clutch of 
Common Raven's eggs in the nest on St. Patrick's Day
-- March 17.

So now we can begin to expect the Bald Eagle to have
eggs here about a month before the Common Raven.

On 27 March 2009, the Russell County Bird Club had
a field trip to see the Avens Bridge eagle pair nest  
and were able to tell that there were small eaglets in
the nest.  This suggest that this pair's biological breeding
clock is on the same time this year as compared to last
despite the continuous snows and record cold spell
during January and February.

On 20 February 2010,  Dave Worley, Tom Hunter and
some of the participants of the Bristol Bird Club 20th
Annual Golden Eagle Winter Field Trip to Burkes
Garden in Tazewell Co., VA, saw an adult Bald Eagle
at the nest across from the Burkes Garden General
Store.  Two weeks later on 7 March 2010, Stan Bentley
and his wife, Mary Ann, from Pulaski, VA, saw the 
Bald Eagles at the Burkes Garden nest and one bird
was incubating and appeared to be turning eggs.

The elevation of that nest is 1,000 feet higher than the
Avens Bridge nest and at 3,100 feet.  It is at a more
northern latitude (Avens Bridge = 36.6222, Burkes
Garden 37.0981 degrees) and about 50 miles 
northeast of Avens Bridge.

Given these dates, it might be safe to suggest that
the Burkes Garden pair is operating on approximately
the same biological clock as the Avens Bridge pair
with maybe a lag of a week or so for the
Burkes Garden pair.  If they nest there again next
year, we'll more closely tune this assumption.

This data and projections give us clues to when we
can expect eagle nest activity with eggs and young.
Now that eagles have young, birds seen carrying
prey should be tracked as closely as possible in
order to locate as many nest sites and further
document the expansion of Bald Eagle throughout
our region. But eagles will continue to migrate 
thru this area for awhile.  Records show that we
have had Bald Eagles at South Holston Lake in
every month of the year for almost a decade.
That is the accumulated records.  It does not 
mean we have birds every month of every year
but they are possible any month of any year.

Let's go birding . . .

Wallace Coffey
Bristol, TN
[Bristol-Birds] Bald Eagle egg laying may be a Valentine gift !

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