CCB Eagle Nest Blog

On Friday Jan 20 at 2:50pm a 2nd year juvenile (male I think) paid a visit to the bald eagle nest at Norfolk Botanical Garden (Photo 1). It did not go unnoticed by the two adults who chased it off almost immediately. The juvenile is not banded so could not be a NBG eagle. Later about 4:35 while the male with his new dark tailed female were in the nest, the juvenile returned to sit on an outer branch of the nest tree (Photo 2). That set both adults to screaming (Photo 3). And once again the juvenile was chased off (Photos 4 & 5).

Update – A viewer has correctly pointed out that these are two different juveniles. Today there were two juveniles seen flying together at NBG.

We do not yet have all our questions answered about the death of the adult female bald eagle at Norfolk Botanical Garden on Jan 6, 2012. However, as of yesterday Jan 20, 2012, we do have the answer to one question. Is the current female that the male is with the same female that he had been with since Sept 2011? The answer – NO! The current female is yet another fifth year bald eagle in her first breeding season. Look at her tail feathers that have brown/black in them unlike the prior female. She is also molting head feathers with a distinct bare spot in the top of her head, and her bill is still turning yellow with grey. She also has many more older, more worn, lighter brown body contour feathers. Eagle cam photos Jan 21, 2012.

Statement prepared by Dr Bryan Watts, Director of The Center for Conservation Biology, with respect to the death of an adult and a juvenile bald eagle at Norfolk Botanical Garden.

Eagle Mortality Norfolk
Botanical Garden

On a global scale, our electrical infrastructure kills millions of
birds annually.  There are three common
ways that birds are killed when interacting with transmission or distribution
lines.  The most common of these is
referred to as pole electrocution.  Birds
perching on power poles are electrocuted when they come in contact with two
conductors and complete a circuit.  To
overcome this problem, power companies have retrofitted power poles in areas
known to have problems to prevent birds from making these contacts.  The second most common cause is referred to
as a mid-line electrocution which occurs when a large bird flies through the
lines and is able to complete a circuit by touching two wires with its
wingtips.  The third form of mortality is
when a bird flies into lines does not complete a circuit but is killed by the
trauma.  Bald eagles are particularly
vulnerable to mortalities related to the electrical infrastructure because they
are large enough to bridge the gap between conductors.

In a recent investigation of 62 eagle mortalities caused by power lines
within the upper Chesapeake Bay, Bryan Watts and Libby Mojica from The Center
for Conservation Biology determined that both line location and context had a
significant influence on the likelihood that they would kill eagles.  Lines that are near water or foraging areas
are crossed regularly and have a greater likelihood of being problem lines.  Lines that are exposed in open areas are much
more likely to kill eagles compared to those that are associated with screening
vegetation.  This is because tall trees
planted near electrical lines serve to shift the flight line of eagles above
the power lines.

In just the past 2 weeks, two eagles have been found dead within the
grounds of Norfolk Botanical Garden that were associated with power lines.  The first was an adult-plumaged female and the
second was a juvenile-plumaged bird.  The
juvenile clearly died by trauma-related mid-line strike, and the adult is suspected
as having also died by trauma-related mid-line strike.  The extent to which these mortalities were
facilitated by interactions with other eagles is not clear.  We have very little information on causes and
rates of eagle mortality but such events are likely much more common than we
currently know.

The eastern gray squirrel is a very common small mammal (rodent) in the mid-Atlantc region. They are tree squirrels (rather than ground squirrels). They usually make their nests in holes in trees or leaf nest at least 25 feet above the ground. They can have 2 litters of 3 to 5 that are born blind after a 44 day gestation period and take 2 months to wean. Occasionally they will take advantage of other places to build their nests. One pair has done that at Norfolk Botanical Garden. They have built their nest in the underside of the current bald eagle nest. Their nest has two entrances – lower left and lower right. Eastern gray squirrels mate in this region in Jan-Feb and June-July. From The Encyclopedia of Mammals by David MacDonald – In tree squirrels and chipmunks, receptive females attract males using chemical signals and vocalizations, then lead the males on long, spectacular mating chases that may last from 4 to 10 hours. I have been seeing that activity in my yard for the past couple weeks.

Today about 4pm I watched as a squirrel emerged from the left underside of the current NBG bald eagle nest several times, and climbed into the nest pocket above. Why? What was it doing? It was stealing pine straw from the bald eagle nest and taking it into its nest in the underside of THEIR – the eagles and squirrels – nest in preparation for breeding season. It is a whole lot closer that going all the way to the ground and back up the tree. Smart squirrel!! Cooperative nesting.

1 – Emerging from its left nest entrance 2 – Picking up pine straw 3 – Holding in its mouth 4 – Scampering back to its nest

Overnight Jan 8/9 both the adult bald eagles stayed in the nest tree, with the male in the nest and the female on the back branch. Just before 7:00am the male moved to the back branch next to the female and at 7:02 the pair mated for the first time this breeding season.

Both adults came to the nest about 4:45 today. The male stayed until 5:05. The female then layed in the nest squirmimg around in the grass and straw they brought a couple days ago forming a pocket in the nest. The female left about 6:00pm.

Do you wonder what all the raucus noise is about and why there are swarms of birds chasing a raptor? That action is called mobbing. It is often the best way a birder can locate a raptor. Mobbing is sometimes triggered by no more than the shape of a raptor rather than any immediate threat. A raptor may be set upon by a single bird or by a large mob. For example, in 2006 when the first eaglet fledged from its nest at Norfolk Botanical Garden several of us were there. What started as one crow chasing this fledgling on its first flight was soon nearly 100 crows that came from every direction. For that eagle, harassment by crows and other birds was now to be the way of life. They will sometimes sit and tolerate the frenzied attack for a time, but will soon fly away to escape the attack usually without any retalitation. Mobbing is not completely understood but the attacks and vigorous vocalization is believed to encourage the “enemy” to move on, and occurs most often during breeding season. Sometimes several species will combine their efforts to drive off an intruder into their territory. Mobbing occurs among many species of birds, not just raptors.

These photos were taken on the North Landing River near Honey Bee Golf Course in Virginia Beach over the past few weeks showing juvenile eagles being harassed by crows. The red-tailed hawk was being dive-bombed by a crow that was nearly the same size, and responded by screaming but also flew off to get away from the scolding crow. (Photos copyright by Reese F Lukei Jr)

This morning January 1, 2012, both adults arrived at the nest together at 6:45. The female stayed only about 6 minutes and then flew off. The male left and returned with his talons full of grass and straw. He left again and did the same thing returning with more grass, this time calling for his mate who did not respond. He then left at 7:56 and has not returned. The female arrived about 8:30 with grass in her talons, stayed a few minutes and left. Now the nest has a pile of grass and straw. The new year has begun.

December has been one fantastic month for photographing and identifying Norfolk Botanical Garden juvenile bald eagles that are wearing purple identification bands. Today was another of those days. This morning Duane Noblick captured images of 2009 NBG eagle banded HK, the younger brother of Azalea who is banded HH and wearing a satellite transmitter – http://eagletrak.blogs.wm.edu. Duane’s photos enable us to positively identify HK by its distinctive plummage, especially tail pattern, back and wing pattern. His photo’s are in Photographers Nest at www.norfolkeagles.com. This afternoon I was fortunate to be off Ware Neck Rd in Virginia Beach on the North Landing River that runs through the Honey Bee Golf Course when HK came fishing. He made one pass hitting a fish, a shad I believe, and knocking it about 3 feet into the air but not grabbing it. Note the double-crested cormorants and great blue herons watching the action. HK made a circle around and came in again and this time he was successful. Click photos to enlarge. (Photos copyright Reese F Lukei Jr)

Today for the first time this season the two NBG adults came to the nest in the middle of the day. Here are some of the images they left for all of us.

Both:

Male:

Female: