EagleCam Updates - 2017
March 16, 2017
On Monday, March 13, the eagle pair experienced a significant snowstorm for the first time during this nesting season! The storm continued into the next morning completely immersing the female in snow. She incubated the eggs throughout the night until the male returned to begin incubating the eggs.
One might wonder how an eagle keeps itself and the eggs warm when heavy snow occurs. Bald eagles have unique body features and have also been shown to alter their behavior to modulate heat as temperatures decline (Stalmaster & Gessaman, 1984). Specifically, they retain body heat and minimize heat loss by a) sedentary behavior to slow metabolism, b) slowing blood flow away from the skin to the digestive system, and by having a body covered with over 7,000 feathers. To keep the eggs warm, the brood patch, a featherless area on the chest, is placed against the eggs to keep them at an optimal temperature (99oF), with occasional egg rolls to evenly distribute heat throughout the egg.
While most birds nest during the spring season, this time of the year is optimal for raptors in response to specific environmental cues such as photoperiods and food availability. Apex predators and their offspring need a significant amount of protein for energy and growth, which fish provides. So, egg incubation occurs midwinter, just before fish spawning cycles begin. Once air and water temperatures increase, fish move back to spawning grounds to lay eggs, and these areas are near the foraging regions of the nest.
If you follow the behavior of anglers, one of the first fish caught in the Potomac River each spring are carp. Interestingly, our survey of the 2016 nest revealed the eagle adults also sourced this fish mid to late March, and were immediately fed to the eaglets after hatching!
The success of the nesting pair seems possible despite the weather because this period aligns with the breeding patterns and distribution shifts of their preferred food source, and the animals possess a unique set of physiological characteristics. In essence, the breeding strategy is food related; that is as new food emerges within the habitat, the eagle adults are ensuring that an abundant food supply is available for the rapidly growing eaglets.
February 22, 2017
eggs have been laid! The first delivery occurred on February 17, 2017, and the
second was delivered early morning February 20, 2017. The male and female will
now share the task of incubating the eggs, trading between remaining in the
nest to protect and keep the eggs warm while the other hunts and forages. We
can expect up to three eggs, with the first hatch scheduled to occur on or
around March 24th. The second or third hatchings will occur in order of
delivery, resulting in a nest of eaglets at different maturity levels.
are known to drive avian reproduction such as hormonal triggers, temperature,
food availability, and most importantly, the photoperiod (changes in day
length). In 2016, the female laid its first egg on Feb. 9th when the daylight
hours were recorded at 10 hours and 30 minutes, according to the U.S. Naval
Observatory. The daylight hours for the February 17, 2017 delivery were almost
11 hours (10 hours and 58 minutes)! Interestingly, the eagle’s 2017
deliveries occurred 2-6 days and 6-8 days later than the 2015 and 2016
We will continue
to observe the adult pair working on the nest, exhibiting bonding behaviors,
and assuming the vital role of incubation for the next 35 -38 days.
February 8, 2017
In anticipation of a delivery, the bald eagle pair continues to bring sticks and grass to the nest shoring up the edges and rearranging the nest bowl center. Mating was observed several times in late November, and expectations are that the female will lay within the next week. Predicting the date of an egg delivery can be challenging, and certain factors play a role in shifting dates by one or two weeks.
American bald eagles breed during the winter or early spring when temperatures range from 25 to 45 oF (-4 to 6 oC).Temperature patterns have fluctuated in our region. In January 2017 alone, temperatures readings above 50 oF (10 oC) were recorded for 10 days. Yet bald eagle experts in Alaska believe that food availability and habitat quality drive breeding behavior (mating, nest building, etc.) more than temperature shifts (Hansen, 1987). However, extreme weather and temperatures (heavy snows or rains; below-average temperatures) can make food foraging challenging, leading bald eagles to advance or postpone egg-laying.
Fortunately, the eagles at NCTC harvest excellent food sources from the Potomac River, and this river has a man-made dam just over 1 mile from the nest site. Predicting the exact day of egg delivery may be challenging but the habitat factors within the region are supporting the annual nest success of this raptor pair and keeping those dates fairly consistent from year to year.
November 29, 2016
December is almost here in the Eastern Panhandle of West Virginia, and the pair of American bald eagles at the National Conservation Training Center in Shepherdstown, West Virginia, have been busy preparing their nest for another nesting season.
This is the 12th season that the nest has been active. The female first built the nest in 2006, and her current mate joined her in 2011. The birds are not banded with either metal or colored leg
bands, so identifying the birds is a matter of close observation.
Bald eagles reach sexual maturity, attaining a pure white head at the age of four to five years. During the last three years there was evidence of territorial competition as adult birds fought over
the nest site to determine who would claim the huge nest structure located at the top of a 100-foot-tall sycamore. Last year, single immature dark-headed birds, possibly born from the pair in years past, were seen in and around the nest, before the adult pair's nesting behavior went into full swing.
The bald eagle builds the largest nest of any North American bird and has the largest tree nests ever recorded for any animal, up to 13 feet deep, 8 feet wide, and weighing up to a metric ton. The
birds typically remain paired for as long as they live and will often
return to the same nests, with the birds living 25 years or more.
The larger female will lay 1-3 eggs and both birds will continually incubate them during the harshest winter and spring weather, in snow, rain and high wind. Bald eagles feed primarily on fish with
an occasional waterfowl, turtle, snake, groundhog, squirrel or rabbit taken as well. Roadkill deer and other animals are also consumed.
One to three young have been fledged most years at this location, with two young fledged in 2015, out of three young that hatched.
Bald eagles nesting in the region usually stay here their entire lives, as long as they have access to open water to feed on fish. The resident population appears to be growing and there is great
competition for nesting areas. The Chesapeake Region is also an important stop for bald eagles migrating from other parts of North America during spring and autumn.
Join us for this new nesting season. Please don't hesitate to ask us questions.
This project is a partnership between the US Fish and Wildlife Service, Outdoor Channel, and the Friends of the National Conservation Training Center. We also acknowledge the Town of Shepherdstown,
WV, the Hancock Wildlife Foundation for their support; and the many dedicated eagle fans from around the country, and the world, who have been with us from the beginning of this endeavor.