EagleCam Updates - 2014
April 1, 2014
With our first chick hatching on Friday, March 28th and the second egg hatching on Saturday, March 29th, there has been a lot of activity. From the photograph, it appears that they have also had a diverse diet. It seems that not only was fish brought in from the Potomac River, but even a squirrel appeared that may be saved as a snack for later. Although we have not been able to confirm if the third chick has hatched, with the help of our Momsters, we should hopefully be able to confirm this very soon.
Many people have been asking about the camera angle. Unfortunately, the National Conservation Training Center had to do some 'last minute' maintenance on the camera before the eagles nested. A critter (probably a squirrel) chewed the coax cable and we had no picture. During the work, the camera housing tilted a bit and it doesn't take much movement to change the view angle. With the eagles in nesting season, we can't disturb them to fix the camera angle. A truck and crane are required to reach the nest as the tree branches are not safe for climbing at 90 ft. So, we'll have to make the best of this until we can make a proper fix, after nesting season.
March 23-29, 2014
These eagles must start brooding their eggs as soon as they are laid, because in winter if they don’t those eggs will get cold enough to damage them. The result of this type of brooding process is asynchronous hatching with a brood consisting of young of various ages/sizes.
As the first egg was laid on President's Day - February 17 we should have expected the first hatching on Monday March 24 (after 35 days) and the second egg laid on February 20 should hatch Wednesday or Thursday, with the last egg hatching on Sunday. If any of the eggs got chilled during our challenging weather spell over the last month, they may not hatch. So keep your fingers crossed and think warm weather thoughts.
Because the weather is currently pretty cold, the young will have to hatch while being brooded; they cannot be exposed for more than a short time. If it doesn’t warm up soon it may be difficult for the parents to feed the hatchlings, if they have to be exposed for any length of time to do so.
With their long incubation times, one of the reasons the eagles do not typically nest in the later spring or summer is due to the high temperatures the young will be exposed to in the unshaded nest, with the danger of dehydration. It is a fact that the young in the nest will find it difficult to get water in any form except as moisture in the foods they eat, such as the flesh of fresh fish. The eagle parents don’t bring water in their gullets/mouths or absorbed on their belly feathers to allow the young to drink (as Old World sandgrouse do). Another important reason for early nesting is to the time hatching to correspond to the boom in prey populations - runs of suckers on the Potomac River and the hatching of goslings and other baby animals.
Almost all American birds with altricial young have little or no access to free water except from the moisture found in their food. Thus most Passerine (perching) birds don’t typically nest in the hottest months of the summer when even eating the moistest food items such as earthworms may not make up for the water lost in maintaining the hatchling's body temperature and water balance. Much like the eagles, Passerines nesting in spring time the hatch to correspond with the highest populations of caterpillars and other easy-to-eat invertebrates.
The current camera angle cannot be changed until the birds fledge in June. However as the young mature in the nest over the next 3 months it should be easier to observe them regardless of camera angle.
March 2-3, 2014
On March 2-3 the eagles endured an icy rain and snow storm (3-4 inches of snow accumulating), continuing to faithfully incubate their full clutch of 3 eggs. Nest views showed the female or male calmly sitting on the nest, completely surrounded by fresh snow in near zero temperatures. Only the largest raptors, including the great-horned owl and largest Antarctic penguins, such as the emperor penguin are massive enough to be able to incubate eggs in the mid-winter cold.
Both the female and male eagles have developed a brood patch, a spot bare of feathers on their stomach to be able to directly warm the eggs with their body heat, skin to eggs. The parents must turn the eggs regularly to ensure that all eggs in the clutch are incubated evenly and that all surfaces of each egg receive equal warmth. Regular turning moves an egg's contents by small increments, keeping membranes and the embryo from sticking to interior shell surfaces, which could cause embryo death. Hopefully none of the eggs have become chilled; if so they will not hatch. Only time will tell.
February 18, 2014
We have an egg! This year the eagles appeared to have delayed egg-laying at least 10-14 days during this stormy winter period, rather then risk losing their first clutch to snowfall as has happened a few times in the past.
The eagles, both female and male, begin to incubate the eggs as soon as they are laid. We can anticipate 1-3 eggs per clutch, laid one day apart. As this first egg was laid on President's Day - February 17 we should expect first hatching in about 35 days, on about March 24.
Any subsequent eggs will hatch a day or two later, resulting in young of different maturity levels in the nest.
Last year two young were successfully reared on a steady diet of freshly-caught Potomac River fish with an occasional turtle, waterfowl, snake, rabbit, groundhog and scavenged deer shank thrown in for variety.