image credit: Pixcontroller

HatchWatch Clock 2018

Egg 1 29 days (broken egg March 14)
The Hays HatchWatch Clock for egg 1 was started with a ‘guesstimated’ time of 11:59pm on February 12. (The camera stream was off between 2/12 at 6pm and 2/13 at 6am; egg rolling behavior was observed on 2/13 6:48am)
Hatchwatch: March 20 was the expected hatch date.
Lost egg: On 3/13 during the 4:29 egg roll, the egg began to present with an unusual appearance; this worsened through subsequent rolls and the egg eventually collapsed at 2:26am on 3/14. The male removed it from the nest cup at 10:03am and manipulated it with his beak; at 12:12 the female removed and consumed a clearly visualized embryo.
While there are no certain facts about what caused the egg to fail; the eagles did experience 3 consecutive nights of attempted intrusion on the nest by a raccoon during which time there was very vigorous and sustained commotion on the nest and this could have been a contributing factor. At day 29 of incubation the embryo in an eagle egg is approximately equivalent proportionally to the development of a chicken at day 17 of incubation. The embryo size appeared fairly consistent with growth that would have been expected around the same time frame.
H8 Age 263 days 22 hours 12 minutes 6 seconds
On February 15, 2018 the second egg was laid at 2:48pm and hatched on March 23 at 10:01pm after 36 days, 7 hours and 13 minutes.
Egg 3 39 days
On February 19, 2018 the third egg was laid at 5:56pm.
Hatchwatch: March 26 was the anticipated hatch date
Failed to hatch: When H8 hatched on 3/23, the discarded shell slipped over and capped the remaining egg on day 32 of incubation. “Egg capping” is very rare even in bird species that do not remove shells from the nest cup immediately. There is only a small amount of research on this and none of it is on eagles. The outcome of capped eggs is variable in these studies, but it does pose complications that may interfere with hatchability. First, “egg capping” can interfere with gas exchange through the shell that the embryo requires until it pips into the air cell. Second, chicks can only successfully hatch through the half of the shell that has the air cell (the blunt end). It was also unclear which end of the egg was ‘capped’ by the discarded shell. After 39 days the egg was declared no longer viable.

The Hatchwatch Clock counts up from the time the egg is laid.
Bald eagle eggs take 35 days to hatch on average.
First eggs may take longer as they are often not intensely incubated until the arrival of the second egg.