15 April 2021
Incubation began three and a half weeks ago at the Cathedral of Learning peregrine nest. During the day Morela and Ecco take turns every one to six hours.
Because peregrines delay incubation until the clutch is almost complete, nearly all the eggs will hatch on the same day. We humans predict Hatch Day will be between 20 to 26 April. My calculation is on the late end of that spectrum (here).
The peregrines know when Hatch Day is coming because they can hear the chicks inside the eggs. As hatching approaches, Ecco will spend less time on the eggs and Morela will take over.
Our first visual indication will be a pip, shown here in 2013. The chick will emerge in about 72 hours.
How can you tell if an egg has hatched while Morela is completely covering the eggs? Look for a discarded half eggshell away from the scrape, shown here in 2013.
Watch for Hatch Day late next week on the National Aviary falconcam at Univ of Pittsburgh.
(photos from the National Aviary falconcam at Univ of Pittsburgh)