Likely To Hatch?

17 May 2020

Everyone was surprised when Morela laid a second egg yesterday at the Cathedral of Learning peregrine nest and appeared to start incubation. It was a week since she laid her first egg and it’s unclear if either male, Terzo or Ecco, will assist in incubation. Are the eggs likely to hatch?

Fertile eggs will hatch if they are kept at the right temperature — constantly — for the right amount of time. Once the eggs’ temperature is raised by the skin (brood patch) of the parents laid against the shell, the embryo starts to develop into a chick. If the temperature is not constant or it does not last for the right number of days the developing embryo dies.

Delaying the start of incubation is a normal strategy for many species. Ducks, shorebirds and peregrine falcons wait to start incubation until the clutch is (nearly) complete. This is not harmful to the early eggs as long as they are kept from freezing and moisture.

However, once incubation starts it must not stop until the job is done. Uncovering the eggs for more than a few minutes, depending on outside temperature, is fatal because the developing embryo is too far along.

So when Morela appeared to incubate for several hours yesterday (see video) and then stopped overnight, the chances for her eggs dimmed.

The real test will be whether her incubation efforts are constant and whether Terzo or Ecco help her. It takes a pair of peregrines to raise a family. If no male helps incubate, the eggs won’t make it.

Read more about how eggs develop in this vintage article: Incubation Chamber.

(photos and videos from the National Aviary falconcam at Univ. of Pittsburgh)

8 thoughts on “Likely To Hatch?

  1. This is so interesting.
    Do you by chance know anything or have hear about the peregrines on the Rachel Carson building in Harrisburg. I like to tune in once in awhile and there is nothing on any of the cameras. Last date I saw them was May 11 and they were still big fuzzy balls.

  2. Thank you so much for you dedication in posting the updates. I cringe when I see Morela off of her eggs, and you always answer the questions I have regarding things like that. Many thanks!

  3. It appears that Morela is trying to do it all by herself. Although not able to watch that often, I don’t recall seeing either male. Has Ecco or Terzo been seen bringing food to Morela? If she has to hunt for herself and kept challengers/predators away, the future of her eggs is not looking good, but I will try to stay positive.

  4. It is 6:20PM . Morela is standing over the eggs and calling for someone to come help out. nobody is coming.

  5. Poor Morela, it seems like she’s trying to incubate the eggs but no one is helping her. I’ve seen her get off the eggs and stand there calling, or sometimes she is sitting on the eggs and calling, but I haven’t seen either of the males come to help her. It would be a shame if it turned out that Ecco is actually Dori’s mate and just wanted to drive off Terzo because he considered the Oakland nest too close, and left Morela with no mate.

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