22 May 2020
Many who watch the Cathedral of Learning falconcam feel bad that Morela is incubating her eggs alone. Why isn’t one of her suitors, Terzo or Ecco, helping her incubate?
A clue comes from the answer to this question: What makes an an active raptor like a peregrine falcon want to stay immobile on eggs for more than a month?
Similar to us humans, the breeding season in birds is governed by hormones. Luteinizing hormones prompt testosterone production in males and progesterone (egg formation) in females. Then, as described in the Raptor Resource Project Blog …
Shortly before incubation, female birds (and male birds that share incubation duties) experience another big hormonal change. Prolactin, a hormone which promotes incubation in birds, rises sharply while other hormones decrease. Opioid peptides stimulate prolactin secretion, which may explain why even active birds become lethargic while incubating their eggs.— What Makes Birds Incubate, Raptor Resource Project Blog
Morela is an active peregrine but after she laid her second egg her incubation hormones kicked in and she slowed way down. In this Day in a Minute video from 18 May 2020 you see her lying flat and often asleep on the eggs. Ecco arrived at 6:38pm, photo below.
Ecco sometimes approaches the eggs as if he’ll incubate but mostly he’s in courtship mode (see this 13 minute video). On Tuesday morning before dawn (19 May 2020) he came to the nest and greeted Morela. When she left he approached the eggs, but didn’t incubate.
It appears that Ecco knows what to do but is unable to begin. I suspect his incubation hormones have not kicked in.
Morela will stop incubating when her prolactin shuts off. Meanwhile she’ll spend time away from the eggs on a daily basis, “stretching her legs.” Without steady incubation the eggs won’t survive.
(photos and videos from the National Aviary falconcam at Univ. of Pittsburgh)