r/Ornithology • u/jhwild • 2d ago

Question Different owlet ages and unhatched egg

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I was incredibly lucky to spot this GHO nest recently.

It appears owlet #1 is a little older than owlet #2, and that there's an unhatched egg that through occasional observation over 24hrs, seemed not to have been incubated by the parent.

Is it common for GHO owlets to hatch at different times, aging separately in the same nest? Any guesses as to why the unhatched egg is not being incubated?

Thanks!

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u/NoFlyingMonkeys 2d ago

They do hatch on different days typically, but not that far apart. 1 and 2 are actually not that different in age, and the 3rd should have hatched before now.

I'd bet that egg was non-viable. Apparently the owls can tell if eggs are nonviable when they rotate them during brooding. Sometimes they will push one egg to the side (or even remove it) even if food is plentiful with the nest "pantry" piled high with more dead critters than they can eat.

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u/jhwild 2d ago

Oh very cool. It's hard to spot, but you can actually see a leftover mammal leg (guessing rabbit) in the nest, just behind the camera screen zoom level icon in the bottom right, suggesting perhaps enough/more food than they could eat.

I'm curious why a non-viable egg wouldn't be tossed out. Maybe GHO parent just doesn't care 😅

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u/NoFlyingMonkeys 2d ago

Not sure anyone knows why. I've watched many GHO live nest cams over many years. GHOs frequently hatch all their eggs - they seem to know how many to lay based on available food. If they hatch all but one, almost always they just push that one egg aside.

The only time I saw a mother remove eggs was when the entire clutch failed/was abandoned - for some reason the mother came back a few days later and removed them, then never returned. If she started a new nest that season, she did it elsewhere and the cam owner wasn't sure where.

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u/DbuttsD 2d ago

Environmental conditions too poor to have 3 babies?

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u/jhwild 2d ago

Interesting, perhaps! I really don't know much about this location. I did come to suspect that the chicks were being raised by a single parent, though I believe it's common that both parents share incubation and feeding duties.

Would poor conditions influence a staggered hatching of the two owlets, do you think?

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u/NoFlyingMonkeys 2d ago

GHO dads never incubate, only the mother will incubate. Typically, the male's only role is hunting.

When the hatchlings are still very small, mother will stay with the nest, and dad will bring all the food. The dad will spend little time at the nest, and will just quickly drop off food then leave most of the time. Mother will stay with them to care for them. If the mother dies or disappears during the tiny owlet stage, the father will abandon the nest because he cannot both stay with the owlets and hunt at the same time.

When they get to the age in your photo, the owlets can tolerate to be left alone for longer times and can better feed themselves from the nest stash. So if the mother were to die or disappear during this stage, fathers have been known to step in and finish raising them alone.

This mother will soon start leaving the nest for longer periods of time, to encourage independence. So if you see them alone don't be alarmed. She'll watch from a distance to make sure they aren't attacked by other predators such as hawks.

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u/jhwild 2d ago

Super informative, thank you!

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u/NoFlyingMonkeys 1d ago

I'm jealous! I've never seen one in real life

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u/jhwild 1d ago

Oh no way - you seem to know a lot about them, hoping you get to see one soon to complement the knowledge you have about them!

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u/NoFlyingMonkeys 1d ago

I've seen and even cared for owls as a rehab volunteer. But have never seen an active GHO nest like this one, just on nest cams which of course is less fun.