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Osprey female in incubation mode, (Original Post) elleng Apr 2021 OP
Can't wait to see babies! SheltieLover Apr 2021 #1
DITTO, but have a couple of months to go! elleng Apr 2021 #2
WOW! That long? SheltieLover Apr 2021 #3
YES, but don't actually get 'shell' covering for a while, elleng Apr 2021 #4
So, they aren't in shells? SheltieLover Apr 2021 #5
MAYBE not yet; 'expecting.' Here's how it works, reposting: elleng Apr 2021 #6

elleng

(130,732 posts)
6. MAYBE not yet; 'expecting.' Here's how it works, reposting:
Thu Apr 15, 2021, 06:39 PM
Apr 2021

Put this together today, worth the time, for me at least:
Osprey Tales ← Osprey NestExtra! Extra! →

The Cloacal Kiss
Posted on April 7, 2014 by Harriett Raptor “To understand osprey reproduction, one must know a bit about osprey anatomy”, said Harriett. “The Doctor will explain”.
The cloaca
The cloaca is the posterior opening that serves as the only opening for the intestinal, reproductive, and urinary tracts of birds. The cloaca of males and females are the same. This confuses some humans. But, it’s not too hard to understand, if you take it step by step. . .
I do not think Harriett would mind showing us hers. Hang on a second. Let me ask.
OK, here it is: 🙂 (See pic)
Copulation
Copulation is the method in which a male bird fertilizes the ovum of a female bird.
The male and female press their cloaca’s together for a few moments to transfer sperm to the female. Each copulation last about 15 seconds; it is fast and furious. . .
Females in older pairs are fed more than females in younger pairs. It points to an inexperienced male.
Once they are settled at a site and start courtship feeding, mating can occur at almost any time.
An Osprey’s mating call consists of a brief “hew” and is repeated many times.
Most copulations take place at the nest because females spend most of their time there, but they can occur anywhere. No elaborate ritual or display precedes mating.
In general osprey copulations begin about 14 days before, and peak in the few days before the start of egg laying. They occur frequently, but only 39% of copulations result in cloacal kiss. It may take 160 copulation attempts to sucessfully fertilze a female to form a clutch of eggs.
Copulation occurs most often in the early morning. Female ospreys spent almost of their time (more than 95%) at the nest as they are fed there by the male. There is no association between courtship feeding and copulation, and hence no evidence that females trade copulations for food. Males maximized the time they spent at the nest with the female just prior to and during egg laying. . .
A male will land on a female’s back many times without this final contact being made. Studies have shown only 30-40% of attempts are successful. Early copulations stimulate the growth of eggs within the female’s ovary and strengthen the pair bond. The last 3 or 4 days before eggs are laid are the most critical for fertilization.
In a successful copulation the sperm travel to the female’s oviduct. This is where the various stages of egg development occur. First, the sperm fertilizes an egg which has been produced during ovulation and already has a yolk. Then the principal coating of albumin is applied before the outer and inner shell membranes are added. These stages take about 5 hours. Next the calcareous shell forms. The background pigments are laid down. The egg stays within the uterus for about 20 hours and tiny glands excrete the streaks and patterns that result in the darker markings on the shell. Finally the egg is laid. The eggs weigh between 60 and 80g and are about the size of duck eggs. The background color ranges from off white to pale brown, the mottling is red or dark brown. The first egg is usually the largest.' OK, we're all ready now, right?!
The Cloacal Kiss
OSPREYTALETELLER.COM

https://ospreytaleteller.com/2014/04/07/the-cloacal-kiss/?

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