I know there are a lot of knowledgeable people that read these emails.
The question is: From the time of fertilisation how may days is it till the egg is laid? If another egg is laid a few days later is it fertilised on another occasion?
The question is about the White-bellied Sea-Eagle but I am sure there is no specific info on them but any info on birds of the same size would be of interest.
Thanks Geoff Hutchinson ===============================
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Hi Geoff,
I think in most bird species it takes about 2 days. Once the egg has been fertilised, the ovum is enveloped by the infundibulum (the site of fertilisation). Then the outer layers of the egg (cuticle, crystallisation layers and the eggshell membranes) begin to form. While all this happens, the egg descends down the oviduct.
Stephen Ambrose Ryde NSW
Hi Geoff,
Re Q1. That is hard to know without doing experiments on captive birds, where you could control these things. I wonder though if it has been done and why someone would bother. There is another component to the question and that is what is the time delay from copulation to fertilisation? My guess is that in birds it is short. But not in all animals. In many insects this may be months or maybe years, where the female mates only once and then goes on breeding for the rest of her life. In some bats I believe it is months, when the mating occurs months before the ovulation and the sperm is stored waiting for the ovulation. But I am not aware of any birds doing that.
In birds it may well vary between species but my guess is 2 or 3 days. I’m sure there would be books with info about this but I don’t have time right now. Info may be most likely available for chickens and a few other domestic species.
Re Q2. Again hard to know but most likely in practice yes. During the time when the eggs are being formed most birds copulate frequently. So unless you have found a non randy bird, there is likely to be several copulations during the period of possible fertilisation and egg laying. So I strongly suspect it is more likely than not that the copulations leading to the fertilisations leading to the egg laying on different days were different copulations.
This is not a comment on White-bellied Sea-Eagle as distinct from any other bird.
Philip
Geoff,
I can’t help you with WBSE, but in chickens, it is around 23-24 hours and in Cockatiels 2-3 days. Diet of the female can cause the actual period to vary a bit.
Cheers,
Carl Clifford
I know there are a lot of knowledgeable people that read these emails.
The question is: From the time of fertilisation how may days is it till the egg is laid? If another egg is laid a few days later is it fertilised on another occasion?
The question is about the White-bellied Sea-Eagle but I am sure there is no specific info on them but any info on birds of the same size would be of interest.
Thanks Geoff Hutchinson ===============================
To unsubscribe from this mailing list, send the message: unsubscribe (in the body of the message, with no Subject line)
http://birding-aus.org ===============================
===============================
To unsubscribe from this mailing list, send the message: unsubscribe (in the body of the message, with no Subject line)
http://birding-aus.org ===============================