{"id":20351,"date":"2022-09-07T15:20:50","date_gmt":"2022-09-07T13:20:50","guid":{"rendered":"https:\/\/www.discoverwildlife.com\/?p=1673"},"modified":"2022-09-15T15:51:30","modified_gmt":"2022-09-15T13:51:30","slug":"how-do-birds-eggs-form","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcwildlife\/rss_feed\/how-do-birds-eggs-form\/","title":{"rendered":"How do birds\u2019 eggs form?"},"content":{"rendered":"

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By Mike Toms\n \t\t<\/p>

Published: Wednesday, 07 September 2022 at 12:00 am<\/p>

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Here are the stages of egg formation, from a single cell to the finished egg<\/strong><\/p>\n

How birds\u2019 eggs form<\/h2>\n
An egg starts as a cell, and development is initiated by hormonal changes within the female\u2019s body.<\/p>\n
First the cell increases in size, then, over a period of a few days, a recognisable yolk is laid down.<\/p>\n
The growing egg passes down into the mouth of the oviduct (the tube leading from the ovary) where, assuming that viable sperm are present, it will be fertilised.<\/p>\n
The journey down the oviduct then continues irrespective of whether or not fertilisation has occurred (an unfertilised egg will still be laid, though obviously the embryo does not develop).<\/p>\n
At this stage, the egg membranes and albumen (egg-white proteins) are added, after which the mass is hydrated and plumped into the oval shape we all recognise.<\/p>\n
Next, the shell forms, from heavily calcified deposits on the outer membrane. The thickness of the shell varies between species, as does the colour and texture of its surface.<\/p>\n
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