08 December 2009

Eggs

All birds lay hard-shelled eggs--none give birth to live young because of weight problems. Try to find a diagram of the female reproductive system and what happens where and when (it takes 24-48 hr. = follicle to vagina):

Facts to note are that fertilization occurs in the ovary. When the follicle ruptures, the ovum starts down the oviduct and consists only of yolk and embreyo. Egg white is added in the oviduct. Albumen and the egg membrane are added in the isthmus. Finally in the uterus the egg shell and pigment are added.
All this takes a tremendous amount of energy (?) (classically assumed, anyway: time of molt may actually be much more critical). (Never hassle molting chickens--they are liable to go into shock).


If young Blue-footed Boobies leave the guano circle around the "nest," the young are ignored by the parent and the young starve.

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