Birds
Picture

Hatching

Picture
Birds eggs are amniotic eggs. They are similar to the eggs of reptiles but theses have a hard outer shell. Most birds incubate their eggs until they hatch. When a chick is ready to hatch it uses a small tooth on it bill to make a hole in the shell. After much pushing, poking, and prodding by the chick the eggshell breaks open. Once the exhausted bird has hatched it collapses for a while allows it feathers to dry.  Both parents may be kept busy providing food for their hungry offspring.

Reproduction

Picture
In birds both male and female reproductive tracts open to the cloaca. The sex organs which are both internal often shrink in size when they arent being used. As birds repair to mate the ovaries and testes grow larger until they reach functioning size. Mating birds press their cloacas together to transfer sperm frm the male to the female. Some male birds have a penis that transfers sperm to the females cloaca.