The enzymes that act inside the small intestine are amylase, protease, and lipase. Amylase acts on starch and breaks it down into small carbohydrate molecules. Protease acts on proteins and breaks them down into amino acids. Lipase breaks down dietary fats into smaller molecules called fatty acids and glycerol.
Sandhill Cranes mate for life, choosing their partners based on dancing displays. Displaying birds stretch their wings, pump their heads, bow, and leap into the air. Although each female usually lays two eggs, only one nestling typically survives to fledge.
Mate for Life. In nature, some birds are known to mate for life, while others choose a new mate every breeding season. Cockatiels are one of the birds who have been observed to mate for life. In the wild, they choose their own mates and stay together. Cockatiels in captivity may choose a mate if they're in the same aviary or store, or they may be given a mate by their owner.