Duck egg

Compared to chicken eggs, these are larger, higher in fat, more colorful, and more flavorful. They're sometimes contaminated with bacteria, so make sure you cook them thoroughly. 

Egg = chicken egg

One egg contains about one tablespoon of egg yolk and two tablespoons of egg white and weighs about two ounces without the shell. Eggs come in different sizes. Most recipes assume that you're using large eggs.

Quail egg 

Capelin roe = masago

Japanese cooks use these tiny, fluorescent eggs as a topping for sushi.

Preserved Eggs = salted duck eggs = yandan; pidan (Mandarin) = haham don; pei don (Cantonese)

In China, and among the Chinese communities throughout South-east Asia, preserved eggs are a very popular delicacy. There are two main types, and both use duck eggs. This is partly because duck eggs are bigger and have a stronger flavor than hen's eggs, but also because the yolk of a duck egg contains more fat than a hen's egg. The more common type, much flavored in southern China, is the salted duck egg. The other, which has more universal appeal, is the famous thousand-year-old egg.

Both types of preserved egg are made by a similar method; it is the material used in the process that are different. Basically, salted eggs are made by coating raw duck eggs in a salt and mud paste, then rolling them in rice husks until they are completely covered. At this stage the eggs are packed into an earthenware urn, which is tightly sealed and stored in a cool, dark place for 30 - 40 days. Thousand-year-old eggs are nothing like as old as their name suggests. They are raw duck eggs that have been covered with a mixture of wood ash and slaked lime and left for up to a hundred days. By the time they are turned to pale brown jelly and the yolks will be creamy and tinged green.

The two types of preserved egg smell and taste quite different. As might be expected, the former are quite salty. Thousand-year-old eggs taste milder, but still have a definite aroma and flavor.

Salted eggs must be cooked. They are often eaten on their own, or used as part of the filling in cakes for festivals. Thousand-year-old eggs need no cooking. Sliced and seasoned with soy sauce and sesame oil, they are often served as a starter, or chopped and added to congee and eaten at breakfast time. They can also be used in a delicious omelette, with pork and fresh hen's eggs.