Loons, known as Divers in Europe, are group of aquatic birds found in many parts of North America and northern Europe. They are the size of a large duck or small goose, which they somewhat resembles in shape when swimming, but they completely unrelated to these waterfowl. There are 5 species worldwide and 5 species which occur in China.
The Phalacrocoracidae is a family of medium-to-large coastal, fish-eating sea-birds that includes cormorants and shags. Plumage colouration varies with the majority having mainly dark plumage, some species being black and white, and a few being colourful. There are 38 species worldwide and 5 species which occur in China.
Darters are frequently referred to as snake-birds because of their long thin neck, which gives a snake-like appearance when they swim with their bodies submerged. The males have black and dark brown plumage, an erectile crest on the nape and a larger bill than the female. The females have a much paler plumage especially on the neck and underparts. The darters have completely webbed feet, and their legs are short and set far back on the body. Their plumage is somewhat permeable, like that of cormorants, and they spread their wings to dry after diving. There are 4 species worldwide and 1 species which occurs in China.
Frigatebirds are large sea-birds usually found over tropical oceans. They are large, black and white or completely black, with long wings and deeply-forked tails. The males have inflatable coloured throat pouches. They do not swim or walk, and cannot take off from a flat surface. Having the largest wingspan to body weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week. There are 5 species worldwide and 3 species which occur in China.