Loons, also known as divers, are the size of a large duck. Their legs are located towards the back of their body, giving them optimum power when moving in the water but making them awkward when trying to move about on land. They have fully webbed feet and a streamlined profile. They have a long body that sits low in the water when they swim. Their bill is dagger-like making it a good tool for capturing their prey which includes primarily fish as well as mollusks, crustaceans and other aquatic invertebrates.
Loons have four basic calls. Their yodel call is one used to declare territory and only male loons use this call. Their wail call is reminiscent of a wolf cry and in it are hints of the phrase: where are you? Their tremelo call is used if loons are agitated in some way. Their hoot call is a soft greeting call murmured to their young, mates or other nearby loons.
Loons only venture onto land to nest. They build their nests close to the water's edge. Both parents care for their young, which leave the nest soon after hatching and ride on their parent's back for protection.
There are five living species of loons including the great northern loon, red-throated loon, white-billed loon, black-throated loon and Pacific diver.