A Great Northern Diver, also called the Common Loon as rears up for flight. Of particular note is the plump body that is held up by pointed but very short wings.

The Gaviiformes are referred to as loons in North America and as divers in UK and Ireland. Basically, the Gaviiformes are a family of aquatic birds that are mainly found in North America regions, northern Eurasia (Europe and Asia) and traceably in Africa. All the living Gaviiformes species have been classified to be members of a single genus, Gavia. They all belong to a single family, Gaviidae, and an order of their own, Gaviiformes. These species are phylogenetically arranged as:

• White-billed Diver (Yellow-billed Loon) - Gavia adamsii
• Red-throated Loon (Red-throated Diver) - Gavia stellata
• Black-throated Loon, (Black-throated Diver) and the Arctic Loon - Gavia arctica
• Great Northern Loon (Great Northern Diver) and the Common Loon - Gavia immer

Species Description

Gaviiformes grow to the relative size of a very large duck or a medium sized goose. They actually resemble each other in shape when the Gaviiformes are swimming. Loons have webbed toes to aid in swimming (gaining speed in water) or in floating. When Gaviiformes are flying, they resemble plump geese added seagull's wings. The wings are gigantic and quite in proportion to their bulky bodies. While swimming, the Gaviiformes hold their heads pointing slightly upwards as compared to the posture they assume in flight, with head drooped.

Both sexes of loons/divers are similar in plumage. On average male Gaviiformes are slightly larger than females. Their usual plumage in summer is a patterned black-and-white body, greys on the foreheads and white bellies. All diver species have distinct spear-shaped bills. In winter their plumage is dark gray in the body above, with light mottling on both wings, white chins and white undersides. It is easy to differentiate between the species from certain features like size, color of the necks, heads, back or bill etc.

Gaviiformes belong to a unique cult of birds whose young molt to a second set of down feathers immediately after shedding their first set instead of growing juvenile feathers. The trait is only shared with penguins (Sphenisciformes) and tubenoses (Procellariiformes), both close relatives of Gaviiformes.

Habitat

Gaviiformes are shaped and proportioned to aide excellent swimming and not walking. Their feet can propel them masterfully under and above water while the wings are fashioned to improve speed of a dive. The feet are thus placed far back on their bodies such that they are impaired to walk on land, something they avoid until when they have to nest.

Nevertheless, Gaviiformes are decent fliers as long as there is wind to aide their take off. They usually swim into a winds blow so as to pick up velocity adequate to propel their bodies into the air but once airborne they are very apt. this enables their long distance migration during winter. The Red-throated Diver is the only Gaviiformes that can take off initially from land.

Conclusion

Europeans refer to Gaviiformes as "divers", a name that probably derives from the bird’s feeding habits. Divers usually catch fish by swimming very calmly along the water surface until they mark a prey. Once the prey is marked, they abruptly plunge under the water and come out with a meal. For the North Americans the name "loon" originated most probably from an identical Scottish name for a Black-throated Diver. However, the term "loon" seems to refer to the bird's agile aquatic movements accompanied by its drawn-out calls.

Gaviiformes can live to be over 30 years old. This coupled by their ability to breed successfully yearly has helped the breed maintain a steady population over the years such that they are not considered an endangered species.