The Red-throated Loon or Red-throated Diver (Gavia stellata) is a migratory aquatic bird found in the northern hemisphere. It breeds primarily in Arctic regions, and winters in northern coastal waters. It is the most widely distributed member of the loon or diver family. Ranging from 22–26 inches in length, the red-throated loon is the smallest and lightest of the world's loons. In winter, it is a nondescript bird, greyish above fading to white below. During the breeding season, it acquires the distinctive reddish throat patch which is the basis for its common name. Fish form the bulk of its diet, though amphibians, invertebrates and plant material are sometimes eaten as well. A monogamous species, the red-throated loon forms long-term pair bonds. Both members of the pair help to build the nest, incubate the eggs (generally two per clutch) and feed the hatched young.
First described by Danish naturalist Erik Pontoppidan in 1763, the red-throated loon is a monotypic species, with no distinctive subspecies despite its large Holarctic range. Pontoppidan initially placed the species in the now-defunct genus Colymbus, which contained grebes as well as loons. By 1788, however, German naturalist Johann Reinhold Forster realized that grebes and loons were different enough to warrant separate genera, and moved the red-throated loon (along with all other loon species) to its present genus. Its relationship to the four other loons is complex; although all belong to the same genus, it differs more than any of the others in terms of morphology, behavior, ecology and breeding biology, and may be the basal lineage of the genus.
The genus name Gavia comes from the Latin for "sea mew", as used by ancient Roman naturalist Pliny the Elder. The specific epithet stellata is Latin for "set with stars" or "starry",[6] and refers to the bird's speckled back in its non-breeding plumage. "Diver" refers to the family's underwater method of hunting for prey, while "red-throated" is a straightforward reference to the bird's most distinctive breeding plumage feature. The word "loon" is thought to have derived from the Swedish lom, the Old Norse or Icelandic lómr, or the Old Dutch loen, all of which mean "lame" or "clumsy", and is a probable reference to the difficulty that all loons have in moving about on land.
The species also has a short wailing call - aarOOao…aarOOao…, which descends slightly in pitch and lasts about a second; due to strong harmonics surrounding the primary pitch, this meowing call is more musical than its other calls. Another call — a harsh, pulsed cooing that rises and falls in pitch, and is typically repeated up to 10 times in a row—is used in territorial encounters and pair-bonding, and by parent birds encouraging their young to move on land between bodies of water. Known as the "long call", it is often given in duet, which is unusual among the loons; the female's contribution is longer and softer than her mate's.
The red-throated loon breeds primarily in coastal tundra, often on very small lakes. The red-throated loon breeds primarily in the Arctic regions of northern Eurasia and North America (generally north of 50°N latitude).
Adult loon in breeding plumage, reared up on the water with its wings spread. Among the loons, the red-throated loon is exceptional in its ability to take off from very small bodies of water.
Because its feet are located so far back on its body, the red-throated loon is quite clumsy walking on land; however, it can use its feet to shove itself forward on its breast.
As recently as the 1800s, the behavior of the red-throated loon was used to forecast the weather; according to the conventional wisdom of the time, birds flying inland or giving short cries predicted good weather, while those flying out to sea or giving long, wailing cries predicted rain. In the Orkney and Shetland islands of Scotland, the species is still known as the "rain goose" in deference to its supposed weather-predicting capabilities. The people of the Faroe Islands believed that if the red-throated loon miaowed like a cat, then rain was imminent, while a call of gaa-gaa-gaa or turkatrae-turkatrae predicted fine weather.