The Yellow-billed Loon (Gavia adamsii) is the world's largest loon and one of the most sought-after winter visitors for Swedish birdwatchers, a massive Arctic diver that reaches Swedish waters in small numbers each winter. It measures 76-91 cm with a wingspan of 135-160 cm, distinctly larger and heavier than its black-billed relative and closer in size to a Greylag Goose. The single most important field mark is its powerful, slightly upturned bill, a striking yellow-ivory that can be picked out at long range. In the winter plumage typically seen in Sweden, the upperparts are greyish-brown with diffuse markings and the underside white, with a faint dark neck stripe and a paler ring around the eye giving a characteristic "headband" look. The rarely seen summer plumage shows a velvet-black head and neck with a subtle greenish sheen and a back speckled black and white.
In Sweden the species is almost always silent; on its Arctic breeding grounds it gives a deep, mournful, oboe-like "ua-uoo" call that carries far over the water, though this is rarely heard so far south. It breeds at coastal lakes and river deltas across Arctic Siberia and Alaska, with part of the population in northwestern Canada, and winters at sea along the North Atlantic and North Pacific coasts. In Sweden it is a regular but scarce winter visitor, with 10-30 records annually; the best sites are the Gulf of Bothnia during cold winters with ice, particularly the Haparanda archipelago, Piteå and Luleå, with occasional birds also along the Bohuslän coast and in the Öresund. It is an outstanding diver, able to reach depths of over 50 metres hunting fish, swims low in the water, and needs a long run to take off; on land it is nearly helpless and rarely comes ashore voluntarily. Sightings in Sweden are almost always of single birds, sometimes with its black-billed relative. Globally the species is assessed as Near Threatened.
Read about this species in Swedish →