Horned grebe

The horned grebe, also known as the Slavonian grebe (Podiceps auritus), is a small, vulnerable waterbird. It has two subspecies: one that breeds across Eurasia (P. a. auritus) and another that breeds in North America (P. a. cornutus). The Eurasian form ranges from Iceland to the Russian Far East, while the North American one spans most of Canada and parts of the United States. Breeding has been noted sporadically in Greenland, though it is not a regular or well-documented occurrence. The American name "horned" comes from the orange-yellow crest feathers above and behind the eyes. The English name "Sclavonian" first appeared in George Montagu's 1802 Ornithological Dictionary, derived from Scalovia, an old name for northern Prussia, referencing the species' main European breeding area. The spelling was changed to "Slavonian" by Hartert in 1912 without explanation.

Carl Linnaeus formally described the horned grebe in 1758 in his Systema Naturae, calling it Colymbus auritus. He gave the type locality as Europe and America, later restricted to Vaasa, Finland. It now belongs to the genus Podiceps, introduced by John Latham in 1787. The genus name combines Latin podex ("vent") and pes ("foot"); the specific epithet auritus means "eared" or "long-eared," and the subspecific name cornutus means "horned."

The bird is 31–38 cm long, with a wingspan of 55–74 cm and a weight of 300–570 g. It has a moderately long neck, a flat forehead, and a black-feathered rear crown. Its beak is straight, pointed, and tipped with white. In breeding plumage, it sports bright, erectable "horns," black fan-shaped cheek feathers, and a red-and-black body. The neck, flanks, lores, and upper chest are chestnut brown; the crown and back are black; the belly is dull white. Males are slightly larger and brighter than females but otherwise similar. Non-breeding plumage is black and white: the neck, chest, and cheeks are white, while the back and crown are dull black-grey. A straight line separates the crown from the cheeks behind the eyes, and the "horns" are absent. Juveniles resemble non-breeding adults but are duller white, with a brown-tinged back, a less distinct cheek-crown line, and a paler beak. Chicks are fluffy, with a dull grey back, white belly, and distinct black-and-white striping on the face and neck.

The two subspecies are similar in size but differ subtly in plumage. P. a.