Grebes are small to medium-large water birds with lobed, rather than webbed, toes.
The red-necked grebe has two subspecies, the nominate subspecies P. g. grisegena in Europe and western Asia, and P. g. holboelii (Holboell's grebe, named for Danish explorer of Greenlandic birds Carl Peter Holbøll) in North America and eastern Siberia.