The Black-necked Grebe is 28–34 centimetres (11–13 in) long. The adult is unmistakable in summer with a black head and neck and yellow ear tufts. In winter, this small grebe is white with a poorly defined black cap, which distinguishes it from the crisper-looking Slavonian Grebe (Horned Grebe in America).
In courtship the male gives a mellow poo-ee-chk call to the female.
This species breeds in vegetated areas of freshwater lakes across Europe, Asia, Africa, northern South America and the southwest and western United States. The North American subspecies, P. n. californicus is known as the Eared Grebe (or "eared diver"). These birds migrate in winter, mostly to the Pacific Coast where they range south to El Salvador on a regular basis; vagrants may occur as far as Costa Rica.
Black-necked Grebes of the nominate subspecies P. n. nigricollis in the cooler temperate regions of the Old World also winter further south, with many European birds moving to the Mediterranean area. The isolated southern African race, P. n. gurneyi is sedentary. It was named by South African ornithologist and author Austin Roberts in honour of the English bankers and amateur ornithologists John Henry Gurney and John Henry Gurney Jr..
Sadly the large breeding population in County Roscommon, Ireland discovered about 1915 fell victim to a drainage scheme in the late 1930s; at its peak there were an estimated 250 pairs.