Horned grebes have relatively straight, short, fairly thin bills. If you are close enough to see the yellow tip, then you are looking at a horned grebe, because the bill is entirely dark on eared grebes.
The blackish crown on horned grebes ends at the eye and contrasts sharply with the white of the lower face. Another character is the white spot between the eye and the base of the bill on winter-plumaged horned grebes. This area (the lores) is white on most birds, and if it is, the bird is definitely a horned.
Horned grebes in summer plumage sport reddish necks and yellow “horns”on black heads. They are birds of the North, nesting on northern lakes and marshes and wintering on coastal bays or large lakes.
The call is trilling, with rising and falling notes, and has been described as squeaky and nasal. The common call in summer is a whining, nasal way-urrr or ja-orrr, descending and repeated. In winter, sometimes high, thin notes are heard.