This small grebe is mainly a prairie breeder wintering on both coasts but sometimes does breed in Ontario, especially in the west, and is fairly common in migration. A few have wintered in southern Ontario. (Birds of Ontario)
I see seen several wintering this year at Col. Sam Smith Park and here at Humber Bay. The clean cut black cap identifies it as a Horned Grebe in winter plumage.
Here is one in breeding plumage.
Shine out, fair Sun, with all your heat, Show all your thousand-coloured light! Black Winter freezes to his seat; The grey wolf howls, he does so bite; Crookt Age on three knees creeps the street; The boneless fish close quaking lies And eats for cold his aching feet; The stars in icicles arise: - George Chapman 1600