Fairly common but often inconspicuous small diving bird of wetlands with bordering reeds and other vegetation. Often remains out of sight; less often out on open water (mainly in winter). Rather compact, with rounded head, puffy rear end. Seen mainly as singles and small loose flocks, often sleeping during the day. Breeding plumage often looks dark overall; in good light note dark rusty head and neck sides with yellow patch at base of bill. Nonbreeding plumage dingy pale brownish overall with dark cap.