The breeding adult Pied-billed Grebe Podilymbus podiceps is distinguished by its white eyeglasses and the black band on the beak. This one was photographed in July at the San Joaquin Preserve in Irvine, CA.
Photos 8144 and 8145 were taken in November at the same preserve. In the winter the white eyeglasses are still present but the black ring around the end to the bill is gone.