These two grebe chicks were pestering two adult Western Grebes and begging for food. Both Western and Clark's grebes now breed at Lake Merced, but in the past I have only seen chicks of the Clark's Grebe. The back bird has a paler crown than the front, but I believe the gray crown extending all the way to the bill identifies both as Western Grebe and not Clark's.
Nesting is a relatively recent phenomenon at this site. Neither species is included in the San Francisco Breeding Bird Atlas and it's encouraging to see their success.
Digiscoped with Panasonic DMC-LZ5 | Nikon FieldScope 3 | 30X WA | hand-held (no adapter)