I've always been curious to find out when the statues disappeared from Sutro Heights. Based on photos, all the statuary was still in place in the late 1930s when the City took over the park following the death of Sutro's daughter Emma. (She was allowed to live in the mansion there as long as she wanted.) In fact, one 1939 newspaper story states the WPA was carrying out restoration on some of the statues.
To get an idea of how many statues once were scattered around the Heights, and how large some of them were, check out the photos in Christine Miller's "Album of Sutro Heights" at http://www.outsidelands.org/sh-intro.php
My memories kick in around 1955 when my parents took me to the Heights as a very little kid. I remember the lions at the main gate, Diana the Huntress, the Reclining Stag, and one creepy-looking statue of a guy who was half goat. (Based on historic photos I now know he was "Satyr's Dream.")
So what happened to the several dozen other pieces of statuary? Even the massive concrete pedestals many sat on have vanished. (Satyr's Dream and its pedestal were both gone by the time the NPS took control of the Heights in 1975.) Some were obviously damaged over the years, since gardeners keep finding little broken hands and noses and other concrete extremities while working around the old planter beds.