The Harbor Seals whelped their pups on the beaches in late April, including several on the Big Creek cove beach. On May 15 I counted 152 seals between Dolan Rock and the seal beach. The Black Oystercatchers have apparently settled down to brood their eggs this spring. One adult has been settled on the nest for the last three weeks. The bird biologists at UCSC are very interested, since nests of these birds are normally very hard to observe.Several deer fawns have been sighted this May, all very young. It will be interesting to see if the trend away from twinning continues. In the fall of 1988 nearly all does were observed with twins, with the frequency declining each year. So far I have sighted three does with young this year, none of which included twins.
Last fall Jeff Norman alerted me to some caterpillars he saw feeding on French Broom (also called Genista or Cytissus monspessulanus), one of the most invasive weeds in our area. I visited Gail and David at Morning Glory Ranch near Lucia, and collected several caterpillars. After raising them for about 6 weeks in plastic bags containing French Broom leaves, they pupated in little woven cocoons. The moths emerged last month. They had brown forewings, orange hindwings, and had brush-like palps extending on the front of the head. I called Professor Jerry Powell at UC Berkeley and described them. He informed me that they are called Uresiphita reversalis, and that in California they feed primarily on French Broom, although in some areas they attack garden ornamental brooms. He was excited to learn that they are in Big Sur since this was the first record in our area. Apparently the moths invaded the San Francisco Bay area in the last 10 years from Southern California.
Jerry sent me some literature on this moth. Apparently the caterpillars are “aposematic,” that is brightly colored and highly visible to birds, and they store “quinolizidine” alkaloids in their gut and cuticle tissues. The toxic alkaloids probably protect the larger larvae from most predators. Jerry thinks the caterpillars are not capable of killing most broom plants. However, it is an encouraging sign that effective herbivores are beginning to attack this non-native plant, and it is possible that the combination of several species might actually control it. In most cases the success of non-native plants derives from the fact that they leave most of their herbivorous “enemies” behind when they immigrate to a new area. If anyone would like copies of the literature on this moth please call me at 667-2543 and I will mail you a copy.
The open house was not well attended this year, perhaps because of the lateness of the date and the competition with the Captain Cooper carnival. Next year we’ll schedule earlier in the spring. (5/29/91)