As for flora around the area there really wasn't that much. This is sacred datura, aka western jimson weed. It closes up in the daytime/sunlight and actually blooms at night. Click on the link to read more about this plant.
Overall, we really enjoyed this birding festival. There is such a variety of geographic possibilities which gives one a wide variety of bird species to be found. I recommend this birding festival to anyone who plans on visiting central coast California in late September. And almost guaranteed great sunshiny weather.