while co-leading the Golden Gate Audubon bird walk this morning, I found an adult male ROSE-BREASTED GROSBEAK on the north side of the Arboretum, about 50 yards east of the succulent garden feeding on thistle in a weedy patch between two paths. It was almost exactly in the same spot where I found a hatch year Rose-breasted Grosbeak on last year's December walk so it's possible this is a returning bird.
Best of all was that all three groups this morning were in the same area and everyone (I hope) got to see the bird.