Of course, this activity can be discussed in this sub-forum but, as you have noticed, there is very little in the way of wildlife photography here. I would suggest any of the very many photography forums available online if you would like to find discussions about gear for bird photography. Birdforum was mentioned, above, but I've found that Birdforum seems to be a better resource for discussing birds not necessarily the gear for capturing bird photos. Just about all the photography forums I have visited over the years have a good share of wildlife and bird photographers and many of these forums are more about the gear than the subjects. Another option is to go to Flickr and search for photos shot with your camera... ie, 'Canon Rebel birds' or 'Sony a6000 birds' or whatever camera you want to research... then, when you see a photo of interest, check to see what lens was used.
Generally speaking, impressive bird photography is highly dependent on distance to subject, focal length of lens, the quality of light, the direction of light, a steady hand or tripod, and the photographer's ability to focus quickly. Most wildlife shooters use lenses in the 400-600mm range. The closer you can get to the birds, the better, regardless of lens focal length. Always be aware of the light, light direction, the background and keeping the shutter speed as fast as possible.
You mentioned the San Francisco Bay area. I visited San Francisco a couple of years ago and that truly is a photographer's playground. I could have spent weeks just shooting all types of photography. Unfortunately, I had only an hour or two of actual photography at each of our destinations. I captured quite a few bird photos at the Palace of Fine Arts and I could easily have spent a lot more time there.
I'll add a strip of some of my bird photography. The gear I used has changed over the years. The cameras went from Olympus to Panasonic to Sony. The lenses were in the 400-600mm equivalent range. For the most part, today, I use my Sony a6000 camera body with a Canon L 400mm f5.6 lens, although, I used my Sony FE 200mm f4 lens in San Francisco because that Canon lens is large and I packed relatively lightly for that cross-country trip.