Black dots moving as a group over SF Bay.

While exercising my dog with a friend, I looked out over the bay near Alcatraz Island. I saw what I initially thought were balloons released.
There was a scattering of about 15 black spots, possibly spheres. Most were in a scattered pattern and there was a clump of several.
The objects were moving all together, from West to East over the bay. My friend and I started hypothesizing what we thought they were.
We had several minutes to observe them as they moved across the sky. We dismissed the idea of balloons because we thought there looked too large from our vantage point. They moved all together and it seemed unlikely that the objects were propelled from the wind as they kept a random but distinct shape the whole time. It was not particularly windy that day but it could have been stronger at altitude.
I watch the sky often as I enjoy identifying birds. San Francisco has had many more birds of prey in the area since the COVID lock downs.
I am in the habit of looking up often. I'm also interested in aviation and like to note the various helicopters and aircraft in the region.
This sighting looked nothing like any air craft I've seen before. No sound was made either. It's possible these black objects where man made, we couldn't rule it out. We just thought it odd that these objects looked distinctly round even at a distance of about 1.5 miles out.
I estimate the distance at 1.5 miles b/c Alcatraz Island is also about that distance and these objects were not far past that distance.