The Common Loon I reported several weeks ago is still hunting the waters surrounding the Osprey nest at (the former) Alameda Naval Air Station. It has progressed to breeding plumage.
I regularly monitor the Osprey nest and must say the loon is a very occasional sighting, perhaps only on 20% of my visits.
The Osprey nest (and loon) location is at the very southern end of Monarch Avenue. You have to drive across two large concrete areas through two open gates to get to the end of Monarch (it doesn't look like a street) and dead end at the water's edge.
The Ospreys should be hatching eggs very soon.
Here's a photo of the loon: