Incubation exchange. Undoubtedly the pair is now waiting for a second brood to hatch after the first was lost. This is also what happened three years ago. We can safely conclude that there are eggs in the nest. The reason it has sometimes appeared to be abandoned is because the incubating adult is very deep and more to the rear of the nest. The front rim is also very high and the intervening Australian Pine "needles" (actually they are branches with tiny scale-like leaves which make them look like needles).
I arrived at the nest at 9:30 AM and watched until 10:45. Luis was there and Phil had been watching earlier and I just missed seeing him. Richard joined us. The male (Pride) was roosting on the center nest support branch and Jewel was nearly out of sight in the nest most of the time.
At around 9:50 Jewel appeared to tend the eggs, became restless and then flew up to join Pride on the branch.
They called together for a short period, and then Jewel flew to the east behind the trees.
Pride replaced her on the nest and remained out of sight except for occasional glimpses of the top of his head from that point on.
Jewel had roosted on a tree, set back from Pines Boulevard and about half way between the nest and SW 208th Avenue.
Light was from behind and it was difficult to get a clear image of her, but she remained at that spot and was still there when I departed.