I first noticed this nest on May 10, 2011, when a male Northern Flicker was looking out of the cavity. The male was looking out again on May 17, and then it backed down into the cavity. On June 11 and 12, I saw the parents feed nestlings at the nest multiple times. On June 11, I was able to see 3 nestlings. They were fully feathered but the egg tooth was still visible. The nest was in an alder(?) snag, along West Slough.
I have posted a few videos on YouTube that show the male and female feeding the nestlings (http://youtu.be/PFISMbqf3Yw, http://youtu.be/VdT5ywXNEG0). In the video with the male, you can see that he seems to be feeding the nestlings by regurgitation. The Northern Flicker species account in the Birds of North America says: "Pharynx of adult expands to form a crop, which is engorged, particularly with ant larvae, when adult returns to nest. Young fed by regurgitation." The video with the male also shows him removing a fecal sac.
The pictures that I've posted here show the male approaching the nest cavity (June 12), the male removing a fecal sac (June 12), one of the parents feeding a nestling (June 11), a nestling looking out of the nest (June 11), and the nest-site.