A Wood Duck, of course. On a trip with the Sea & Sage Audubon Society this morning at Santiago Oaks Regional Park, we found this pair apparently scouting out possible nesting sites:

They were being mobbed by Acorn Woodpeckers, but didn’t seem to mind too much. About half a dozen European Starlings were also present and scouting some of the same holes. I hope they lose the competition for the space.
In about 4 hours we logged some 30-odd species including:
- Wood Duck
- Great Egret
- Turkey Vulture
- Osprey
- Cooper’s Hawk
- Red-shouldered Hawk
- Red-tailed Hawk
- Mourning Dove
- Anna’s Hummingbird
- Belted Kingfisher
- Acorn Woodpecker
- Yellow-bellied Sapsucker
- Red-naped Sapsucker
- Nuttall’s Woodpecker
- Northern Flicker
- Cassin’s Kingbird
- Western Scrub-Jay
- American Crow
- Common Raven
- Tree Swallow
- Bushtit
- European Starling
- Orange-crowned Warbler
- Yellow-rumped Warbler
- Common Yellowthroat
- Spotted Towhee
- California Towhee
- Song Sparrow
- Dark-eyed Junco
- House Finch
- Lesser Goldfinch
- Nutmeg Mannikin
Yellow-bellied Sapsucker is a very good bird for the West Coast, though I’ve had numerous in New York already this year.
I’ll have to check and see whether the Nutmeg Mannikin is officially countable or not.
Read: What Kind of Duck Climbs a Tree?