Dunlin (all of them)
The last three may not be rarities, but eBird requested further documentation. Especially the Dunlin, where I estimated 2000-3000 birds in Cell 3 alone.
Though I would look I did not see either the (4) White-faced Ibis or the Tricolored Heron. Others saw them earlier in the morning, so they are still around. A pair of Osprey are nesting in the Humphries Unit.
An impressive flock of Dunlin and Ruddy Turnstones were working the north shoreline of the Humphries Unit near the eastern corner where the phragmites were burned away last spring. Flocks of Red-winged Blackbirds and Common Grackles were scattering in all directions along this stretch of the Middle Causeway, but I could not find a Yellow-headed Blackbird among them.
From the south side of Cell 3 a scope scan of the SW corner produced hundreds of Bonaparte's Gulls, and the two Little Gulls first reported on the 15th. A pair of Red-necked Phalarope could be seen swimming among the hundreds of Dunlin foraging in the area. A Black Tern was also a nice find near the tip of the muddy peninsula.
As I rode back to the car, a Yellow-headed Blackbird flushed from the grass next to the Middle Causeway in hot pursuit by a Red-winged Blackbird; both birds squabbling for (apparent) territory.
I could only watch them disappear back to the east.
Though I missed out on the White-faced Ibis, Tricolored Heron and Whimbrel, all three species would be reported/photographed today by other birders. If you can, now is the time to hit Pt. Moo!