Apparently something very similar to Fitz-bew.
We returned to La Gamba Road looking for a few more targets, one of them being the spinetail which we'd tried for the evening before. Long story short we didn't find the spinetail, but the call was close enough to Willow Flycatcher's that the flycatcher popped up and started singing; the book lists them as very uncommon in winter and they don't usually sing away from the breeding grounds.
We had more luck with slate-colored seedeater but the pic was terrible so here's the trip's first official Yellow-bellied Seedeaters (a Crossley'd montage of an adult and subadult male) that were in the same place.
A Pale-vented Pigeon across the street was the only one I photographed the entire trip.
We walked out into a grassy (rice?) field to play tapes from some rail or crake that remained silent. Vernon pointed out Blue Ground-doves calling. A few of the group had seen them as flyby's at various points. He described where on the trees they typically perched. I found this bird just where his search image described.