I’ve often noticed that before the saguaros start to flower, their crowns whiten. This photo shows why: the flowers bud out of white discs on the ridges of the pleats.
On the way back down the west side of the wash, there was a yellow paloverde full of birds: Verdins, Black-tailed Gnatcatchers, and what I think was an Orange-crowned Warbler. The song was an accelerating trill on a rising note. I spotted a yellow bird with a black eye-stripe, but never saw it singing. I checked out the songs of warblers when I got back, and the Orange-crowned Warbler was a close match. The sighting might have been one of the Verdins hopping around in the same tree.
There was a pair of Abert’s Towhees calling to each other nearby.