This is a neighbour’s tree, which overhangs our yard. Many of the branches are at least partially denuded, especially near the top, thanks to the foraging of a mob of House Finches. They are plucking the blossoms, as described in this account of the closely related Purple Finch:
“In February of 1939, at my home in Berkeley, California, I noticed that the California Purple Finches (Carpodacus purpureus californicus) were singing every morning in a plum tree which was in full bloom. On closer observation the birds were seen to be plucking blossoms. Each bird worked systematically, and in one movement picked a blossom and snipped open the base; it then removed the nectar while holding the blossom in the bill, following which it dropped the blossom to the ground. Upon examination the dropped blossoms were found to be undamaged except for removal of the nectar. The birds’ unhurried swiftness was interrupted only when they paused to sing.” Ned W. Stone (1939) The Nectar Eating Habits of the Purple Finch. Condor 42: 126.
The House Finch is closely related (Carpodacus mexicanus), so it isn’t surprising that it does the same thing. And with gusto. They seem to be doing a lot with gusto, including chasing each other and other birds from the sunflower-seed feeder and the seed-littered ground beneath it. Females are fluttering their wings at males, and males are feeding them seeds. I haven’t seen a male offer a blossom though. Perhaps it’s not possible, the nectar will run out in transfer, or perhaps males need all that nectar themselves to keep up with the frantic pace of spring-things. In any case, the females are filching flowers too.
...and then the last...