They ignored a pot full of yellow S. flava buds but, once again, are attacking S. leucophylla and S. purpurea buds. They either peck at or snap the buds right off. But always leave them lying right there.
I've thought of bagging the buds, but the birds always strike when the buds begin to open. I assume the yellow buds, like yellow strawberries and yellow raspberries, just aren't attractive to birds.