Another uncommon w. rock lover, often on canyon walls. Its beautiful, clear descending notes often heard in its territory (Willow Warbler-like for Europeans). It creeps along rocks like BAWW, chiseling out food. Often elusive, it suddenly appears. A richly colored bird with white throat, duller cap, and very long downcurved bill. Juv plumage held briefly, duller with uniform breast.