Kenn Kaufman in Lives of the Birds of NA gives some info

Diet: Mostly insects and spiders. Feeds on a variety of insects, including
termites, ants, beetles, leafhoppers, and others, also spiders. Forages by
hopping actively about in rock piles, up and down faces of steep rocky
cliffs, or through very dense undergrowth in canyons. Does much of its
foraging in sheltered spots. Uses its very long bill to probe deep into
crevices.
Nesting: Male defends territory by singing. Nest site is usually in hole or
crevice in rocky cliff. Nest (built by both sexes) has foundation of twigs,
grass, bark chips, and other coarse items, topped with cup of softer
materials such as fine grass, moss, leaves, spider webs, plant down, animal
hair, feathers. May add odd debris to nest.
Eggs: 5, sometimes 4-6, rarely 3-7. Incubation by female, 12-18 days. Male
may feed female during incubation.
Young: Both parents feed nestlings. Young leave the nest at about 15 days,
may remain with the parents for several weeks or more.

Hope this helps
Gail Spitler
Johnsons Landing, BC
spitler at wkpowerlink.com