Sage Thrashers are indeed locally distributed in the Columbia Basin.Height
of sage in my opinion, is not so much a factor, for this species is common
in the very dwarfish (less than 24" high) 3-tip sage communities on north
and east slopes on the Yakima Training Center. What is important is
vegetation structure. Native grasses (Poa, Agropyron) supply this critical
structure. Shrub density is needed, but not height. In lowest and driest
parts of the basin, native grasses are rare-introduced cheatgrass seems to
have gained a permanent place there, at the expense of native grasses. In
higher and wetter parts of the basin, native grasses have persisted in more
locales, even with grazing. This is particularly true on north slopes. Sage
Thrashers have maintained good populations in these areas.

This notion of vegetation complexity in the shrub-steppe zone is analgous to
the complex structure found in old-growth forests. Reduce or eliminate this
highly varied structure and a reduction in bird and other animal species
dependent on that complexity decline or disappear.

Andy Stepniewski
Wapato WA