A pair of Mourning Doves (Zenaida macroura) and a pair of Curve-billed Thrashers (Toxostoma curvirostre) built their nests in the same 1.8 m Jumping Cholla (Opuntia fulgida) in a dry wash near River Rd., Tucson, Arizona, in May 1983. Unfortunately we have no observations of their behavioral interactions, but the doves were apparently there first and had two eggs in an advanced stage of incubation when the thrashers moved in, building up an old thrasher nest and depositing three eggs about 15 May just 0.5 m below the doves. Thus on 27 May when we found them, the doves' brood was about 8 days old and the thrashers were sitting on eggs. When we returned on 8 June both pairs were still in residence; the doves had fledged their brood and were now sitting on two new eggs while the thrashers downstairs were busily tending the young that had hatched during our absence.